Search

Evaluating the radiation dose of target organs of a laboratory mouse requires a glass dosimeter to be surgically inserted at the irradiated location. However, precisely inserting the glass dosimeter at the same location in different mice is rarely achieved, reducing the reliability of the measured radiation dose. To address this limitation, 3-D mouse phantom was developed using computed tomography scanning and 3-D printing technology. The radiation dose of target organs was assessed using four mouse models: laboratory mouse, 3-D mouse phantom, Monte Carlo N-Particle (MCNP) 3-D phantom, and MCNP simulation. In all the experiments, the brain, heart, lungs, and abdomen were irradiated with 100 mGy of measured air kerma at a 6 mGyh–1 air kerma rate. A small volume glass dosimeter was inserted into the mouse models to assess the radiation dose, and the reliability of the glass dosimeter reading system was evaluated using the dose-response curves. The dose values of the laboratory mouse and 3-D-printed mouse phantom were found to differ by up to 3.3 %. This study provides a method to accurately measure the radiation dose to target organs, enhancing the reliability of pre-experiments.

To analyze the biological effects of radiation, it is important that the conditions of in vitro experiments match closely with those of in vivo experiments. In this study, we constructed an irradiation system to conduct irradiation experiments under conditions similar to those of in vivo experiments. The Dongnam Institute of Radiological and Medial Sciences has a gamma irradiator including 60Co radioisotope for research purposes and accreditation for standard calibration of the ion chamber. The temperature of the water phantom was maintained the same as that of the normal human body, and the physical dosimetry was carried out accurately using the ion chamber with traceability. We report the measurement of lateral profiles, depth profiles, and absorbed dose rate in water, Dw, at the irradiation location of the blood samples using a farmer-type ion chamber. We simulated the source, collimator, irradiator, phantom, and extra structure of the gamma irradiation system using the Monte Carlo code and compared the simulated and the experimental results. The experimentally and theoretically evaluated dose rates were 0.2975 ± 0.0055 Gymin–1 (at coverage factor k = 2) and 0.2978 ± 0.0052 Gymin–1 (at coverage factor k = 2) at source-to-surface distance of 100 cm and 5 gcm–2 depth in the water phantom, respectively. Blood irradiation will be conducted in vitro, under conditions similar to in vivo conditions, to provide the dose-response curve based on dosimetry with traceability.

In this study, a method of directly evaluating the dose received by the highly radiation-sensitive mammary gland during mammography was investigated, and a corresponding breast phantom was produced that expresses a mammary gland, as an alternative to the existing mixed-form phantom. After designing this breast phantom by performing Monte Carlo simulations, the glandular dose was evaluated and compared with that of a mixed-form phantom. Then, dose evaluation was conducted for current commercial filament materials that could be used to fabricate the phantom by 3-D printing. The results showed that the dose received by the mammary gland was in the range of 1.089-1.237 mGy, and the average difference from that determined using the mixed-form phantom was approximately 1.2 %. Among the filament materials, polylactic acid showed the dose that was the most similar to that of the mammary gland tissue, differing by approximately 2.4 %. Overall, the research results suggest that it is meaningful to evaluate the glandular dose using the developed phantom instead of a mixed-form phantom. Besides, polylactic acid is the most appropriate material for fabricating the mammary gland tissue using a 3-D printer.