Pub Date : 2024-08-28DOI: 10.1016/j.radmeas.2024.107277
Khaoula Laazouzi , Nícollas Gonçalves Cavedini , Omaima Essaad Belhaj , Maryam Hadouachi , Hamid Boukhal , El mahjoub Chakir , Cristina Maria Moriguchi Jeckel , Ana Maria Marques da Silva , Maikol Salas-Ramirez
Animal models are essential in the development of new radiopharmaceuticals in nuclear medicine, particularly for accurate dose calculation in small animal internal dosimetry. This study presents a comprehensive dataset of S-values for eleven commonly used radionuclides, calculated using the DM_Bra mouse phantom with the GATE Monte Carlo simulation code. To validate our approach, we first compared S-values obtained from the DM_Bra phantom with published values derived from the Digimouse phantom using a Tc-99 m source. The differences between the two phantoms range from 0.68% to 12.45% for self-irradiation and from 0.15% to 4.19% for cross-irradiation when the source is the stomach. These results demonstrate good agreement with reference data, supporting the reliability of our dataset. We then expanded our analysis by generating S-values for additional radionuclides, reflecting their usage in both diagnostic and therapeutic applications. Furthermore, to assess the impact of varying mouse geometries on S-values, the DM_Bra phantom (26.9 g) was rescaled to represent two other mouse sizes (19.6 g and 35.9 g). The statistical uncertainty associated with all these S-values remains below 2%. This study offers a valuable resource for internal dosimetry in mice, providing detailed S-values for a wide range of radionuclides and organ geometries, which can be used in small animal PET and SPECT studies.
动物模型对核医学新放射性药物的开发至关重要,特别是对小动物体内剂量测定的精确剂量计算。本研究介绍了利用 DM_Bra 小鼠模型和 GATE 蒙特卡罗模拟代码计算出的 11 种常用放射性核素的 S 值的综合数据集。为了验证我们的方法,我们首先将从 DM_Bra 体模中获得的 S 值与从 Digimouse 体模中使用 Tc-99 m 源获得的已公布值进行了比较。当放射源为胃时,两个模型之间的自辐射差异从 0.68% 到 12.45%,交叉辐射差异从 0.15% 到 4.19%。这些结果与参考数据非常吻合,证明了我们数据集的可靠性。随后,我们通过生成更多放射性核素的 S 值扩大了分析范围,以反映它们在诊断和治疗中的应用。此外,为了评估不同小鼠几何尺寸对 S 值的影响,我们对 DM_Bra 模体(26.9 克)进行了调整,以代表另外两种尺寸的小鼠(19.6 克和 35.9 克)。与所有这些 S 值相关的统计不确定性仍然低于 2%。这项研究为小鼠体内剂量测定提供了宝贵的资源,为多种放射性核素和器官几何形状提供了详细的 S 值,可用于小动物 PET 和 SPECT 研究。
{"title":"Development and validation of a comprehensive S-value database for small animal internal dosimetry in nuclear medicine using the DM_Bra mouse phantom","authors":"Khaoula Laazouzi , Nícollas Gonçalves Cavedini , Omaima Essaad Belhaj , Maryam Hadouachi , Hamid Boukhal , El mahjoub Chakir , Cristina Maria Moriguchi Jeckel , Ana Maria Marques da Silva , Maikol Salas-Ramirez","doi":"10.1016/j.radmeas.2024.107277","DOIUrl":"10.1016/j.radmeas.2024.107277","url":null,"abstract":"<div><p>Animal models are essential in the development of new radiopharmaceuticals in nuclear medicine, particularly for accurate dose calculation in small animal internal dosimetry. This study presents a comprehensive dataset of S-values for eleven commonly used radionuclides, calculated using the DM_Bra mouse phantom with the GATE Monte Carlo simulation code. To validate our approach, we first compared S-values obtained from the DM_Bra phantom with published values derived from the Digimouse phantom using a Tc-99 m source. The differences between the two phantoms range from 0.68% to 12.45% for self-irradiation and from 0.15% to 4.19% for cross-irradiation when the source is the stomach. These results demonstrate good agreement with reference data, supporting the reliability of our dataset. We then expanded our analysis by generating S-values for additional radionuclides, reflecting their usage in both diagnostic and therapeutic applications. Furthermore, to assess the impact of varying mouse geometries on S-values, the DM_Bra phantom (26.9 g) was rescaled to represent two other mouse sizes (19.6 g and 35.9 g). The statistical uncertainty associated with all these S-values remains below 2%. This study offers a valuable resource for internal dosimetry in mice, providing detailed S-values for a wide range of radionuclides and organ geometries, which can be used in small animal PET and SPECT studies.</p></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142137256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-27DOI: 10.1016/j.radmeas.2024.107279
Engin Aşlar
This study investigates in detail the effects of predose on TL and OSL signals for BeO dosimeters. The TL and OSL signals were deconvoluted to each peak and component. As a result of deconvolution, the variations in the kinetic parameters (E, Tmax, b) for the TL signals and the lifetime values of the OSL signals were investigated. In addition, sensitivity changes according to predose were monitored for each peak and component. Finally, dose response curves were studied using the dose linearity index (f(D)) for each peak and component. Accordingly, the peak structures and kinetic parameters did not change according to the predose for the TL signal, whereas variations in the lifetime values for the OSL signal were observed, especially at the initial dose values (0.1 and 0.2 Gy). There was no change in sensitivity according to the predose for the total area condition although each peak and component exhibited independent behavior. Therefore, TL and OSL signals should be evaluated based on the total area in predose applications. The TL and OSL dose response curves exhibited different behaviors according to predose. TL dose response curves were not affected by the predose except for 1000 Gy, while the OSL dose response curves were affected by the predose considering the total area condition. The possible reason for the differences between the TL and OSL dose response curves is the significant transfer effect in the OSL signal at low doses, which results in greater changes at low doses compared to the TL signal. Also, thermal quenching effects may have resulted in lower intensity in the case of the TL signal. In future studies, preheating tests and thermal quenching corrections on TL peaks at high predoses may increase our understanding of deep trap interactions in BeO dosimeters.
