Original Article
Development and validation of an alternative procedure for quantitative quality control analysis of 99mTc-radiopharmaceuticals using a Geiger Müller counter
Desarrollo y validación de un procedimiento alternativo para realizar los controles de pureza radioquímica de radiofármacos de 99mTc con un contador Geiger Müller
a Departamento de Producción de Radioisótopos, Centro Integral de Medicina Nuclear y Radiofarmacia de Bariloche, Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Río Negro, Argentina
b Instituto de Nanociencia y Nanotecnología, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Río Negro, Argentina
c Servicio de Medicina Nuclear, Centro Integral de Medicina Nuclear y Radiofarmacia de Bariloche, Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Río Negro, Argentina
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(A,B) [<span class="elsevierStyleSup">18</span>F]FDG PET/CT. (C,D) [<span class="elsevierStyleSup">68</span>Ga]Ga-DOTA-TOC PET/CT. (A,C) Hepatic lesion with hypermetabolism in the FDG study (red cross) without pathological expression of SSTR (white cross). (B,D) Hepatic lesion with uptake of both radiopharmaceuticals (blues crosses).</p>" ] ] ] "autores" => array:1 [ 0 => array:2 [ "autoresLista" => "Z. Nogareda Seoane, M.C. Mallón Araújo, A. Calatayud Cubes, C. Barberán Corral, Y. Domínguez Novoa, A. Cousillas Castiñeira, N. Martínez Lago, J.M. de Matías Leralta, V. Pubul Nuñez" "autores" => array:9 [ 0 => array:2 [ "nombre" => "Z." "apellidos" => "Nogareda Seoane" ] 1 => array:2 [ "nombre" => "M.C." "apellidos" => "Mallón Araújo" ] 2 => array:2 [ "nombre" => "A." "apellidos" => "Calatayud Cubes" ] 3 => array:2 [ "nombre" => "C." "apellidos" => "Barberán Corral" ] 4 => array:2 [ "nombre" => "Y." "apellidos" => "Domínguez Novoa" ] 5 => array:2 [ "nombre" => "A." 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Gonzalez, A.L. Poma, N. Cuello, A.L. Soldati" "autores" => array:4 [ 0 => array:3 [ "nombre" => "M.M." "apellidos" => "Gonzalez" "referencia" => array:2 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">a</span>" "identificador" => "aff0005" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] ] ] 1 => array:3 [ "nombre" => "A.L." "apellidos" => "Poma" "referencia" => array:2 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">c</span>" "identificador" => "aff0015" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">1</span>" "identificador" => "fn0001" ] ] ] 2 => array:3 [ "nombre" => "N." "apellidos" => "Cuello" "referencia" => array:2 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">a</span>" "identificador" => "aff0005" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">2</span>" "identificador" => "fn0005" ] ] ] 3 => array:4 [ "nombre" => "A.L." "apellidos" => "Soldati" "email" => array:1 [ 0 => "analia.soldati@intecnus.org.ar" ] "referencia" => array:3 [ 0 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">a</span>" "identificador" => "aff0005" ] 1 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">b</span>" "identificador" => "aff0010" ] 2 => array:2 [ "etiqueta" => "<span class="elsevierStyleSup">*</span>" "identificador" => "cor0005" ] ] ] ] "afiliaciones" => array:3 [ 0 => array:3 [ "entidad" => "Departamento de Producción de Radioisótopos, Centro Integral de Medicina Nuclear y Radiofarmacia de Bariloche, Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Río Negro, Argentina" "etiqueta" => "a" "identificador" => "aff0005" ] 1 => array:3 [ "entidad" => "Instituto de Nanociencia y Nanotecnología, Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Río Negro, Argentina" "etiqueta" => "b" "identificador" => "aff0010" ] 2 => array:3 [ "entidad" => "Servicio de Medicina Nuclear, Centro Integral de Medicina Nuclear y Radiofarmacia de Bariloche, Comisión Nacional de Energía Atómica (CNEA), San Carlos de Bariloche, Río Negro, Argentina" "etiqueta" => "c" "identificador" => "aff0015" ] ] "correspondencia" => array:1 [ 0 => array:3 [ "identificador" => "cor0005" "etiqueta" => "⁎" "correspondencia" => "Corresponding author." ] ] ] ] "titulosAlternativos" => array:1 [ "es" => array:1 [ "titulo" => "Desarrollo y validación de un procedimiento alternativo para realizar los controles de pureza radioquímica de radiofármacos de <span class="elsevierStyleSup">99m</span>Tc con un contador Geiger Müller" ] ] "resumenGrafico" => array:2 [ "original" => 0 "multimedia" => array:8 [ "identificador" => "fig0020" "etiqueta" => "Fig. 4" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr4.jpeg" "Alto" => 1651 "Ancho" => 1675 "Tamanyo" => 100468 ] ] "detalles" => array:1 [ 0 => array:3 [ "identificador" => "at0020" "detalle" => "Fig. " "rol" => "short" ] ] "descripcion" => array:1 [ "en" => "<p id="spar0020" class="elsevierStyleSimplePara elsevierViewall">Effect of the hardening of the spectrum caused by the increase in volume of the source and self-attenuation.</p>" ] ] ] "textoCompleto" => "<span class="elsevierStyleSections"><span id="sec0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0075">Introduction</span><p id="par0005" class="elsevierStylePara elsevierViewall">Quality control of the family of radiopharmaceuticals labelled with [<span class="elsevierStyleSup">99m</span>Tc]Tc using freeze dried cold kits (such as methylene diphosphonate [MDP] or myocardial perfusion imaging [methoxyisobutylisonitrile — MIBI]) for the quantification of radiochemical purity requires the use of an analytical method for the determination of the presence of impurities such as ascending paper or vial partitioning chromatography.<a class="elsevierStyleCrossRef" href="#bib0005"><span class="elsevierStyleSup">1</span></a> The fractions obtained represent the quantity of labelled pharmaceutical versus free or colloid pharmaceutical and they should be measured in an activimeter, such as that used for fractioning the monodoses of a radiopharmaceutical, or directly in a dedicated detector. This process is performed in conventional nuclear medicine radiopharmacies and is necessary and a prerequisite for the administration of the radiopharmaceutical to the patients since the physicochemical and nuclear characteristics of the labelled product can compromise the quality of the study.<a class="elsevierStyleCrossRef" href="#bib0010"><span class="elsevierStyleSup">2</span></a></p><p id="par0010" class="elsevierStylePara elsevierViewall">Ascending paper chromatography is traditionally used for the determination of the radiochemical purity of technetium radiopharmaceuticals. With the use of a mobile and a stationary phase, this test allows the separation of impurities that arise from the preparation of the radiotracer, which usually comprises [<span class="elsevierStyleSup">99m</span>Tc]-pertechnetate and [<span class="elsevierStyleSup">99m</span>Tc]-colloid, from the portion of the activity of the correctly labelled radiopharmaceutical.<a class="elsevierStyleCrossRef" href="#bib0015"><span class="elsevierStyleSup">3</span></a> Alternatively, vial partitioning chromatography may be applied. This method has two phases, one with affinity for the radiopharmaceutical, while the other, the fraction of activity corresponding to the impurities, is located in the other phase.