Dose coefficients of percentile-specific computational phantoms for photon external exposures

Practical implementation of the International Commission on Radiological Protection's (ICRP) system of protection requires the availability of appropriate methods and data. The work of Committee 2 is concerned with the development of reference data and methods for the assessment of internal and external radiation exposure of workers and members of the public. This involves the development of reference biokinetic and dosimetric models, reference anatomical models of the human body, and reference anatomical and physiological data. Following ICRP's 2007 Recommendations, Committee 2 has focused on the provision of new reference dose coefficients for external and internal exposure. As well as specifying changes to the radiation and tissue weighting factors used in the calculation of protection quantities, the 2007 Recommendations introduced the use of reference anatomical phantoms based on medical imaging data, requiring explicit sex averaging of male and female organ-equivalent doses in the calculation of effective dose. In preparation for the calculation of new dose coefficients, Committee 2 and its task groups have provided updated nuclear decay data (ICRP Publication 107) and adult reference computational phantoms (ICRP Publication 110). New dose coefficients for external exposures of workers are complete (ICRP Publication 116), and work is in progress on a series of reports on internal dose coefficients to workers from inhaled and ingested radionuclides. Reference phantoms for children will also be provided and used in the calculation of dose coefficients for public exposures. Committee 2 also has task groups on exposures to radiation in space and on the use of effective dose.

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

Annals of the ICRP ◽

10.1177/0146645318756231 ◽

2018 ◽

Vol 47 (3-4) ◽

pp. 45-62 ◽

Cited By ~ 21

Author(s):

C.H. Kim ◽

Y.S. Yeom ◽

T.T. Nguyen ◽

M.C. Han ◽

C. Choi ◽

...

Keyword(s):

Basal Layer ◽

Thick Target ◽

Image Resolution ◽

The Body ◽

Radiological Protection ◽

Organ Doses ◽

Industrial Radiography ◽

Dose Coefficients ◽

The Impact ◽

Computational Phantoms

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.

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Computational phantoms, ICRP/ICRU, and further developments

Annals of the ICRP ◽

10.1177/0146645318756229 ◽

2018 ◽

Vol 47 (3-4) ◽

pp. 35-44 ◽

Cited By ~ 3

Author(s):

M. Zankl ◽

J. Becker ◽

C. Lee ◽

W.E. Bolch ◽

Y.S. Yeom ◽

...

Keyword(s):

Three Dimensional ◽

Organ Dose ◽

Thick Target ◽

Boundary Representation ◽

Radiological Protection ◽

Mathematical Expressions ◽

Dose Coefficients ◽

Computational Phantoms ◽

Voxel Phantoms ◽

Icrp Publication

Phantoms simulating the human body play a central role in radiation dosimetry. The first computational body phantoms were based upon mathematical expressions describing idealised body organs. With the advent of more powerful computers in the 1980s, voxel phantoms have been developed. Being based on three-dimensional images of individuals, they offer a more realistic anatomy. Hence, the International Commission on Radiological Protection (ICRP) decided to construct voxel phantoms representative of the adult Reference Male and Reference Female for the update of organ dose coefficients. Further work on phantom development has focused on phantoms that combine the realism of patient-based voxel phantoms with the flexibility of mathematical phantoms, so-called ‘boundary representation’ (BREP) phantoms. This phantom type has been chosen for the ICRP family of paediatric reference phantoms. Due to the limited voxel resolution of the adult reference computational phantoms, smaller tissues, such as the lens of the eye, skin, and micron-thick target tissues in the respiratory and alimentary tract regions, could not be segmented properly. In this context, ICRP Committee 2 initiated a research project with the goal of producing replicas of the ICRP Publication 110 phantoms in polygon mesh format, including all source and target regions, even those with micron resolution. BREP phantoms of the fetus and the pregnant female at various stages of gestation complete the phantoms available for radiation protection computations.

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