Author: John P. Aris, Wesley E. Bolch, Natalia Estefania Carrasco-Rojas, Ann M. Chan, Chansoo Choi, Aitor Gallastegui Menoyo, Rowan James Milner, Bangho Shin, Maria M. Von Chamier 👨🔬
Affiliation: University of Florida 🌍
Purpose: In preclinical studies, minipigs serve as valuable experimental models for predicting absorbed doses due to their anatomical and physiological similarities to humans. However, minipig computational phantoms have not yet been developed for dose estimates. In the present study, a pair of male and female micro-Yucatan minipig phantoms were developed for use in estimating the absorbed doses for internal medical exposures (e.g., radiopharmaceutical therapies).
Methods: To construct the phantoms, we first acquired computed tomography (CT) and magnetic resonance (MR) images of a pair of 6-month-old micro-Yucatan minipigs: a castrated male weighing 19.2 kg with a nose-to-hip length of 90 cm and a female weighing 18.8 kg with a nose-to-hip length of 88 cm. Individual organs and tissues were then segmented by manually contouring them on the acquired CT and MR slices using ImageJ, an open-source image processing software developed by the National Institutes of Health (NIH).
Results: In the present study, we developed a pair of male and female micro-Yucatan minipigs in a voxel format. Each phantom comprises approximately 2.9 billion voxels. With high voxel resolution (i.e., 0.904 X 0.904 X 0.8 mm3 for the male and 0.729 X 0.729 X 0.8 mm3 for the female), we confirmed that the developed phantoms precisely define the majority of the internal organs required for the calculation of effective dose.
Conclusion: The minipig phantoms developed in the present study are at this point the first and only computational phantoms that precisely represent the minipig anatomy. We believe that the developed phantoms can be beneficially used to compute absorbed doses in various internal medical exposures. In future studies, we will convert the voxel-based minipig phantoms into mesh format, which is considered the most advanced phantom geometry.