<a class="elsevierStyleCrossRef" href="#bib0015"><span class="elsevierStyleSup">3</span></a> In contrast to ascending paper chromatography in which the radiochemical purity is determined by comparing the activity of the impurities and the radiopharmaceutical measured separately (with the use of an activimeter), in the case of partition chromatography, an integrated detector is necessary, which measures the activity of each phase separately and simultaneously during a certain period of time. This is generally achieved with the use of an intermediate lead plate or by collimating the incident beam on the detector corresponding to each phase, notably reducing the detection of photons from the other phase. An example of this system is found in commercial equipment for the labelling and quality testing of radiopharmaceuticals (BAC MT from Laboratorios Bacon SAIC was the one used here) in which the percentage of counts detected in the phase containing the correctly labelled radiopharmaceutical is determined with respect to the undesired residues from the labelling process, in a liquid chromatography partition vial in which an aliquot of radiotracer activity is injected. This system has two independent solid state detectors which count the events of each of the liquid phases from the collimation of the beam through separate holes made in the upper and lower regions of a lead plate in which the partition vial is inserted.</p><p id="par0015" class="elsevierStylePara elsevierViewall">Dose calibrators, also known as activimeters, used in nuclear medicine radiopharmacies are usually gas detectors that work in the range of an ionization chamber (IC).<a class="elsevierStyleCrossRef" href="#bib0020"><span class="elsevierStyleSup">4</span></a> In this type of detectors, gas molecules lodge in a pressurized tube are subjected to a difference in potential between two electrodes (usually in the range of 50–300 V). The indirect ionizing radiation (such as the gamma photons of [<span class="elsevierStyleSup">99m</span>Tc]Tc) is transformed by a photocathode into electrons, which, on entering the gas tube, become excited and ionize the gas molecules forming ionic pairs (ion-electron), which are collected by the application of a voltage potential difference. The amplitude of the signal produced is directly proportional to the energy deposited by the primary electron and is independent of the voltage applied between the electrodes.<a class="elsevierStyleCrossRef" href="#bib0025"><span class="elsevierStyleSup">5</span></a></p><p id="par0020" class="elsevierStylePara elsevierViewall">On the other hand, Geiger Müller (GM) detectors, known since 1928, are frequently used in the setting of radiological protection and monitoring due to their robustness, simplicity and low detection limit.<a class="elsevierStyleCrossRef" href="#bib0030"><span class="elsevierStyleSup">6</span></a> The physical principle of functioning is based on the ionization of molecules inside a tube full of gas, but in this case the gas is subjected to a high electric field (500–2000 V) producing the multiplication of the initial charge by a cascade of successive ionizations until the discharge level is reached. Since this level is independent of the energy originally deposited, all the pulses obtained in a GM will have the same amplitude, allowing a greater signal to be obtained than that of the proportional counters or IC. The cost is loss of information on the quantity of energy deposited by the first free electron originally produced in the photocathode by the incident radiation.<a class="elsevierStyleCrossRef" href="#bib0035"><span class="elsevierStyleSup">7</span></a> Another characteristic of this type of detectors is the long characteristic times (of around 50–100 μs), which allows better functioning to determine low count rates.<a class="elsevierStyleCrossRef" href="#bib0040"><span class="elsevierStyleSup">8</span></a> However, these requisites are compatible with the requirements of the of 2a level hospital radiopharmacies, which use small aliquots of radiopharmaceuticals labeled in quantities of less than 37 MBq (1 mCi), generally within the order of 0.37–18.5 MBq (0.01−0.5 mCi).</p><p id="par0025" class="elsevierStylePara elsevierViewall">The possibility of having access to an alternative detector for quality control analyses may be useful in situations in which the equipment normally used is momentarily occupied in the same department or when the background activity is of the same order as the radiopharmaceutical aliquot́s activity which radiochemical purity is to be controlled. The advantage of this methodology is that the GM detector can be easily transferred to another sector, reducing the background signal.</p><p id="par0030" class="elsevierStylePara elsevierViewall">Here we present a feasibility study on the use of a GM counter with probe for measuring surface contamination for the measurement of the radiochemical purity of technetium radiopharmaceuticals. The same is routinely used in the Nuclear Medicine Department as a radiation monitor and for detecting, for example, the presence of contamination using the wipe test with Whatman type filter paper. The studies of systematic errors, response to concentration of activity and measurement time, and the activity of saturation were compared with the obtained by the activimeter, using an elution of [<span class="elsevierStyleSup">99m</span>Tc]pertechnetate. Lastly, a method to perform the radiochemical purity test with this detector was developed and then evaluated for the quality control of the [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP and [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI compounds using the separation by paper chromatography compared with the vial partition method measured in dedicated equipment.</p></span><span id="sec0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0080">Material and methods</span><p id="par0035" class="elsevierStylePara elsevierViewall">To evaluate the proposed methodology of control of radiochemical purity with the chromatography/GM system two detectors routinely used in the Nuclear Medicine Department were used: a Geiger Müller Thermo Scientific FH40G detector (Thermo Fisher Scientific, United States) used for radioprotection purposes and a Veenstra Comecer VDC 505 ionization chamber (Comecer, Netherlands) calibrated in a secondary laboratory under permanent quality controls and used for fractioning and quantifying radiopharmaceutical doses.</p><p id="par0040" class="elsevierStylePara elsevierViewall">The GM model used has a probe for measuring surface contamination and a closed lead sample holder in which the paper samples are placed under the probe. The microtubes (Eppendorf) containing the radiopharmaceutical solution are placed horizontally at the bottom of this chamber, while the papers are measured in the center of the it with the inoculated side upwards. In the case of the IC, the paper samples are measured at the bottom of the dose calibrator dipper and the microtubes in the same geometry used to quantify the dose in syringes. The samples placed in the dipper of the activimeter were positioned so that the solid angle of detection was maximized, prioritizing, in both cases, the need to place the sample in the same position in each measurement and carrying out a study of the incidence of the volume in the activity measured as described later.</p><p id="par0045" class="elsevierStylePara elsevierViewall">After the measurement of the activity (in the IC) and the counts per second (in the GM) of different sources of <span class="elsevierStyleSup">99m</span>Tc, an analysis of systematic errors and response to the concentration of activity and measurement time as well as the saturation activity was performed. In the settings shown in <a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>, samples of [<span class="elsevierStyleSup">99m</span>Tc]pertechnetate between 5 and 500 μl in volume and 0.028 MBq (0.75 μCi) to 18.5 MBq (500 μCi) were measured for times of 30–90 s (interval 30 s, IC) and 10–120 s (intervals of 10 s, GM).