Organs’ absorbed dose and comparison of different methods for effective dose calculation in computed tomography of parathyroid glands

Abstract

Objective. To estimate organs’ absorbed dose from the two-phase CT of parathyroid glands, effective dose (ED) based on three different methods, and compare the dose values with those reported by other published protocols. Methods. Volumetric-computed-tomography-dose-index (CTDIvol), dose-length-product (DLP), and the corresponding scan length during each phase of a parathyroid protocol were recorded, for seventy-six patients. One k-factor, and two different k-factors for the neck and chest area were used to estimate the ED from DLP. A Monte Carlo software, VirtualDoseCT, was also used for the estimation of organs’ absorbed dose and ED. Results. Two-phase parathyroid CT resulted in a mean ED of 3.93 mSv, 4.29 mSv and 4.21 mSv according to the one k-factor, two k-factors, and VirtualDoseCT methods, respectively. The two k-factors method resulted in a slight overestimation of 1.9% in total ED compared to VirtualDoseCT. No statistically significant difference was found in ED values between these methods (Wilcoxon test, p > 0.05), except for female patients in the pre-contrast phase. The organs inside the scanning field of view (SFOV) received the following doses: thymus 23.3 mGy, lungs 11.5 mGy, oesophagus 9.2 mGy, thyroid 6.9 mGy, and breast 6.3 mGy. The ED and organs’ dose (OD) values were significantly lower in the pre-contrast than in the arterial phase (Wilcoxon test, p < 0.001). A statistically significant difference was observed between male and female patients for the pre-contrast phase (Mann-Whitney test, p < 0.05), regarding the ED values obtained with the two k-factors method and VirtualDoseCT software. Conclusions. The two k-factors method could be applied for the ED estimation in clinical practice, if appropriate software is not available. An extensive range of ED values derived from the literature, mainly depending on the acquisition protocol parameters and the estimation method.

Introducing fitting models for estimating age‐specific dose and effective dose in paediatric patients undergoing head, chest and abdomen–pelvis imaging protocols: a patient study

“…Radiation deterministic effects occur following receive of relatively high radiation doses, and these effects have been encountered in interventional radiology and in CT studies 4 . This trend is mirrored in other developed and developing countries as well 5 …”

“…4 This trend is mirrored in other developed and developing countries as well. 5 The concerns about increased radiation risk hold greater significance in children due to their heightened radiosensitivity 6 and extended lifetimes, which could potentially magnify long-term radiation effects. 7 In such cases, the precise quantification of patient dose becomes a critical task to assess radiation risks stemming from the escalating number of CT scans, particularly among paediatric patients.…”