A comparison of pediatric and adult CT organ dose estimation methods
نویسندگان
چکیده
BACKGROUND Computed Tomography (CT) contributes up to 50% of the medical exposure to the United States population. Children are considered to be at higher risk of developing radiation-induced tumors due to the young age of exposure and increased tissue radiosensitivity. Organ dose estimation is essential for pediatric and adult patient cancer risk assessment. The objective of this study is to validate the VirtualDose software in comparison to currently available software and methods for pediatric and adult CT organ dose estimation. METHODS Five age groups of pediatric patients and adult patients were simulated by three organ dose estimators. Head, chest, abdomen-pelvis, and chest-abdomen-pelvis CT scans were simulated, and doses to organs both inside and outside the scan range were compared. For adults, VirtualDose was compared against ImPACT and CT-Expo. For pediatric patients, VirtualDose was compared to CT-Expo and compared to size-based methods from literature. Pediatric to adult effective dose ratios were also calculated with VirtualDose, and were compared with the ranges of effective dose ratios provided in ImPACT. RESULTS In-field organs see less than 60% difference in dose between dose estimators. For organs outside scan range or distributed organs, a five times' difference can occur. VirtualDose agrees with the size-based methods within 20% difference for the organs investigated. Between VirtualDose and ImPACT, the pediatric to adult ratios for effective dose are compared, and less than 21% difference is observed for chest scan while more than 40% difference is observed for head-neck scan and abdomen-pelvis scan. For pediatric patients, 2 cm scan range change can lead to a five times dose difference in partially scanned organs. CONCLUSIONS VirtualDose is validated against CT-Expo and ImPACT with relatively small discrepancies in dose for organs inside scan range, while large discrepancies in dose are observed for organs outside scan range. Patient-specific organ dose estimation is possible using the size-based methods, and VirtualDose agrees with size-based method for the organs investigated. Careful range selection for CT protocols is necessary for organ dose optimization for pediatric and adult patients.
منابع مشابه
Thorax organ dose estimation in computed tomography based on patient CT data using Monte Carlo simulation
Background: This study presents patient specific and organ dose estimation in computed tomography (CT) imaging of thorax directly from patient CT image using Monte Carlo simulation. Patient's CT image is considered as the patient specific phantom and the best representative of patient physical index in order to calculate specific organ dose. Materials and Methods: EGSnrc /BEAMnr...
متن کاملOrgan Dose Measurement in Computed Tomography Using Thermoluminescence Dosimeter in Locally Developed Phantoms
Introduction: Organ dose estimation using thermoluminescence dosimeter (TLD) is known to be a standard, although many other methods, such as simulation software, optically stimulated luminescent dosimeters, and photodiodes are still in use. This study aimed at directly measuring mean organ doses to the selected organs in the head/neck, chest, and abdominal regions from four computed tomography ...
متن کاملMeasurement of organ dose in abdomen-pelvis CT exam as a function of mA, KV and scanner type by Monte Carlo method .
Background: CT is a diagnostic imaging modality giving higher patient dose in comparison with other radiological procedures, so the calculation of organ dose in CT exams is very important. While methods to calculate the effective dose have been established (ICRP 26 and ICRP 60), they depend heavily on the ability to estimate the dose to radiosensitive organs from the CT procedure. However, dete...
متن کاملThe comparison of serial SPECT-CT imaging to estimate absorbed dose to the organ at risk from peptide receptor radionuclide therapy dosimetry
Introduction: In Peptide Receptor Radionuclide Therapy (PRRT), the administration of radionuclide such as Lu-177 label with a pharmaceutical agent useful to destroy the lesion. The amount of Lu-177 radioactivity administered to the patients is still not standardize and generally not more than 7.4 GBq per session due to the patient’s safety issues. The first cycle of Lu-177 is a...
متن کاملMeasurement of organ dose in chest CT examination using Monte Carlo simulation
Background: Exposure conditions in CT examinations are quite different from conventional Xray. In CT examination higher dose is given to patient in comparison with the dose in other diagnostic examinations. In order to calculate organ effective dose in chest CT, Monte Carlo simulation has been used in this study. Materials and Methods: The Impact survey data were used to determine the ...
متن کامل