</p><elsevierMultimedia ident="fig0005"></elsevierMultimedia><p id="par0050" class="elsevierStylePara elsevierViewall">The samples were obtained from a freshly eluted solution of 740 MBq/ml (20 mCi/ml) of [<span class="elsevierStyleSup">99m</span>Tc]pertechnetate, which was successively diluted in saline solution for achieving the concentrations indicated in <a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>. The samples in the liquid matrix were prepared directly in 2 ml microtubes. The samples in the dry matrix were obtained seeding a microdrop of 5 μl of solution on Whatman N̊ 1 filter paper.</p><elsevierMultimedia ident="tbl0005"></elsevierMultimedia><p id="par0055" class="elsevierStylePara elsevierViewall">After this study, a calibration curve was determined for the range of activities of the samples used, which, in addition to serving for the development of this procedure, can be useful for the determination of the activity of contamination in wipe tests aimed at radioprotection. Lastly, the performance of the methodology proposed was tested to determine the radiochemical purity of the [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP and [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI compounds compared with that obtained with the activimeter and with the vial partitioning method measured in the BAC MT (Laboratorios BACON, SAIC; Argentina).</p><span id="sec0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0085">Determination of errors in the measurement of radioactivity (IC) and counts per second (GM)</span><p id="par0060" class="elsevierStylePara elsevierViewall">Given a concentration of radioactivity (calculated from the activity measured divided by the volume of the sample) for the same geometry and sample matrix, the uncertainty is calculated as the systematic error of measurement plus the geometric error of the same. In turn, the systematic error, is composed of two errors: (i) the systematic error in the measurement of the volume of the sample, originated in the pipetting and dilution, and (ii) the systematic error of the detector in question on measuring the activity or the number of counts.</p><p id="par0065" class="elsevierStylePara elsevierViewall">To determine the systematic error in the measurement of sample volume, 10 samples of a volume equal to 100 μl and a nominal activity of 3.7 MBq (100 μCi) each, were prepared (marked with * in <a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>). The activity was measured in the IC and the number of counts accumulated during 60 s was measured in the GM. On the other hand, to determine the range of systematic errors of the detector, independently of the volume of the sample, 10 measurements of paper samples of 3.7 MBq (100 μCi) and 0.185 MBq (5 μCi) were averaged.</p><p id="par0070" class="elsevierStylePara elsevierViewall">The third contribution to uncertainty is that of the geometry of the sample. To determine this, we used 2 ml Eppendorf type tubes with the same [<span class="elsevierStyleSup">99m</span>Tc]pertechnetate activity diluted in different volumes of saline solution. The nominal activity of 3.7 MBq (100 μCi) was diluted into volumes of 25, 50, 100, 250 and 500 μl (see <a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>).</p><p id="par0075" class="elsevierStylePara elsevierViewall">In all the cases the values were corrected for the decay time from the beginning of the measurement and the background was subtracted.</p></span><span id="sec0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0090">Response of the detectors to activity, concentration of activity and measurement time</span><p id="par0080" class="elsevierStylePara elsevierViewall">Taking into account the characteristics of each detector, an error in the determination of radioactivity and the concentration of activity depends on several factors related to the physics of the detection and the characteristic times of this process.</p><p id="par0085" class="elsevierStylePara elsevierViewall">To characterize the response of the GM detector to activity, one to five microdrops (5 μl per microdrop, one on top of another) of a [<span class="elsevierStyleSup">99m</span>Tc]pertechnetate solution were placed on 1 cm<span class="elsevierStyleSup">2</span> pieces of Whatman N̊ 1 filter paper (See <a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>, samples of paper matrix). These papers were left to dry and then measured in the detector chamber with the inoculated side face up, taking data every 10 s during a time period of 300 s. The number of counts per second was corrected by the decay time.</p><p id="par0090" class="elsevierStylePara elsevierViewall">To evaluate the response to the concentration of activity, the liquid samples with activities of between 0.925 MBq (25 μCi) and 18.5 MBq (500 μCi) in final volumes of 25–500 μl were analyzed in a configuration similar to that used for measuring the fractionated activity in a syringe (See <a class="elsevierStyleCrossRef" href="#tbl0005">Table 1</a>, samples of liquid matrix). Additionally, the response obtained for the samples in paper matrix with activities of 0.009 MBq (0.25 μCi) to 3.7 MBq (100 μCi) seeded on Whatman N° 1 filter paper was analyzed in a configuration similar to that used to determine the radiochemical purity by ascending paper chromatography.<a class="elsevierStyleCrossRef" href="#bib0045"><span class="elsevierStyleSup">9</span></a> In both cases, measurement was made during periods of time of 30, 60 and 90 s for IC and every 10 s up to 120 s for GM.</p></span><span id="sec0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0095">Cross calibration</span><p id="par0095" class="elsevierStylePara elsevierViewall">From the measurement of the different samples the cross calibration curves between the two equipment were performed covering the range from 0 to 3.7 MBq (100 μCi) for the paper matrix and from 0 to 18.5 MBq (500 μCi) for the liquid matrix. The data were fitted with a line by the least squares method.</p></span><span id="sec0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0100">Procedure for the measurement of the radiochemical purity of [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP and [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI</span><p id="par0100" class="elsevierStylePara elsevierViewall">The methodologies of ascending paper and vial partition chromatography provided by Laboratorios BACON SAIC (Argentina) were used for the measurement of the radiochemical purity of the [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP and [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI radiopharmaceuticals. To ensure that the radiopharmaceutical passed the quality control, a radiochemical purity greater than 90% was required in both cases.</p><p id="par0105" class="elsevierStylePara elsevierViewall">Ascending paper chromatography is a physicochemical separation method that uses a stationary phase (a paper) and a liquid phase (a solution or solvent) that ascends on the paper by capillarity, dragging with it the compounds of the substance to be separated that are most chemically similar to it. The ascending paper chromatography method consists in seeding a microdrop of the labeled radiopharmaceutical in the center of the seeding line of the chromatographic paper (generally at 2 cm from the bottom). The lower part of the paper is then submerged in a closed cell with the corresponding solution, paying special attention to removing the paper when the solvent front exceeds the established maximum height of migration. Finally, it is left to dry for two minutes and the corresponding fractions are cut to measure the activity or counts in the radiation detector (<a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>). The substances that are similar to the mobile phase appear later with the solvent front (on the upper edge) while the less related substances do not move and remain on the seeding line.