{"title":"Comparative analysis of predose effects on TL and OSL signals in BeO dosimeters","authors":"Engin Aşlar","doi":"10.1016/j.radmeas.2024.107279","DOIUrl":"10.1016/j.radmeas.2024.107279","url":null,"abstract":"<div><p>This study investigates in detail the effects of predose on TL and OSL signals for BeO dosimeters. The TL and OSL signals were deconvoluted to each peak and component. As a result of deconvolution, the variations in the kinetic parameters (<em>E, T</em><sub><em>max</em></sub><em>, b</em>) for the TL signals and the lifetime values of the OSL signals were investigated. In addition, sensitivity changes according to predose were monitored for each peak and component. Finally, dose response curves were studied using the dose linearity index <em>(f(D</em>)) for each peak and component. Accordingly, the peak structures and kinetic parameters did not change according to the predose for the TL signal, whereas variations in the lifetime values for the OSL signal were observed, especially at the initial dose values (0.1 and 0.2 Gy). There was no change in sensitivity according to the predose for the total area condition although each peak and component exhibited independent behavior. Therefore, TL and OSL signals should be evaluated based on the total area in predose applications. The TL and OSL dose response curves exhibited different behaviors according to predose. TL dose response curves were not affected by the predose except for 1000 Gy, while the OSL dose response curves were affected by the predose considering the total area condition. The possible reason for the differences between the TL and OSL dose response curves is the significant transfer effect in the OSL signal at low doses, which results in greater changes at low doses compared to the TL signal. Also, thermal quenching effects may have resulted in lower intensity in the case of the TL signal. In future studies, preheating tests and thermal quenching corrections on TL peaks at high predoses may increase our understanding of deep trap interactions in BeO dosimeters.</p></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-26DOI: 10.1016/j.radmeas.2024.107278
A. Grygier, S. Chałupnik
This paper describes a method enabling the measurement of the potential alpha energy concentration (PAEC) of thoron decay products based on the determined concentration of lead 212Pb (T1/2 = 10.64 h) in the air [Lever et al., 2003]. A liquid scintillation spectrometer was used to determine the concentration of the 212Pb isotope, and the sample was taken by pumping air through a filter where thoron decay products were stored. This method can be classified as integrating because the sample takes several hours, and the measurement results in one value for the entire sampling period. Measurements were carried out in laboratory conditions, in a climatic chamber where a constant supply of thoron was maintained, and in environmental conditions, in the basement of the family house and outdoors. Sampling took from 12 to 48 h. This article presents the preliminary results of the study. The obtained results were in the range of 170–195 Bq/m3 in the case of laboratory measurements and from 0.04 to 0.79 Bq/m3 in the case of environmental measurements. Based on the obtained results, the potential alpha energy concentration (PAEC) was calculated. The application of the low-level LS spectrometer allows for the achievement of a lower limit of detection (LLD) at level 0.04–0.05 Bq/m3, while the use of the portable LS spectrometer allows for the measurement of deficient 212Pb concentrations in the range of 0.4–0.5 Bq/m3. The obtained results confirm that the method is suitable for determining the concentration of 212Pb and, consequently, assessing exposure to thoron progeny.
