Chin-Hui Wu

Pediatric patients are more sensitive to ionising radiation, making radiation protection a critical concern in dental cone-beam computed tomography (CBCT). This study aimed to assess organ and effective doses and associated radiation risk in pediatric imaging, to validate the PCXMC-20Rotation Monte Carlo code against optically stimulated luminescence dosimeters (OSLDs), and to evaluate dose-area product (DAP) as an indicator for effective dose ( E ) and risk of exposure-induced cancer death (REID). Age-specific 5 and 10 year-old head-and-neck phantoms were manufactured by three-dimensional (3D) printing and embedded with seventeen OSLDs each. The phantoms were scanned on a CS 9000 system in panoramic mode at both ages and in 3D maxillary and mandibular CBCT mode at 10 years. DAP was recorded with a VacuDAP metre and used in PCXMC-20Rotation to calculate organ doses, E , and REID. In panoramic mode, differences in E between PCXMC and OSLD were −4.7% (5 year) and −10.7% (10 year), and organ dose rankings were generally similar. PCXMC overestimated oral mucosa dose in 3D mandibular imaging, where total E was approximately 3–5 times higher than in panoramic mode. DAP correlated strongly with E ( R ² = 0.971–0.987) and with REID ( R ² = 0.967–0.986); the highest REID (8.1 × 10 ⁻⁶ ) was predicted for 10 year-old girls undergoing 3D mandibular CBCT. PCXMC estimated E within ±15% of OSLD measurements for both panoramic and 3D modes. DAP may serve as a practical indicator of E and REID in pediatric CBCT. From a radiation protection perspective, the findings support the use of child-specific exposure settings and DAP monitoring as approaches to minimise unnecessary radiation exposure, particularly in female pediatric patients.

This study discussed comparing result accuracy and time cost under different tally methods using MCNP6 for a novel transmission x-ray tube which was designed for the Auger electron yield with specific material (e.g. iodine). The assessment included photon spectrum, percent depth dose, mass-energy absorption coefficient corresponding to air and water, and figure of merit comparison. The mean energy of in-air phantom was from 41.8 keV (0 mm) to 40.9 keV (100 mm), and the mean energy of in-water phantom was from 41.41 keV (0 mm) to 45.2 keV (100 mm). The specific dose conversion factors based mass-energy absorption coefficient corresponding to different materials was established and the difference was less than 2% for the dose conversion of FMESH comparing to measurement data. FMESH had better figure of merit (FOM) than the F6 tally for the dose parameter assessment, which mean the dose calculation that focused on the superficial region could be assessed with more calculation efficiency by FMESH tally for this novel transmission x-ray tube. The results of this study could help develop treatment planning system (TPS) to quickly obtain the calculated data for phase space data establishment and heterogeneous correction under different physical condition settings.

(1) Background: The purpose of this study was to evaluate the radiation awareness level of the public in Taiwan. (2) Methods: This study designed an online survey form to investigate the radiation awareness level with six topics: basic knowledge of radiation, environmental radiation, medical radiation, radiation protection, and university/corporate social responsibility. The score of respondents were converted into knowledge and responsibility indexes for the quantitative evaluation. Logistic regression was used to assess the correlation between the knowledge index and individual factors. Paired t-test was used to assess the significant difference in knowledge index between pre-training and post-training. (3) Results: The knowledge index of each job category reflected the proportion of radiation awareness of the job. The logistic regression result indicated that radiation-related people could get higher knowledge index. The paired t-test indicated that the knowledge index before and after class had significant differences in all question topics. (4) Conclusions: The public’s awareness of medical radiation was the topic that needed to be strengthened the most—the responses with high knowledge index significantly correlated with their experience in radiation education training or radiation-related jobs. It significantly increased the knowledge index of radiation if the public received radiation education training.