Ionizing radiation metrology at the service of health: quality control of radiopharmaceutical dose calibrators in nuclear medicine unit -accurarcy, reproducibility and linearity tests (original) (raw)
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International Journal of Advanced Research (IJAR), 2019
The aim of this study is to evaluate and compare the performance of two dose calibrators which are used in Nuclear Medicine Center by standard tests accuracy, constancy, linearity and geometry. To check the performance status of the dose calibrators the activity of radiopharmaceuticals must be accurately known before administered to the patients. Two dose calibrators of Institute Nuclear Medicine and Allied Sciences, Dhaka (Capintec, Inc.,Model no. CRC 25R and Veenstra , model no. VDC 404) performances were compared in accordance with varying geometry because most common measurement geometries utilized in clinical practice are glass vials, solid capsules and various types of plastic syringes. Vials and syringes filling volumes can be widely different, according to clinical needs. It was found that the measurement activity readings of one of these two dose calibrator, VDC-404, showed slightly deviating from accurate value because readings might be affected by the frequent change in background count. The results of the quality control (QC) tests revealed that the parameters that were traced for both dose calibrators were within the limits of the international standards, ?5%. Regular QC should cover precision, accuracy, linearity, and geometry of instrument, according to IAEA standards, e.g. (IAEA TECDOC-602 and 1599), that will guarantee to assure the proper practice of nuclear medicine diagnosis. It is also vital to fulfill radiation protection requirements as well as successful therapies and good quality image production in nuclear medicine practices.
Comparative Assesment of Dose Calibrators Used in Nuclear Medicine
Middle East Journal of Science, 2020
Dose calibrators are used to measure the amount of radioactive to be given to the patient. It is necessary to determine the correct dose and measure the amount of radioactive material with the least possible error. To minimize these potential errors, quality control (QC) tests should be carried out periodically according to the United States Nuclear Regulatory Authority (NRC). ATOM LAB 400 (serial number:11070208) and 500 (serial number: 15091215) dose calibrators that are actively used in our clinic were used. The aim of this study is to compare with another recently calibrated dose calibrator to verify the dose calibrator that needs to be updated is working properly. QC tests were performed on both dose calibrators. Test results of the currently certified dose calibrator and ATOM LAB 400 dose calibrator whose certificate will be updated were found to be compatible with each other. The tests performed on both dose calibrators remained with the error limits. The calibration certificate of the ATOM LAB 400 calibrator has been updated in accordance with NRC protocol.
Physica Medica, 2019
Reliable quantification of radioactivity in nuclear medicine is becoming increasingly important in various therapeutic applications requiring a high accuracy of nuclear medicine measuring equipment, such as radionuclide calibrators. In this study the accuracy of four different radionuclide calibrators was assessed for 99m Tc, 111 In, 68 Ga and 18 F for measurement geometries clinically used. Methods: Syringes and vials were prepared with a reference activity using a stock solution of which the activity concentration was determined using gamma-ray spectroscopy. The accuracy of four different radionuclide calibrator systems, ISOMED 2000, ISOMED 2010, VIK-202 and Capintec CRC-25R, was assessed by comparing the measured activity to the reference activity. Results: Deviations in measured activity from reference values were found up to 12.5%, 32.0%, 29.0% and 12.6% for 99m Tc, 111 In, 68 Ga and 18 F, respectively. For 68 Ga all radionuclide calibrators systematically overestimated the activity by 10-20%. For 111 In, large differences in activity measurements were observed between different source geometries, in particular between syringes and vials. Deviations between radionuclide calibrator systems were found up to 11.8%, 44.4%, 14.4% and 8.7% for 99m Tc, 111 In, 68 Ga and 18 F, respectively. When comparing similar syringe types of different brands filled with identical stock solution volume, deviations up to 1.8%, 5.8%, 10.2% and 3.2% were found for 99m Tc, 111 In, 68 Ga and 18 F. Conclusion: Substantial deviations in measured activity were found for all radionuclides and radionuclide calibrators, which may result in erroneous activity dosing and image quantification. This underlines the importance of thorough validation of radionuclide calibrators for all measurement geometries and radionuclides clinically used.
Radionuclide calibrator comparisons and quality improvement in nuclear medicine
Applied Radiation and Isotopes, 2008
The traceability of activity measurements performed during the development phase of the radiopharmaceutical and in its clinical application is essential for establishing the comparability of clinical results reported in the nuclear medicine field. This paper presents and discusses the evaluation over time of the quality of activity measurement results obtained in Cuban nuclear medicine, on the basis of statistical samples taken during the radionuclide calibrator comparison program. An attempt is also made to evaluate the role played by such comparisons in quality measurement improvement in nuclear medicine, on the basis of results obtained in a number of countries and published by several authors over a period of time. Specifically, improvements of the measurement performance over time assessed by such exercises were found dissimilar in magnitudes for different countries. Two phases could be distinguished in the improvement process over time. Firstly, a fast improvement can be obtained resulting from the improvement in measurement accuracy of devices. After that, the achievement of new and sustained improvements goes slowly and requires an application of quality assurance programs where the qualification upgrading of personnel become an essential point.