{"title":"The method of Pb-212 measurements in air with the application of the LSC technique","authors":"A. Grygier, S. Chałupnik","doi":"10.1016/j.radmeas.2024.107278","DOIUrl":"10.1016/j.radmeas.2024.107278","url":null,"abstract":"<div><p>This paper describes a method enabling the measurement of the potential alpha energy concentration (PAEC) of thoron decay products based on the determined concentration of lead <sup>212</sup>Pb (T<sub>1/2</sub> = 10.64 h) in the air [Lever et al., 2003]. A liquid scintillation spectrometer was used to determine the concentration of the <sup>212</sup>Pb isotope, and the sample was taken by pumping air through a filter where thoron decay products were stored. This method can be classified as integrating because the sample takes several hours, and the measurement results in one value for the entire sampling period. Measurements were carried out in laboratory conditions, in a climatic chamber where a constant supply of thoron was maintained, and in environmental conditions, in the basement of the family house and outdoors. Sampling took from 12 to 48 h. This article presents the preliminary results of the study. The obtained results were in the range of 170–195 Bq/m<sup>3</sup> in the case of laboratory measurements and from 0.04 to 0.79 Bq/m<sup>3</sup> in the case of environmental measurements. Based on the obtained results, the potential alpha energy concentration (PAEC) was calculated. The application of the low-level LS spectrometer allows for the achievement of a lower limit of detection (LLD) at level 0.04–0.05 Bq/m<sup>3</sup>, while the use of the portable LS spectrometer allows for the measurement of deficient <sup>212</sup>Pb concentrations in the range of 0.4–0.5 Bq/m<sup>3</sup>. The obtained results confirm that the method is suitable for determining the concentration of <sup>212</sup>Pb and, consequently, assessing exposure to thoron progeny.</p></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1350448724002269/pdfft?md5=21db9c90ac51a6ee728a58b6e34e4d33&pid=1-s2.0-S1350448724002269-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142130180","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-26DOI: 10.1016/j.radmeas.2024.107273
Malgorzata M. Kasprzak, Gernot Butterweck, Federico A. Geser, Alberto Stabilini, Malgorzata Sliz, Eduardo G. Yukihara, Sabine Mayer
The Calibration Laboratory of the Paul Scherrer Institute (PSI) is a secondary calibration laboratory accredited by the Swiss Accreditation Service (SAS) in accordance with ISO 17025. It also acts as a verification body authorized by the Swiss Federal Institute of Metrology (METAS). The Laboratory is equipped with X-ray, gamma and neutron irradiation facilities, providing characterized reference radiation fields for gamma 137Cs, 60Co, narrow spectrum X-rays from N-15 to N-300 and neutron radionuclide sources 252Cf, 252Cf (D2O-moderated) and 241Am-Be. The laboratory performs routine calibrations, organizes intercomparison measurements for individual monitoring services in Switzerland, and participates in various research projects, e.g., by performing irradiations in reference fields. For this reason, the proper characterization of reference radiation fields is of utmost importance for ensuring high quality irradiations and calibrations of personal dosemeters and radiation protection instruments. In this contribution, we provide an overview of the irradiation facilities at the Calibration Laboratory at PSI and discuss the challenges of characterizing reference radiation fields. In particular, we will discuss the factors affecting the determination of the distance between the source and irradiated dosemeters and detectors, as well as issues related to 252Cf decay and contribution of 250Cf. We will also demonstrate the use of Monte-Carlo simulations in determining the optimal position of the source and irradiation facility within the irradiation room.