</p><span id="sec0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0105">Ascending paper chromatography [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP</span><p id="par0110" class="elsevierStylePara elsevierViewall">For the study with [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP, Whatman N°1 filter paper was used, cut into rectangles of 1.5 × 10 cm for the stationary phase and two solvents for the mobile phase: sodium chloride 0.9% (System A) and methanol water 85:15 (System B). The percentage of radiochemical purity of the [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP was calculated according to the equations shown in <a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>A.</p></span><span id="sec0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0110">Ascending paper chromatography [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI</span><p id="par0115" class="elsevierStylePara elsevierViewall">In the case of [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI, absolute ethanol on an instant thin layer chromatography sheet was the only system used as the mobile phase (System A) (<a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>B). The activity of each of the run fragments was measured by both the activimeter and the GM detector, integrating 30 s. The percentage of radiochemical purity was calculated as shown in the same figure.</p></span><span id="sec0045" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0115">Partitioning vials</span><p id="par0120" class="elsevierStylePara elsevierViewall">For the determination of radiochemical purity with the partitioning vials, the percentage of activity of the phase related to each radiotracer was measured with respect to the total activity of the system with the detector included in the oven of [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI and using the partition vials for the quality control of [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP and [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI (both supplied by Laboratorios BACON, SAIC, Argentina). The partitioning vials are 2 ml glass vials with a rubber top stapled in aluminum, filled with two immiscible solutions. One of the phases corresponds to a hydrophilic solution (generally saline solution) while the other phase depends on the radiotracer. In the case of [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP, the phase related to the radiopharmaceutical contains sodium acetate, while for [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI the related phase contains chloroform.</p><p id="par0125" class="elsevierStylePara elsevierViewall">The procedure consists in taking a drop from the vial of the radiopharmaceutical labelled with an activity of around 37 MBq (1 mCi) in a 1 ml syringe and introduce this into the corresponding partitioning vial. Shake the vial for 5 s and leave it to rest until the phases, which are immiscible, separate and are located, one on top of the other, without presenting drops on the surface. Then the vial is inserted into the test equipment (BAC-MT, BACON SAIC) and measured according to the manufacturer’s instructions. On completing the control process (60 s), the equipment emits a sound signal and provides the percentage of purity measured, that is, the activity of the phase related to the pharmaceutical with respect to the activity corresponding to both phases.</p></span></span></span><span id="sec0050" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0120">Results</span><span id="sec0055" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0125">Determination of errors</span><p id="par0130" class="elsevierStylePara elsevierViewall">The systematic error in the measurement process of a sample of nominal radioactivity of 3.7 MBq (100 μCi) in the IC produces an uncertainty of 0.5%, while the error introduced by GM is 1.3%. These values rise to 2.7% and 4.8%, respectively, when the nominal activity descends to 0.185 MBq (5 μCi). Meanwhile, the systematic error of the dilution obtained from the measurement of 10 samples of nominal activity of 3.7 MBq (100 μCi) in a volume of 100 μl, is equal to 1.6% in both cases, and takes into account the pippeting errors.</p><p id="par0135" class="elsevierStylePara elsevierViewall">Considering the geometric error, such as that which arises from measuring samples with the same nominal activity with different volumes, samples of nominal activity of 3.7 MBq (100 μCi) of volumes between 25 and 500 μl were measured with both detectors. The resulting average geometric error was 3.90% for IC and 1.57% for GM.</p><p id="par0140" class="elsevierStylePara elsevierViewall">Taking this into account, the total error can be calculated as the root of the sum of the squared errors of each case, resulting in an uncertainty of between 4% and 5% for IC and between 3% and 5% for GM for activities between 0.185 MBq (5 μCi) and 3.7 MBq (100 μCi). That is, the maximum uncertainty expected for a measurement of counts (GM) or a measurement of activities (IC) with these methods is ±5%.</p></span><span id="sec0060" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0130">Uncertainty and measurement time</span><p id="par0145" class="elsevierStylePara elsevierViewall">While the IC has a stabilization time of a few seconds, the GM detector requires an accumulation of counts for providing a more precise result. <a class="elsevierStyleCrossRef" href="#fig0010">Fig. 2</a> shows that for all the concentrations measured in the range studied the dispersion of the values with respect to the nominal value presents a minimum of around 60 s, and remains under 2% for longer times. Therefore, using measurement times of 60 s, the error introduced in the detection of counts is lower than that which would be expected taking systematic and geometric errors into account.</p><elsevierMultimedia ident="fig0010"></elsevierMultimedia></span><span id="sec0065" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0135">Uncertainty and source volume</span><p id="par0150" class="elsevierStylePara elsevierViewall">As shown in <a class="elsevierStyleCrossRef" href="#fig0015">Fig. 3</a>, for both the nominal activity of 3.7 MBq (100 μCi) and for that of 18.5 MBq (500 μCi), the activity detected in the IC increases with the increase in the volume of the source, while for GM the number of counts per second detected shows a contrary behavior.</p><elsevierMultimedia ident="fig0015"></elsevierMultimedia><p id="par0155" class="elsevierStylePara elsevierViewall">The difference observed is to be expected since, on one hand, IC has a cylindrical geometry in which the sample is inserted in a position close to the axial axis in the interior of the detector. For this reason, and due to the subtended solid angle of the sample, a volumetric sample is better detected than a spot sample, and thus, the greater the volume the greater the activity measured for the same nominal activity. On the other hand, GM has a flat detector placed over the source at a fixed distance, and thus, the difference of volume is not as determinant in the geometry of the measurement, provided that the source is small enough.