TY - JOUR
T1 - Organ doses evaluation for chest computed tomography procedures with TL dosimeters
T2 - Comparison with Monte Carlo simulations
AU - Giansante, Louise
AU - Martins, Juliana C.
AU - Nersissian, Denise Y.
AU - Kiers, Karen C.
AU - Kay, Fernando Uliana
AU - Sawamura, Marcio V.Y.
AU - Lee, Choonsik
AU - Gebrim, Eloisa M.M.S.
AU - Costa, Paulo R.
N1 - Funding Information:
São Paulo Research Foundation (FAPESP), Grant/Award Number: 2013/09596-3 and 2010/12237-7; National Council of Technological and Scientific Development (CNPq), Grant/Award Number: 132554/ 2015-1 and 309745/2015-2; Joint CNPq/ FAPESP INCT Project, Grant/Award Number: 573659/2008-7
Funding Information:
This research project was approved to be conducted at InRad under the research protocol CAAE 55420616.3.0000.0068. This work was partially supported by the São Paulo Research Foundation — FAPESP (grants 2013/09596‐3 and 2010/12237‐7) and by the National Council of Technological and Scientific Development — CNPq (grants 132554/ 2015‐1 and 309745/2015‐2), in addition to the joint CNPq/FAPESP INCT project — “Metrology of ionizing radiation in medicine” (grant 573659/2008-7). The authors also thank the IAEA: this research was carried out as part of the IAEA CRP E2.40.20 entitled “Evaluation and Optimization of Pediatric Imaging” (contract number 19047).
Publisher Copyright:
© 2018 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.
PY - 2019/1
Y1 - 2019/1
N2 - Purpose: To evaluate organ doses in routine and low-dose chest computed tomography (CT) protocols using an experimental methodology. To compare experimental results with results obtained by the National Cancer Institute dosimetry system for CT (NCICT) organ dose calculator. To address the differences on organ dose measurements using tube current modulation (TCM) and fixed tube current protocols. Methods: An experimental approach to evaluate organ doses in pediatric and adult anthropomorphic phantoms using thermoluminescent dosimeters (TLDs) was employed in this study. Several analyses were performed in order to establish the best way to achieve the main results in this investigation. The protocols used in this study were selected after an analysis of patient data collected from the Institute of Radiology of the School of Medicine of the University of São Paulo (InRad). The image quality was evaluated by a radiologist from this institution. Six chest adult protocols and four chest pediatric protocols were evaluated. Lung doses were evaluated for the adult phantom and lung and thyroid doses were evaluated for the pediatric phantom. The irradiations were performed using both a GE and a Philips CT scanner. Finally, organ doses measured with dosimeters were compared with Monte Carlo simulations performed with NCICT. Results: After analyzing the data collected from all CT examinations performed during a period of 3 yr, the authors identified that adult and pediatric chest CT are among the most applied protocol in patients in that clinical institution, demonstrating the relevance on evaluating organ doses due to these examinations. With regards to the scan parameters adopted, the authors identified that using 80 kV instead of 120 kV for a pediatric chest routine CT, with TCM in both situations, can lead up to a 28.7% decrease on the absorbed dose. Moreover, in comparison to the standard adult protocol, which is performed with fixed mAs, TCM, and ultra low-dose protocols resulted in dose reductions of up to 35.0% and 90.0%, respectively. Finally, the percent differences found between experimental and Monte Carlo simulated organ doses were within a 20% interval. Conclusions: The results obtained in this study measured the impact on the absorbed dose in routine chest CT by changing several scan parameters while the image quality could be potentially preserved.
AB - Purpose: To evaluate organ doses in routine and low-dose chest computed tomography (CT) protocols using an experimental methodology. To compare experimental results with results obtained by the National Cancer Institute dosimetry system for CT (NCICT) organ dose calculator. To address the differences on organ dose measurements using tube current modulation (TCM) and fixed tube current protocols. Methods: An experimental approach to evaluate organ doses in pediatric and adult anthropomorphic phantoms using thermoluminescent dosimeters (TLDs) was employed in this study. Several analyses were performed in order to establish the best way to achieve the main results in this investigation. The protocols used in this study were selected after an analysis of patient data collected from the Institute of Radiology of the School of Medicine of the University of São Paulo (InRad). The image quality was evaluated by a radiologist from this institution. Six chest adult protocols and four chest pediatric protocols were evaluated. Lung doses were evaluated for the adult phantom and lung and thyroid doses were evaluated for the pediatric phantom. The irradiations were performed using both a GE and a Philips CT scanner. Finally, organ doses measured with dosimeters were compared with Monte Carlo simulations performed with NCICT. Results: After analyzing the data collected from all CT examinations performed during a period of 3 yr, the authors identified that adult and pediatric chest CT are among the most applied protocol in patients in that clinical institution, demonstrating the relevance on evaluating organ doses due to these examinations. With regards to the scan parameters adopted, the authors identified that using 80 kV instead of 120 kV for a pediatric chest routine CT, with TCM in both situations, can lead up to a 28.7% decrease on the absorbed dose. Moreover, in comparison to the standard adult protocol, which is performed with fixed mAs, TCM, and ultra low-dose protocols resulted in dose reductions of up to 35.0% and 90.0%, respectively. Finally, the percent differences found between experimental and Monte Carlo simulated organ doses were within a 20% interval. Conclusions: The results obtained in this study measured the impact on the absorbed dose in routine chest CT by changing several scan parameters while the image quality could be potentially preserved.
KW - Monte Carlo simulations
KW - computed tomography
KW - dosimetry/exposure assessment
KW - image quality
KW - organ dose
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U2 - 10.1002/acm2.12505
DO - 10.1002/acm2.12505
M3 - Article
C2 - 30508315
AN - SCOPUS:85058047748
SN - 1526-9914
VL - 20
SP - 308
EP - 320
JO - Journal of applied clinical medical physics
JF - Journal of applied clinical medical physics
IS - 1
ER -