保罗舍勒研究所(PSI)校准实验室是瑞士认可服务机构(SAS)根据 ISO 17025 标准认可的二级校准实验室。它还是瑞士联邦计量研究院 (METAS) 授权的验证机构。实验室配备有 X 射线、伽马射线和中子辐照设施,可提供伽马 137Cs、60Co、从 N-15 到 N-300 的窄谱 X 射线以及中子放射性核素源 252Cf、252Cf(D2O-缓和)和 241Am-Be 的特征参考辐射场。该实验室进行日常校准,为瑞士的个别监测服务组织相互比较测量,并参与各种研究项目,例如在参考场进行辐照。因此,参考辐射场的正确表征对于确保个人剂量计和辐射防护仪器的高质量辐照和校准至关重要。在本文中,我们将概述 PSI 校准实验室的辐照设施,并讨论基准辐射场特性分析所面临的挑战。特别是,我们将讨论影响确定源与辐照剂量计和探测器之间距离的因素,以及与 252Cf 衰减和 250Cf 贡献有关的问题。 我们还将演示使用蒙特卡洛模拟来确定辐照室内源和辐照设施的最佳位置。
{"title":"Overview and current challenges at the Calibration Laboratory of the Paul Scherrer Institute","authors":"Malgorzata M. Kasprzak, Gernot Butterweck, Federico A. Geser, Alberto Stabilini, Malgorzata Sliz, Eduardo G. Yukihara, Sabine Mayer","doi":"10.1016/j.radmeas.2024.107273","DOIUrl":"10.1016/j.radmeas.2024.107273","url":null,"abstract":"<div><p>The Calibration Laboratory of the Paul Scherrer Institute (PSI) is a secondary calibration laboratory accredited by the Swiss Accreditation Service (SAS) in accordance with ISO 17025. It also acts as a verification body authorized by the Swiss Federal Institute of Metrology (METAS). The Laboratory is equipped with X-ray, gamma and neutron irradiation facilities, providing characterized reference radiation fields for gamma <sup>137</sup>Cs, <sup>60</sup>Co, narrow spectrum X-rays from N-15 to N-300 and neutron radionuclide sources <sup>252</sup>Cf, <sup>252</sup>Cf (D2O-moderated) and <sup>241</sup>Am-Be. The laboratory performs routine calibrations, organizes intercomparison measurements for individual monitoring services in Switzerland, and participates in various research projects, e.g., by performing irradiations in reference fields. For this reason, the proper characterization of reference radiation fields is of utmost importance for ensuring high quality irradiations and calibrations of personal dosemeters and radiation protection instruments. In this contribution, we provide an overview of the irradiation facilities at the Calibration Laboratory at PSI and discuss the challenges of characterizing reference radiation fields. In particular, we will discuss the factors affecting the determination of the distance between the source and irradiated dosemeters and detectors, as well as issues related to <sup>252</sup>Cf decay and contribution of <sup>250</sup>Cf. We will also demonstrate the use of Monte-Carlo simulations in determining the optimal position of the source and irradiation facility within the irradiation room.</p></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S135044872400221X/pdfft?md5=5082ce0621515fa238af136532218a91&pid=1-s2.0-S135044872400221X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142083638","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Leakage radiation from X-ray security inspection machines is important, and measurement based on ionization chamber or scintillator detector is widely used. The leakage radiation is closely related to the size and the passing time of the luggage, the lead equivalent, the opening angle of the lead curtain, and the response time of the measuring instrument. To characterize the distribution of leakage radiation from the X-ray security inspection machine accurately, a small-volume CZT(CdZnTe) spectrometer was used to measure the energy spectra at a distance of 5 cm from the surface of the inspection machine. By designing and controlling the opening angle of the lead curtain according to the size of the luggage passing through the entrance and exit, the radiation dose was determined based on the measured energy spectra combined with the G(E)-function method. The results show that the maximum relative deviation between the air kerma rate and the ambient dose equivalent rate calculated by the G(E) function method with the standard dose rate does not exceed ±5%. The maximum relative deviation of the dose rate linear verification in the 137Cs radiation field is less than 2.5%. A calibrated CZT detector was utilized to measure the radiation leakage on the surface of the X-ray security inspection machine. It was discovered that the presence of the luggage items and the opening angle of the lead curtain will increase the leakage radiation dose on the surface of the security inspection machine system. This study provides a new approach for measuring scattered radiation of X-ray security inspection machines.
X 射线安全检查机的泄漏辐射非常重要,基于电离室或闪烁探测器的测量方法被广泛使用。泄漏辐射与行李箱的大小和通过时间、铅当量、铅帘开启角度以及测量仪器的响应时间密切相关。为了准确描述 X 射线安检机泄漏辐射的分布特征,我们使用了小体积 CZT(镉锌碲)光谱仪来测量距离安检机表面 5 厘米处的能谱。根据通过出入口的行李大小设计和控制铅帘的开启角度,根据测量到的能谱结合 G(E)函数法确定辐射剂量。结果表明,用 G(E)函数法计算的空气辐射率和环境剂量当量率与标准剂量率之间的最大相对偏差不超过 ±5%。137Cs 辐射场剂量率线性验证的最大相对偏差小于 2.5%。利用校准过的 CZT 探测器测量 X 射线安检机表面的辐射泄漏。结果发现,行李物品的存在和铅幕的开启角度都会增加安检机系统表面的泄漏辐射剂量。这项研究为测量 X 射线安检机的散射辐射提供了一种新方法。
{"title":"Evaluation of radiation leakage in X-ray security inspection machine using a CZT spectrometer","authors":"Weifeng Zhu , jinjie Wu , Rui Zhao , Xianqiang Tang , Mengyu Li","doi":"10.1016/j.radmeas.2024.107274","DOIUrl":"10.1016/j.radmeas.2024.107274","url":null,"abstract":"<div><p>Leakage radiation from X-ray security inspection machines is important, and measurement based on ionization chamber or scintillator detector is widely used. The leakage radiation is closely related to the size and the passing time of the luggage, the lead equivalent, the opening angle of the lead curtain, and the response time of the measuring instrument. To characterize the distribution of leakage radiation from the X-ray security inspection machine accurately, a small-volume CZT(CdZnTe) spectrometer was used to measure the energy spectra at a distance of 5 cm from the surface of the inspection machine. By designing and controlling the opening angle of the lead curtain according to the size of the luggage passing through the entrance and exit, the radiation dose was determined based on the measured energy spectra combined with the G(E)-function method. The results show that the maximum relative deviation between the air kerma rate and the ambient dose equivalent rate calculated by the G(E) function method with the standard dose rate does not exceed ±5%. The maximum relative deviation of the dose rate linear verification in the <sup>137</sup>Cs radiation field is less than 2.5%. A calibrated CZT detector was utilized to measure the radiation leakage on the surface of the X-ray security inspection machine. It was discovered that the presence of the luggage items and the opening angle of the lead curtain will increase the leakage radiation dose on the surface of the security inspection machine system. This study provides a new approach for measuring scattered radiation of X-ray security inspection machines.</p></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142048666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The aim of this study was to develop an efficient protocol for the commissioning of 1000 radiophotoluminescence dosimeters (RPLDs) for use in postal dosimetry audits in radiotherapy. This involved the determination of correction factors necessary to reduce measurement uncertainty and ensure accurate dose measurements.