</p><p id="par0160" class="elsevierStylePara elsevierViewall">Additionally, the effect of self-attenuation of the radiation produced by the medium in which the source is dissolved, modifies the spectrum of incident photons in the detector. On one hand, the photons totally absorbed in the sample no longer reach the detector, while on the other hand, the photons that interact losing energy but are able to leave the sample produce the displacement of the spectrum to lower energies. This is translated into an increase in the probability of occurrence of the Compton effect, which increases the background in the left side of the photopeak.</p><p id="par0165" class="elsevierStylePara elsevierViewall">In the IC this is translated as a reduction of activity read in a point source with respect to a volumetric source, since the photons with energy less than the calibration fall outside the window of measurement. To the contrary, the GM detector counts each photon that reaches it as a count, independently of its energy, observing an increase in the number of counts detected when the source tends to be punctual, being a case in which it can be considered that the total absorption is negligible (see <a class="elsevierStyleCrossRef" href="#fig0020">Fig. 4</a>).</p><elsevierMultimedia ident="fig0020"></elsevierMultimedia></span><span id="sec0070" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0140">Cross calibration</span><p id="par0170" class="elsevierStylePara elsevierViewall">The net counts per second measured in the GM detector corrected for decay time and background were plotted based on the activity measured with the IC for both the samples inoculated on paper (<a class="elsevierStyleCrossRef" href="#fig0025">Fig. 5</a>A) and for disperse samples in a liquid matrix (<a class="elsevierStyleCrossRef" href="#fig0025">Fig. 5</a>B). Linear fit by least squares provides a coefficient r<span class="elsevierStyleSup">2</span> > 0.99 in both cases.</p><elsevierMultimedia ident="fig0025"></elsevierMultimedia><p id="par0175" class="elsevierStylePara elsevierViewall">The curve in paper matrix can be used to convert the counts per second in the range of 0–2.7 MBq (0–75 Ci) into activities, allowing not only quality controls of the radiopharmaceuticals by ascending paper chromatography but also quantitative evaluation of surface contamination tests (swipe test).</p><p id="par0180" class="elsevierStylePara elsevierViewall">On the other hand, when the matrix is liquid, the response of the GM detector has greater dispersion due to the previously mentioned geometric and self-absorption considerations. In this case, the prediction band of 90% for the measurement of counts is ±0.8 MBq (22 μCi) in the range studied.</p></span><span id="sec0075" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0145">Control of radiochemical purity</span><p id="par0185" class="elsevierStylePara elsevierViewall">The results of the quality control of radiochemical purity with the methods of chromatographic separation and separation in partitioning vials are shown in <a class="elsevierStyleCrossRef" href="#tbl0010">Table 2</a>. Considering the results in Section “Determination of errors,” the error reported by the chromatographic method was calculated taking into account a maximum uncertainty of ±5% for the measurements of counts per second (GM) or activity (IC) of each fraction of chromatographic paper analyzed (See <a class="elsevierStyleCrossRef" href="#fig0005">Fig. 1</a>). Measurement uncertainty in the BAC-MT® equipment was considered as the last significant digit of the value shown on the screen.</p><elsevierMultimedia ident="tbl0010"></elsevierMultimedia><p id="par0190" class="elsevierStylePara elsevierViewall">The purity found for [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI by chromatography coincided with the results of the vial partitioning within its interval of error, while the purity of [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP differed by less than 3.3%. With the latter radiopharmaceutical, the difference lies more in the method of separation, since paper chromatography is able to separate and quantify the hydrolyzed and colloid Tc while the vial partitioning method cannot. On the other hand, the results obtained by the chromatographic strips with the GM detector or with the IC differed by less than 1%, clearly supporting the alternative use of a GM as an occasional replacement of an activimeter in the quality control of radiochemical purity of these radiopharmaceuticals.</p></span></span><span id="sec0080" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0150">Conclusions</span><p id="par0195" class="elsevierStylePara elsevierViewall">The present study evaluated a Geiger Müller detector as an alternative for performing quality controls of technetium radiopharmaceuticals labelled using freeze-dried kits. The analysis of systematic and geometric errors showed that the quality of the measurement is equivalent to that performed with an activimeter. The determination of radiochemical purity of the [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP and [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI compounds by ascending paper chromatography measured with the GM detector probe produced values comparable to those measured with an activimeter and with the vial partitioning method provided by Laboratorios BACON SAIC. The results of this study show that the GM detector may be used to replace other equipment for the control of radiochemical purity. Likewise, the possibility of using cross calibration with certified equipment (ionization chamber) demonstrated that it is possible to measure activities from 0.1 MBq to 2.6 MBq, which allows using the probe quantitatively for the measurement of contamination in the swipe test for purposes of radiological protection.</p></span><span id="sec0085" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0155">Conflict of interest</span><p id="par0200" class="elsevierStylePara elsevierViewall">The authors have no conflicts of interest to declare.</p></span></span>" "textoCompletoSecciones" => array:1 [ "secciones" => array:10 [ 0 => array:3 [ "identificador" => "xres2219012" "titulo" => "Abstract" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "abst0005" "titulo" => "Background and objectives" ] 1 => array:2 [ "identificador" => "abst0010" "titulo" => "Materials and methods" ] 2 => array:2 [ "identificador" => "abst0015" "titulo" => "Results" ] 3 => array:2 [ "identificador" => "abst0020" "titulo" => "Conclusions" ] ] ] 1 => array:2 [ "identificador" => "xpalclavsec1859357" "titulo" => "Keywords" ] 2 => array:3 [ "identificador" => "xres2219011" "titulo" => "Resumen" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "abst0025" "titulo" => "Antecedentes y objetivo" ] 1 => array:2 [ "identificador" => "abst0030" "titulo" => "Materiales y métodos" ] 2 => array:2 [ "identificador" => "abst0035" "titulo" => "Resultados" ] 3 => array:2 [ "identificador" => "abst0040" "titulo" => "Conclusiones" ] ] ] 3 => array:2 [ "identificador" => "xpalclavsec1859356" "titulo" => "Palabras clave" ] 4 => array:2 [ "identificador" => "sec0005" "titulo" => "Introduction" ] 5 => array:3 [ "identificador" => "sec0010" "titulo" => "Material and methods" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "sec0015" "titulo" => "Determination of errors in the measurement of radioactivity (IC) and counts per second (GM)" ] 1 => array:2 [ "identificador" => "sec0020" "titulo" => "Response of the detectors to activity, concentration of activity and measurement time" ] 2 => array:2 [ "identificador" => "sec0025" "titulo" => "Cross calibration" ] 3 => array:3 [ "identificador" => "sec0030" "titulo" => "Procedure for the measurement of the radiochemical purity of [Tc]Tc-MDP and [Tc]Tc-MIBI" "secciones" => array:3 [ 0 => array:2 [ "identificador" => "sec0035" "titulo" => "Ascending paper chromatography [Tc]Tc-MDP" ] 1 => array:2 [ "identificador" => "sec0040" "titulo" => "Ascending paper chromatography [Tc]Tc-MIBI" ] 2 => array:2 [ "identificador" => "sec0045" "titulo" => "Partitioning vials" ] ] ] ] ] 6 => array:3 [ "identificador" => "sec0050" "titulo" => "Results" "secciones" => array:5 [ 0 => array:2 [ "identificador" => "sec0055" "titulo" => "Determination of errors" ] 1 => array:2 [ "identificador" => "sec0060" "titulo" => "Uncertainty and measurement time" ] 2 => array:2 [ "identificador" => "sec0065" "titulo" => "Uncertainty and source volume" ] 3 => array:2 [ "identificador" => "sec0070" "titulo" => "Cross calibration" ] 4 => array:2 [ "identificador" => "sec0075" "titulo" => "Control of radiochemical purity" ] ] ] 7 => array:2 [ "identificador" => "sec0080" "titulo" => "Conclusions" ] 8 => array:2 [ "identificador" => "sec0085" "titulo" => "Conflict of interest" ] 9 => array:1 [ "titulo" => "References" ] ] ] "pdfFichero" => "main.pdf" "tienePdf" => true "fechaRecibido" => "2024-01-09" "fechaAceptado" => "2024-03-25" "PalabrasClave" => array:2 [ "en" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Keywords" "identificador" => "xpalclavsec1859357" "palabras" => array:5 [ 0 => "Quality control" 1 => "Radiochemical purity" 2 => "Conventional radiopharmacy" 3 => "Geiger probe" 4 => "Tc radiopharmaceuticals" ] ] ] "es" => array:1 [ 0 => array:4 [ "clase" => "keyword" "titulo" => "Palabras clave" "identificador" => "xpalclavsec1859356" "palabras" => array:5 [ 0 => "Control de calidad" 1 => "Pureza radioquímica" 2 => "Radiofarmacia convencional" 3 => "Sonda Geiger" 4 => "Radiofármacos tecneciados" ] ] ] ] "tieneResumen" => true "resumen" => array:2 [ "en" => array:3 [ "titulo" => "Abstract" "resumen" => "<span id="abst0005" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0010">Background and objectives</span><p id="spar0045" class="elsevierStyleSimplePara elsevierViewall">In a hospital radiopharmacy with 2a operational level, including the preparation of radiopharmaceuticals from prepared and approved reagent kits, it is common to have a single activimeter or dose calibrator for labeling and fractionation, and to perform the quality controls of the <span class="elsevierStyleSup">99m</span>Tc-radiopharmaceuticals. In certain cases, the accumulation of radioactive material or accidental contamination of the work area causes the background to exceed the limits to carry out the radiochemical purity analyses and it is necessary to look for viable alternatives. In this work, a Geiger Müller detector (equipped with a probe for measuring surface contamination) frequently used for radioprotection purposes, was validated as an alternative and its performance was compared against the activimeter for <span class="elsevierStyleSup">99m</span>Tc-radiopharmaceuticals.</p></span> <span id="abst0010" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0015">Materials and methods</span><p id="spar0050" class="elsevierStyleSimplePara elsevierViewall">Using [<span class="elsevierStyleSup">99m</span>Tc]pertechnetate, systematic studies of error analyses and detector response to activity concentration, activity and measurement time were carried out in liquid matrices and in paper. The results were compared against an activimeter calibrated for [<span class="elsevierStyleSup">99m</span>Tc]Tc.</p></span> <span id="abst0015" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0020">Results</span><p id="spar0055" class="elsevierStyleSimplePara elsevierViewall">The developed method was used to determine the radiochemical purity of the compounds [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP and [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI by ascending paper chromatography tests, obtaining comparable values to those measured with an activimeter in the same system (within 1% uncertainty) and using the method of vial partitioning in a dedicated equipment.</p></span> <span id="abst0020" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0025">Conclusions</span><p id="spar0060" class="elsevierStyleSimplePara elsevierViewall">This work demonstrates that a Geiger Müller detector with a probe for measuring surface contamination can be adequately used to replace other equipment in the control of radiochemical purity in the hospital radiopharmacy.</p></span>" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "abst0005" "titulo" => "Background and objectives" ] 1 => array:2 [ "identificador" => "abst0010" "titulo" => "Materials and methods" ] 2 => array:2 [ "identificador" => "abst0015" "titulo" => "Results" ] 3 => array:2 [ "identificador" => "abst0020" "titulo" => "Conclusions" ] ] ] "es" => array:3 [ "titulo" => "Resumen" "resumen" => "<span id="abst0025" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0035">Antecedentes y objetivo</span><p id="spar0065" class="elsevierStyleSimplePara elsevierViewall">En los laboratorios de radiofarmacia hospitalaria de nivel operacional 2a, con preparación de radiofármacos a partir de kits liofilizados sellados, es frecuente que se disponga de un único activímetro o calibrador de dosis para la marcación, fraccionamiento y realización de controles de calidad de radiofármacos marcados con <span class="elsevierStyleSup">99m</span>Tc. En ciertos casos, la acumulación de material radiactivo o la contaminación accidental del área de trabajo hacen que el fondo supere los límites para realizar los controles de calidad de pureza radioquímica y es necesario buscar alternativas viables. En este trabajo se validó como alternativa el uso de un detector Geiger Müller (con sonda para medición de contaminación superficial) utilizado frecuentemente para fines de radioprotección y se comparó su rendimiento contra el activímetro, en radiofármacos tecneciados.</p></span> <span id="abst0030" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0040">Materiales y métodos</span><p id="spar0070" class="elsevierStyleSimplePara elsevierViewall">Utilizando [<span class="elsevierStyleSup">99m</span>Tc]pertecnetato se realizaron estudios sistemáticos de análisis de errores y de respuesta del detector ante concentración de actividad, determinación de actividad y tiempo de medición, en matrices líquidas y de papel. Se compararon los resultados contra un activímetro calibrado para [<span class="elsevierStyleSup">99m</span>Tc]Tc.</p></span> <span id="abst0035" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0055">Resultados</span><p id="spar0075" class="elsevierStyleSimplePara elsevierViewall">Se utilizó el método desarrollado para determinar la pureza radioquímica de los compuestos [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP y [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI por prueba de cromatografía de papel ascendente, obteniendo valores comparables a los medidos con un activímetro en el mismo sistema (dentro del ± 1% de incerteza) y mediante el método de frascos de partición en un aparato dedicado para tal fin.</p></span> <span id="abst0040" class="elsevierStyleSection elsevierViewall"><span class="elsevierStyleSectionTitle" id="sect0060">Conclusiones</span><p id="spar0080" class="elsevierStyleSimplePara elsevierViewall">Este trabajo demuestra que un detector Geiger Müller con sonda para medición de contaminación superficial puede ser adecuadamente utilizado para reemplazar otros equipos en el control de pureza radioquímica en la radiofarmacia hospitalaria.</p></span>" "secciones" => array:4 [ 0 => array:2 [ "identificador" => "abst0025" "titulo" => "Antecedentes y objetivo" ] 1 => array:2 [ "identificador" => "abst0030" "titulo" => "Materiales y métodos" ] 2 => array:2 [ "identificador" => "abst0035" "titulo" => "Resultados" ] 3 => array:2 [ "identificador" => "abst0040" "titulo" => "Conclusiones" ] ] ] ] "NotaPie" => array:2 [ 0 => array:3 [ "etiqueta" => "1" "nota" => "<p class="elsevierStyleNotepara" id="npar0001">Current address: INVAP S.E. Comte. Luis Piedrabuena 4960, San Carlos de Bariloche, Provincia de Río Negro, Argentina (CP 8400).