New mesh-type phantoms and their dosimetric applications, including emergencies

Abstract

Committee 2 of the International Commission on Radiological Protection (ICRP) has constructed mesh-type adult reference computational phantoms by converting the voxel-type ICRP Publication 110 adult reference computational phantoms to a high-quality mesh format, and adding those tissues that were below the image resolution of the voxel phantoms and therefore not included in the Publication 110 phantoms. The new mesh phantoms include all the necessary source and target tissues for effective dose calculations, including the 8-40-µm-thick target layers of the alimentary and respiratory tract organs, thereby obviating the need for supplemental organ-specific stylised models (e.g. respiratory airways, alimentary tract organ walls and stem cell layers, lens of the eye, and skin basal layer). To see the impact of the new mesh-type reference phantoms, dose coefficients for some selected external and internal exposures were calculated and compared with the current reference values in ICRP Publications 116 and 133, which were calculated by employing the Publication 110 phantoms and the supplemental stylised models. The new mesh phantoms were also used to calculate dose coefficients for industrial radiography sources near the body, which can be used to estimate the organ doses of the worker who is accidentally exposed by an industrial radiography source; in these calculations, the mesh phantoms were deformed to reflect the size of the worker, and also to evaluate the effect of posture on dose coefficients.

Optimizing Coded Aperture Imaging techniques to allow for online tracking of fiducial markers with high‐energy scattered radiation from treatment beam

“…Specifically, the unstructured mesh phantoms that are currently being tested and verified through ICRP Task Group 103 for use in Monte Carlo simulations could allow for patient-specific, pretreatment validation of CAI methods. 43,44 Improvements to the MCNP6 model are ongoing to decrease required computation time, as our simulations took between 3 and 15 days (depending on the complexity of the geometry). By changing the geometry definitions in the MCNP framework from mathematical definitions of every surface and cell of the individual elements, to an embedded repeating lattice structure, computation times can be decreased by several percent to several orders of magnitude for the more complex apertures.…”

Development of Detailed Korean Adult Eye Model for Lens Dose Calculation

“…Since 2016, a project by ICRP Task Group 103 has been underway to convert the ICRP voxel-type reference phantoms into a high-quality/fidelity mesh format to address the limitations due to the nature of voxel structure (i.e., stair-stepped surface and holes in wall organs/tissues) [6]. Recently, the ICRP mesh-type reference computational phantoms (MRCPs) for adult male and female were completed, which include all organs and tissues, even including very thin radiosensitive layers, required for effective dose calculations, while maintaining the topology of the ICRP-110 phantoms.…”

OpenDose: Open-Access Resource for Nuclear Medicine Dosimetry

“…where ← , 7 is a logical evolution that accounts for the increasing availability of refined description of human geometry. In addition, recent developments propose polygonal mesh models (7), that can overcome voxel-based model limitations in the description of thin structures like organ walls.…”