Methods
The commissioning process started with the RPLDs subjected to a series of controlled irradiations to determine their individual nominal response. Experiments were also conducted to assess the influence of irradiation position, reading position, and ambient temperature on the dosimeter readings all which were accounted for calculating individual sensitivity correction factors (SCFs) for each dosimeter. Statistical analysis was performed to evaluate the variability of SCFs depending on normalization group. An additional investigation simulating different dosimetry audit batches was conducted to study the effect of SCF variability on dosimetry audit measurements.
Results
The adopted commissioning protocol required irradiation position correction factors (0.990–0.996), readout tray position correction factors (0.992–1.01) and room temperature corrections (∼0.4 % per ° C). This enabled the calculation of SCFs for a batch of 1000 RPLDs and the analysis found the majority of SCFs falling within the range of 0.985–1.015. The standard deviations of the SCF distributions were approximately 1% for all normalization groups. It was observed that SCFs normalized to the entire batch of 1000 dosimeters could be effectively used for smaller audit batches, with an additional uncertainty contribution of up to 0.2%. This minimal increase in uncertainty is acceptable within the context of dosimetry audits.
Conclusions
The developed protocol for commissioning RPLDs provides a reliable method for ensuring accurate dose measurements in postal radiotherapy dosimetry audits. The correction factors applied during the commissioning process were thoroughly described to effectively minimize measurement uncertainty. The findings support the use of SCFs normalized to large dosimeter batches for smaller audit groups, thereby streamlining the dosimetry audit process. Future research should focus on the long-term stability of SCFs to further enhance the reliability of RPLD-based dosimetry audits.
{"title":"An efficient protocol for commissioning radiophotoluminescence dosimeters for radiotherapy dosimetry audits","authors":"Alexis Dimitriadis, Pavel Kazantsev, Egor Titovich, Geraldyne Ule-Duque, Roua Abdulrahim, Talent Magnus, Godfrey Azangwe, Jamema Swamidas","doi":"10.1016/j.radmeas.2024.107268","DOIUrl":"10.1016/j.radmeas.2024.107268","url":null,"abstract":"<div><h3>Purpose</h3><p>The aim of this study was to develop an efficient protocol for the commissioning of 1000 radiophotoluminescence dosimeters (RPLDs) for use in postal dosimetry audits in radiotherapy. This involved the determination of correction factors necessary to reduce measurement uncertainty and ensure accurate dose measurements.</p></div><div><h3>Methods</h3><p>The commissioning process started with the RPLDs subjected to a series of controlled irradiations to determine their individual nominal response. Experiments were also conducted to assess the influence of irradiation position, reading position, and ambient temperature on the dosimeter readings all which were accounted for calculating individual sensitivity correction factors (SCFs) for each dosimeter. Statistical analysis was performed to evaluate the variability of SCFs depending on normalization group. An additional investigation simulating different dosimetry audit batches was conducted to study the effect of SCF variability on dosimetry audit measurements.</p></div><div><h3>Results</h3><p>The adopted commissioning protocol required irradiation position correction factors (0.990–0.996), readout tray position correction factors (0.992–1.01) and room temperature corrections (∼0.4 % per ° C). This enabled the calculation of SCFs for a batch of 1000 RPLDs and the analysis found the majority of SCFs falling within the range of 0.985–1.015. The standard deviations of the SCF distributions were approximately 1% for all normalization groups. It was observed that SCFs normalized to the entire batch of 1000 dosimeters could be effectively used for smaller audit batches, with an additional uncertainty contribution of up to 0.2%. This minimal increase in uncertainty is acceptable within the context of dosimetry audits.</p></div><div><h3>Conclusions</h3><p>The developed protocol for commissioning RPLDs provides a reliable method for ensuring accurate dose measurements in postal radiotherapy dosimetry audits. The correction factors applied during the commissioning process were thoroughly described to effectively minimize measurement uncertainty. The findings support the use of SCFs normalized to large dosimeter batches for smaller audit groups, thereby streamlining the dosimetry audit process. Future research should focus on the long-term stability of SCFs to further enhance the reliability of RPLD-based dosimetry audits.</p></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1350448724002166/pdfft?md5=3d5a1fab4603f295917daa061022a4fd&pid=1-s2.0-S1350448724002166-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142007081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-14DOI: 10.1016/j.radmeas.2024.107271