</p>" "identificador" => "fn0001" ] 1 => array:3 [ "etiqueta" => "2" "nota" => "<p class="elsevierStyleNotepara" id="npar0005">Current address: Laboratorio Austral, Olascoaga 951, Provincia de Neuquén, Argentina (CP8300).</p>" "identificador" => "fn0005" ] ] "multimedia" => array:7 [ 0 => array:8 [ "identificador" => "fig0005" "etiqueta" => "Fig. 1" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr1.jpeg" "Alto" => 1461 "Ancho" => 2508 "Tamanyo" => 184700 ] ] "detalles" => array:1 [ 0 => array:3 [ "identificador" => "at0005" "detalle" => "Fig. " "rol" => "short" ] ] "descripcion" => array:1 [ "en" => "<p id="spar0005" class="elsevierStyleSimplePara elsevierViewall">Systems and fractions for the mobile phase used in the determination by ascending paper chromatography of the radiochemical purity of: (A) [<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP (<span class="elsevierStyleSup">99m</span>Tc-HyC: hydrolyzed and colloidal technetium, <span class="elsevierStyleSup">99m</span>Tc-free: [<span class="elsevierStyleSup">99m</span>Tc]pertechnetate. (B) [<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI.</p>" ] ] 1 => array:8 [ "identificador" => "fig0010" "etiqueta" => "Fig. 2" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr2.jpeg" "Alto" => 1770 "Ancho" => 2175 "Tamanyo" => 480067 ] ] "detalles" => array:1 [ 0 => array:3 [ "identificador" => "at0010" "detalle" => "Fig. " "rol" => "short" ] ] "descripcion" => array:1 [ "en" => "<p id="spar0010" class="elsevierStyleSimplePara elsevierViewall">Percentage of dispersion with respect to the nominal value of the number of counts per second (corrected for decay) measured in the GM detector.</p>" ] ] 2 => array:8 [ "identificador" => "fig0015" "etiqueta" => "Fig. 3" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr3.jpeg" "Alto" => 1187 "Ancho" => 1508 "Tamanyo" => 149658 ] ] "detalles" => array:1 [ 0 => array:3 [ "identificador" => "at0015" "detalle" => "Fig. " "rol" => "short" ] ] "descripcion" => array:1 [ "en" => "<p id="spar0015" class="elsevierStyleSimplePara elsevierViewall">Behavior of the measurement of activity (IC) and counts per second (GM) of a source of nominal activity of 3.7 MBq and 18.5 MBq in different volumes of between 25 and 500 μl.</p>" ] ] 3 => array:8 [ "identificador" => "fig0020" "etiqueta" => "Fig. 4" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr4.jpeg" "Alto" => 1651 "Ancho" => 1675 "Tamanyo" => 100468 ] ] "detalles" => array:1 [ 0 => array:3 [ "identificador" => "at0020" "detalle" => "Fig. " "rol" => "short" ] ] "descripcion" => array:1 [ "en" => "<p id="spar0020" class="elsevierStyleSimplePara elsevierViewall">Effect of the hardening of the spectrum caused by the increase in volume of the source and self-attenuation.</p>" ] ] 4 => array:8 [ "identificador" => "fig0025" "etiqueta" => "Fig. 5" "tipo" => "MULTIMEDIAFIGURA" "mostrarFloat" => true "mostrarDisplay" => false "figura" => array:1 [ 0 => array:4 [ "imagen" => "gr5.jpeg" "Alto" => 2346 "Ancho" => 1675 "Tamanyo" => 340686 ] ] "detalles" => array:1 [ 0 => array:3 [ "identificador" => "at0025" "detalle" => "Fig. " "rol" => "short" ] ] "descripcion" => array:1 [ "en" => "<p id="spar0025" class="elsevierStyleSimplePara elsevierViewall">Line of calibration between counts per second in the GM detector and the line and the activity in MBq. All the data are corrected for decay time and background. (A) Samples in liquid matrix. Activities dissolved in volumes between 25 and 500 μl of saline solution. The measurement time in the GM detector was 60 s. (B) Samples inoculated on paper. The error bars represent the standard deviation on averaging 12 measurements in the GM and 3 in the IC.</p>" ] ] 5 => array:8 [ "identificador" => "tbl0005" "etiqueta" => "Table 1" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "detalles" => array:1 [ 0 => array:3 [ "identificador" => "at0030" "detalle" => "Table " "rol" => "short" ] ] "tabla" => array:1 [ "tablatextoimagen" => array:2 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " colspan="6" align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col" style="border-bottom: 2px solid black">Liquid matrix — 2 ml microtubes</th></tr><tr title="table-row"><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " colspan="6" align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col" style="border-bottom: 2px solid black">Concentration of MBq/ml activity (mCi/ml = μCi/μl)</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">Activity volume \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.925 MBq (25 μCi) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">1.85 MBq (50 μCi) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">3.7 MBq (100 μCi) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">9.25 MBq (250 μCi) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">18.5 MBq (500 μCi) \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">25 μl \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">37 (1) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">74 (2) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">148 (4) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">370 (10) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">740 (20) \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">50 μl \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">19 (0.5) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">37 (1) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">74 (2) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">185 (5) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">370 (10) \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">100 μl \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">9 (0.25) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">19 (0.5) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">37 (1)<span class="elsevierStyleBold">*</span> \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">93 (2.5) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">185 (5) \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">250 μl \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">4 (0.1) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">7 (0.2) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">15 (0.4) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">37 (1) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">74 (2) \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">500 μl \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">2 (0.05) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">4 (0.1) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">7 (0.2) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">19 (0.5) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">37 (1) \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab3617238.png" ] ] 1 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " colspan="13" align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col" style="border-bottom: 2px solid black">Paper matrix — Whatman N° 1 filter paper</th></tr><tr title="table-row"><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " colspan="13" align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col" style="border-bottom: 2px solid black">Activity MBq (μCi)</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.009 (0.25) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.019 (0.5) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.037 (1) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.046 (1.25) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.074 (2) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.093 (2.5) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.185 (5) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.370 (10) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.463 (12.5) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.740 (20) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">0.925 (25) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">1.850 (50) \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">3.700 (100) \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab3617239.png" ] ] ] ] "descripcion" => array:1 [ "en" => "<p id="spar0030" class="elsevierStyleSimplePara elsevierViewall">Nominal concentration values (kBq/μl), volume (μl) and radioactivity (kBq) of the samples used for the analysis of errors and response to the concentration of activity and measurement time. Ten examples of the sample marked with * were made.