Assessment of 99mTc Dose Calibrator Performance in Nuclear Medicine Department
Nuclear medicine uses many different radioactive isotopes for radiation diagnostics and for therapy. The amount of radioactivity has to be determined exactly before it is applied to a patient. The Dose calibrators have to measure the radioactivity of gamma and beta with different energies precisely for high quality imaging and for applying the right amount of radiation to treat disease. This study was carried out to assess the performance of dose calibrators which work in nuclear medicine departments in Khartoum state. Two departments were included in this study, Radiation and isotopes center of Khartoum (RICK) and Elnileen medical diagnostic center. Four quality control tests were carried out using two standard Radionuclides, 137Cs and 57Co, which were accuracy, constancy, linearity and geometry. All results that obtained from the study has been compared with the international standard (±5%) and the results showed that all dose calibrators has good performance and there is no need for any correction tables or factors or maintenance.
Comparative measurements in dose calibrators and a gamma-ray spectrometer
Applied Radiation and Isotopes, 2010
Specific activity results of 51 Cr, 67 Ga, 99m Tc and 201 Tl radioactive solutions, measured in different dose calibrators located at nuclear medicine services and in a calibrated HPGe gamma spectrometer, were compared. The HPGe spectrometer was calibrated in a well defined geometry by means of 60 Co, 133 Ba, 152 Eu, 166m Ho and 241 Am sources, previously standardized in a 4pb À g coincidence system. Despite the observed differences, the results may be accepted within the 10% uncertainty range, established by Brazilian regulatory standards.
World Journal of Nuclear Medicine, 2015
Dose calibrator linearity testing is indispensable for evaluating the capacity of this equipment in measuring radioisotope activities at different magnitudes, a fundamental aspect of the daily routine of a nuclear medicine department, and with an impact on patient exposure. The main aims of this study were to evaluate the feasibility of substituting the radioisotope Fluorine-18 ( 18 F) with Technetium-99m ( 99m Tc) in this test, and to indicate it with the lowest operational cost. The test was applied with sources of 99m Tc (62 GBq) and 18 F (12 GBq), the activities of which were measured at different times, with the equipment preadjusted to measuring sources of 99m Tc, 18 F, Gallium-67 ( 67 Ga), and Iodine-131 ( 131 I). Over time, the average deviation between measured and expected activities from 99m Tc and 18 F were, respectively, 0.56 (±1.79)% and 0.92 (±1.19)%. The average ratios for 99 m Tc source experimental activity, when measured with the equipment adjusted for measuring 18 F, 67 Ga, and 131 I sources, in real values, were, respectively, 3.42 (±0.06), 1.45 (±0.03), and 1.13 (±0.02), and those for the 18 F source experimental activity, measured through adjustments of 99m Tc, 67 Ga, and 131 I, were, respectively, 0.295 (±0.004), 0.335 (±0.007), and 0.426 (±0.006). The adjustment of a simple exponential function for describing 99m Tc and 18 F experimental activities facilitated the calculation of the physical half-lives of the radioisotopes, with a difference of about 1% in relation to the values described in the literature. Linearity test results, when using 99m Tc, through being compatible with those acquired with 18 F, imply the possibility of using both radioisotopes during linearity testing. Nevertheless, this information, along with the high potential of exposure and the high cost of 18 F, implies that 99m Tc should preferably be employed for linearity testing in clinics that normally use 18 F, without the risk of prejudicing either the procedure itself or the guarantee of a high-quality nuclear medicine service.
Brazilian Journal of Radiation Sciences, 2019
Activimeters (or dose calibrators) are essential instruments to verify activity of radiopharmaceutical after production and also before the dose administration in humans or animals for molecular imaging. The efficiency and safety measurements depend on, beside other factors, constancy tests and quality assurance. Thereby, the aim of this work was to perform constancy tests and quality assurance in the activimeters of the UPPR/CDTN, based on the CNEN-NN 3.05 Brazilian standard and the manufacturer's manual. Physical inspection, auto zero, background check, camera voltage, data check and constancy test were done. In addition, accuracy and precision tests were performed using a set of standard certified radioactive sources (57Co, 133Ba and 137Cs), according to the CNEN NN 3.05 Brazilian standard. Linearity test was also performed to evaluate the response of the equipment in over the entire range of activities used in routine. The equipments are periodically submitted to the quality...
Applied Radiation and …, 2010
The activity of radiopharmaceuticals in nuclear medicine is measured before patient injection with radionuclide calibrators. In Switzerland, the general requirements for quality controls are defined in a federal ordinance and a directive of the Federal Office of Metrology (METAS) which require each instrument to be verified. A set of three gamma sources (Co-57, Cs-137 and Co-60) is used to verify the response of radionuclide calibrators in the gamma energy range of their use. A beta source, a mixture of 90 Sr and 90 Y in secular equilibrium, is used as well. Manufacturers are responsible for the calibration factors. The main goal of the study was to monitor the validity of the calibration factors by using two sources: a 90 Sr/ 90 Y source and a 18 F source. The three types of commercial radionuclide calibrators tested do not have a calibration factor for the mixture but only for 90 Y. Activity measurements of a 90 Sr/ 90 Y source with the 90 Y calibration factor are performed in order to correct for the extracontribution of 90 Sr. The value of the correction factor was found to be 1.113 whereas Monte Carlo simulations of the radionuclide calibrators estimate the correction factor to be 1.117. Measurements with 18 F sources in a specific geometry are also performed. Since this radionuclide is widely used in Swiss hospitals equipped with PET and PET-CT, the metrology of the 18 F is very important. The 18 F response normalized to the 137 Cs response shows that the difference with a reference value does not exceed 3% for the three types of radionuclide calibrators.