A. Bianchi , A. Selva , F. Pasquato , M. Rossignoli , A. Minarello , A. Fazzi , V. Conte
Innovative Treatment Planning Systems (TPS) in proton therapy based on a variable radiation quality with depth with respect to the conventional one with a fixed Relative Biological Effectiveness (RBE) of 1.1 are under study. Experimental methods are needed to verify the consistency between what is planned and what is delivered in terms of radiation quality. Microdosimetry studies the stochastics of the energy deposition process at micrometric and sub-micrometric level which is known to be related to the biological effectiveness of ionising radiation fields. For this reason, it is recognised by the scientific community that it is a useful tool to monitor the radiation quality of hadron therapy beams where the effectiveness varies with the penetration depth in patients. Detectors are needed to perform a microdosimetric characterization of a clinical beam and they need to satisfy specific requirements to enter the clinical practice as instruments for the Quality Assurance (QA). With this aim, at the Legnaro National Laboratories of the Italian National Institute for Nuclear Physics (LNL-INFN) a technological transfer project was carried out with the final goal of developing engineered miniaturized Tissue Equivalent Proportional Counters (mini-TEPCs) for clinical applications. This work presents the characterization performed on the new detectors and the results obtained in neutron and proton fields.
{"title":"Microdosimetric measurements for LET monitoring in proton therapy. The development of engineered mini-TEPCs for clinical applications: First results","authors":"A. Bianchi , A. Selva , F. Pasquato , M. Rossignoli , A. Minarello , A. Fazzi , V. Conte","doi":"10.1016/j.radmeas.2024.107271","DOIUrl":"10.1016/j.radmeas.2024.107271","url":null,"abstract":"<div><p>Innovative Treatment Planning Systems (TPS) in proton therapy based on a variable radiation quality with depth with respect to the conventional one with a fixed Relative Biological Effectiveness (RBE) of 1.1 are under study. Experimental methods are needed to verify the consistency between what is planned and what is delivered in terms of radiation quality. Microdosimetry studies the stochastics of the energy deposition process at micrometric and sub-micrometric level which is known to be related to the biological effectiveness of ionising radiation fields. For this reason, it is recognised by the scientific community that it is a useful tool to monitor the radiation quality of hadron therapy beams where the effectiveness varies with the penetration depth in patients. Detectors are needed to perform a microdosimetric characterization of a clinical beam and they need to satisfy specific requirements to enter the clinical practice as instruments for the Quality Assurance (QA). With this aim, at the Legnaro National Laboratories of the Italian National Institute for Nuclear Physics (LNL-INFN) a technological transfer project was carried out with the final goal of developing engineered miniaturized Tissue Equivalent Proportional Counters (mini-TEPCs) for clinical applications. This work presents the characterization performed on the new detectors and the results obtained in neutron and proton fields.</p></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S1350448724002191/pdfft?md5=d70a9414d7c2b88031c0e392751645c6&pid=1-s2.0-S1350448724002191-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142002367","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-13DOI: 10.1016/j.radmeas.2024.107270
Jeppe Brage Christensen , Lily Bossin , Iván Domingo Muñoz , Christina Stengl , José Vedelago , Eduardo Gardenali Yukihara
Optically stimulated luminescence detectors (OSLDs) have been utilized for various dosimetry applications for many years. The use of OSLDs for proton dosimetry began over a decade ago, taking advantage of the correlation between the ionization density of the radiation field and the ratio of intensities of the material’s two emission bands. The correlation allows for determining both linear energy transfer (LET) and dose in proton beams, with corrections for ionization quenching derived from the LET. However, the previous methodology for proton dosimetry and simultaneous LET determination with OSLDs was cumbersome and occasionally associated with large uncertainties, while carbon beam dosimetry posed further challenges due to an elevated LET.
This paper reviews the recent advancements in ion beam dosimetry and LET determination using OSLDs. Employing OSLDs alongside improved, automatized read-out techniques, and the use of other radiation quality metrics than averaged LET, has removed most of the previous obstacles for ion beam dosimetry with OSLDs.