</p>" ] ] 6 => array:8 [ "identificador" => "tbl0010" "etiqueta" => "Table 2" "tipo" => "MULTIMEDIATABLA" "mostrarFloat" => true "mostrarDisplay" => false "detalles" => array:1 [ 0 => array:3 [ "identificador" => "at0035" "detalle" => "Table " "rol" => "short" ] ] "tabla" => array:2 [ "leyenda" => "<p id="spar0040" class="elsevierStyleSimplePara elsevierViewall">CM: Geiger Müller detector; IC: ionization chamber.</p>" "tablatextoimagen" => array:1 [ 0 => array:2 [ "tabla" => array:1 [ 0 => """ <table border="0" frame="\n \t\t\t\t\tvoid\n \t\t\t\t" class=""><thead title="thead"><tr title="table-row"><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " colspan="2" align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col" style="border-bottom: 2px solid black">Separation technique</th><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " colspan="2" align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col" style="border-bottom: 2px solid black">Paper chromatography</th><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col">Vial partition \t\t\t\t\t\t\n \t\t\t\t\t\t</th></tr><tr title="table-row"><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " colspan="2" align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col" style="border-bottom: 2px solid black">Measurement technique</th><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col" style="border-bottom: 2px solid black">GM \t\t\t\t\t\t\n \t\t\t\t\t\t</th><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col" style="border-bottom: 2px solid black">IC \t\t\t\t\t\t\n \t\t\t\t\t\t</th><th class="td" title="\n \t\t\t\t\ttable-head\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t" scope="col" style="border-bottom: 2px solid black">BAC-MT® \t\t\t\t\t\t\n \t\t\t\t\t\t</th></tr></thead><tbody title="tbody"><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead rowgroup " rowspan="2" align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">MDP</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">[<span class="elsevierStyleSup">99m</span>Tc]Tc-impurities \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(3.3 ± 0.2)% \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(2.5 ± 0.2)% \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(0 ± 1)% \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">[<span class="elsevierStyleSup">99m</span>Tc]Tc-MDP \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(96.7 ± 0.2)% \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(97.5 ± 0.2)% \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(100 ± 1)% \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead rowgroup " rowspan="2" align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">MIBI</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">[<span class="elsevierStyleSup">99m</span>Tc]Tc-impurities \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(0.077 ± 0.005)% \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(0.032 ± 0.002)% \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(0 ± 1)% \t\t\t\t\t\t\n \t\t\t\t</td></tr><tr title="table-row"><td class="td-with-role" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t ; entry_with_role_rowhead " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">[<span class="elsevierStyleSup">99m</span>Tc]Tc-MIBI \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(99.923 ± 0.005)% \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(99.968 ± 0.002)% \t\t\t\t\t\t\n \t\t\t\t</td><td class="td" title="\n \t\t\t\t\ttable-entry\n \t\t\t\t " align="left" valign="\n \t\t\t\t\ttop\n \t\t\t\t">(100 ± 1)% \t\t\t\t\t\t\n \t\t\t\t</td></tr></tbody></table> """ ] "imagenFichero" => array:1 [ 0 => "xTab3617240.png" ] ] ] ] "descripcion" => array:1 [ "en" => "<p id="spar0035" class="elsevierStyleSimplePara elsevierViewall">Control of radiochemical purity obtained with the chromatographic method using both detectors (GM and IC) and with the vial partitioning methods using the BAC MT® equipment. The uncertainties for the paper chromatography methods were calculated by the method of partial derivatives. The uncertainty for the vial partitioning method was considered as that shown by the equipment.</p>" ] ] ] "bibliografia" => array:2 [ "titulo" => "References" "seccion" => array:1 [ 0 => array:2 [ "identificador" => "bibs0005" "bibliografiaReferencia" => array:9 [ 0 => array:3 [ "identificador" => "bib0005" "etiqueta" => "1" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Radiopharmaceutical quality control" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:1 [ 0 => "T.B. Saleh" ] ] ] ] ] "host" => array:2 [ 0 => array:1 [ "Libro" => array:6 [ "titulo" => "Basic sciences of nuclear medicine" "fecha" => "2010" "paginaInicial" => "55" "paginaFinal" => "64" "editorial" => "Springer" "editorialLocalizacion" => "Berlin Heidelberg" ] ] 1 => array:1 [ "WWW" => array:1 [ "link" => "https://doi.org/10.1007/978-3-540-85962-8_4" ] ] ] ] ] ] 1 => array:3 [ "identificador" => "bib0010" "etiqueta" => "2" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Quality assurance and quality control of Tc-99m radiopharmaceuticals" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:2 [ 0 => "V. Loveless" 1 => "S.H. Morgan" ] ] ] ] ] "host" => array:1 [ 0 => array:2 [ "doi" => "10.1007/978-3-030-65245-6_6" "LibroEditado" => array:3 [ "editores" => "M.M.Khalil" "titulo" => "Basic sciences of nuclear medicine" "serieFecha" => "2021" ] ] ] ] ] ] 2 => array:3 [ "identificador" => "bib0015" "etiqueta" => "3" "referencia" => array:1 [ 0 => array:2 [ "contribucion" => array:1 [ 0 => array:2 [ "titulo" => "Quality control methods of 99mTc pharmaceuticals" "autores" => array:1 [ 0 => array:2 [ "etal" => false "autores" => array:6 [ 0 => "C. Decristoforo" 1 => "I. Zolle" 2 => "F. Rakiás" 3 => "J. Imre" 4 => "G. Jánoki" 5 => "S.R. 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A technologist’s guide" "serieFecha" => "2016" ] ] ] ] ] ] ] ] ] ] ] "idiomaDefecto" => "en" "url" => "/22538089/0000004300000003/v3_202408071237/S2253808924000168/v3_202408071237/en/main.assets" "Apartado" => array:4 [ "identificador" => "7926" "tipo" => "SECCION" "en" => array:2 [ "titulo" => "Original articles" "idiomaDefecto" => true ] "idiomaDefecto" => "en" ] "PDF" => "https://static.elsevier.es/multimedia/22538089/0000004300000003/v3_202408071237/S2253808924000168/v3_202408071237/en/main.pdf?idApp=UINPBA00004N&text.app=https://www.elsevier.es/" "EPUB" => "https://multimedia.elsevier.es/PublicationsMultimediaV1/item/epub/S2253808924000168?idApp=UINPBA00004N" ]
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