The feasibility of simultaneous LET determination and dosimetry in ion beams is demonstrated through two case studies involving realistic proton and carbon ion therapy scenarios.
光激发发光探测器(OSLD)多年来一直被用于各种剂量测定应用。利用辐射场的电离密度与材料两个发射带的强度比之间的相关性,Al2O3:C 光学激发发光探测器在质子剂量测定中的应用始于十多年前。利用这种相关性可以确定质子束的线性能量传递(LET)和剂量,并根据 LET 得出电离淬灭修正。然而,以前使用 Al2O3:C OSLD 进行质子剂量测定和 LET 同步测定的方法非常繁琐,有时还存在较大的不确定性,而碳束剂量测定则因 LET 的升高而面临更多挑战。采用Al2O3:C,Mg OSLD,同时改进自动读出技术,并使用平均LET以外的其他辐射质量指标,消除了以前使用OSLD进行离子束剂量测定的大部分障碍。
{"title":"Optically stimulated luminescence detectors for LET determination and dosimetry in ion beam therapy","authors":"Jeppe Brage Christensen , Lily Bossin , Iván Domingo Muñoz , Christina Stengl , José Vedelago , Eduardo Gardenali Yukihara","doi":"10.1016/j.radmeas.2024.107270","DOIUrl":"10.1016/j.radmeas.2024.107270","url":null,"abstract":"<div><p>Optically stimulated luminescence detectors (OSLDs) have been utilized for various dosimetry applications for many years. The use of <span><math><mrow><msub><mrow><mtext>Al</mtext></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mtext>O</mtext></mrow><mrow><mn>3</mn></mrow></msub><mtext>:C</mtext></mrow></math></span> OSLDs for proton dosimetry began over a decade ago, taking advantage of the correlation between the ionization density of the radiation field and the ratio of intensities of the material’s two emission bands. The correlation allows for determining both linear energy transfer (LET) and dose in proton beams, with corrections for ionization quenching derived from the LET. However, the previous methodology for proton dosimetry and simultaneous LET determination with <span><math><mrow><msub><mrow><mtext>Al</mtext></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mtext>O</mtext></mrow><mrow><mn>3</mn></mrow></msub><mtext>:C</mtext></mrow></math></span> OSLDs was cumbersome and occasionally associated with large uncertainties, while carbon beam dosimetry posed further challenges due to an elevated LET.</p><p>This paper reviews the recent advancements in ion beam dosimetry and LET determination using OSLDs. Employing <span><math><mrow><msub><mrow><mtext>Al</mtext></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mtext>O</mtext></mrow><mrow><mn>3</mn></mrow></msub><mtext>:C,Mg</mtext></mrow></math></span> OSLDs alongside improved, automatized read-out techniques, and the use of other radiation quality metrics than averaged LET, has removed most of the previous obstacles for ion beam dosimetry with OSLDs.</p><p>The feasibility of simultaneous LET determination and dosimetry in ion beams is demonstrated through two case studies involving realistic proton and carbon ion therapy scenarios.</p></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S135044872400218X/pdfft?md5=eef1b5ef38de505923681638d92ad27e&pid=1-s2.0-S135044872400218X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142048667","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Handling the 252Cf radionuclide source poses a potential hazard of skin surface contamination in case of an unexpected occurrence. Consequently, there is a growing need to establish precise dose conversion coefficients tailored to each type of emitted primary particle and various radionuclides. Nevertheless, the current body of literature does not provide specific data or methodologies for evaluating skin contamination dose and its associated coefficients, particularly with regard to the 252Cf source. Thus, this study aims to quantify the dose rate received by the skin and its associated coefficients after contamination scenario. Utilizing the established MCNPX environment, the Equivalent dose rate and Absorbed dose, along with Skin contamination dose coefficient (SCDC), have been calculated within the skin tissue. Two methodologies, specifically Watt Fission distribution and the Doppler Effect, are proposed to analyze particle spectra within skin phantom, enabling the calculation of Equivalent dose rate. In accordance with ICRP recommendations regarding the optimal depth for assessing skin doses, the designated scoring volume within the skin is located between depths of 50–100 μm. This volume is tasked with evaluating the dose. The SCDC results were entirely consistent with previously published data from MCNPX, with statistical uncertainties of less than 15%, demonstrating the efficacy of the methodologies employed in this study. This research presents an innovative method for generating data related to skin contamination doses. The novel outcomes in the current research facilitate the assessment of skin dose contamination for the targeted radionuclides and radiotherapy purposes due to staff oversight and radiobiological effects.
{"title":"Assessment of the skin contamination dose coefficients for 252Cf radionuclide: Monte Carlo approach","authors":"Roya Boudaghi Malidarreh , A.M.A. Mostafa , Shams A.M. Issa , Hesham M.H. Zakaly","doi":"10.1016/j.radmeas.2024.107269","DOIUrl":"10.1016/j.radmeas.2024.107269","url":null,"abstract":"<div><p>Handling the <sup>252</sup>Cf radionuclide source poses a potential hazard of skin surface contamination in case of an unexpected occurrence. Consequently, there is a growing need to establish precise dose conversion coefficients tailored to each type of emitted primary particle and various radionuclides. Nevertheless, the current body of literature does not provide specific data or methodologies for evaluating skin contamination dose and its associated coefficients, particularly with regard to the <sup>252</sup>Cf source. Thus, this study aims to quantify the dose rate received by the skin and its associated coefficients after contamination scenario. Utilizing the established MCNPX environment, the Equivalent dose rate and Absorbed dose, along with Skin contamination dose coefficient (SCDC), have been calculated within the skin tissue. Two methodologies, specifically Watt Fission distribution and the Doppler Effect, are proposed to analyze particle spectra within skin phantom, enabling the calculation of Equivalent dose rate. In accordance with ICRP recommendations regarding the optimal depth for assessing skin doses, the designated scoring volume within the skin is located between depths of 50–100 μm. This volume is tasked with evaluating the dose. The SCDC results were entirely consistent with previously published data from MCNPX, with statistical uncertainties of less than 15%, demonstrating the efficacy of the methodologies employed in this study. This research presents an innovative method for generating data related to skin contamination doses. The novel outcomes in the current research facilitate the assessment of skin dose contamination for the targeted radionuclides and radiotherapy purposes due to staff oversight and radiobiological effects.</p></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142012215","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-10DOI: 10.1016/j.radmeas.2024.107266
Fillipe M. de Jesus , Luciana T. Campos , Simone K. Renha , Priscila M.D.S. Dias , Leonardo D.C. Pacífico , Samara C.F. Machado , Vitor M. Sardenberg , Ricardo T. Lopes , Luís A.G. Magalhães
Objective
To investigate the consistency of the recommended methodology, we analyzed the dosimetric results obtained for each setup beam shaping filter and tube voltage and evaluated the uncertainty associated with the full dose measurement process.
Methods
A 300-mm PTIC was used to validate the results obtained with the 100-mm PTIC. Considering the other dosimetric parts, a cylindrical 160-mm diameter PMMA phantom and a cylindrical 320-mm diameter PMMA phantom were also used in the experimental protocol.
Results
For the lowest and highest tube voltages available, the CTDIair,160 values obtained by 1-step dosimetry with the 300-mm PTIC were greater than the respective values obtained by 2- and 3-step dosimetry with the 100-mm PTIC.
Conclusion
This study established that careful positioning of the 100-mm PTIC in 2 or 3 steps, as well as proper execution of the other dosimetric parts recommended by the IAEA, represents a validated approach within up to 20% uncertainty for wide cone beam CT dosimetry.
{"title":"Wide cone beam CT dosimetry: Analysis of results and uncertainty evaluation","authors":"Fillipe M. de Jesus , Luciana T. Campos , Simone K. Renha , Priscila M.D.S. Dias , Leonardo D.C. Pacífico , Samara C.F. Machado , Vitor M. Sardenberg , Ricardo T. Lopes , Luís A.G. Magalhães","doi":"10.1016/j.radmeas.2024.107266","DOIUrl":"10.1016/j.radmeas.2024.107266","url":null,"abstract":"<div><h3>Objective</h3><p>To investigate the consistency of the recommended methodology, we analyzed the dosimetric results obtained for each setup beam shaping filter and tube voltage and evaluated the uncertainty associated with the full dose measurement process.</p></div><div><h3>Methods</h3><p>A 300-mm PTIC was used to validate the results obtained with the 100-mm PTIC. Considering the other dosimetric parts, a cylindrical 160-mm diameter PMMA phantom and a cylindrical 320-mm diameter PMMA phantom were also used in the experimental protocol.</p></div><div><h3>Results</h3><p>For the lowest and highest tube voltages available, the CTDI<sub>air,160</sub> values obtained by 1-step dosimetry with the 300-mm PTIC were greater than the respective values obtained by 2- and 3-step dosimetry with the 100-mm PTIC.</p></div><div><h3>Conclusion</h3><p>This study established that careful positioning of the 100-mm PTIC in 2 or 3 steps, as well as proper execution of the other dosimetric parts recommended by the IAEA, represents a validated approach within up to 20% uncertainty for wide cone beam CT dosimetry.</p></div>","PeriodicalId":21055,"journal":{"name":"Radiation Measurements","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141978156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}