Hybrid computational phantoms for medical dose reconstruction

Abstract

As outlined in NCRP Report No. 160, the average value of the effective dose to exposed individual in the United States has increased by a factor of 1.7 over the time period 1982 to 2006, with the contribution of medical exposures correspondingly increasing by a factor of 5.7. at present, medical contributors to the effective dose include computed tomography (50% of total medical exposure), nuclear medicine (25%), interventional fluoroscopy (15%), and conventional radiography and diagnostic fluoroscopy (10%). This increased awareness of medical exposures has led to a graduate shift in the focus of radiation epidemiological studies from traditional occupational and environmental exposures to those focusing on cohorts of medical patients exposed to both diagnostic and therapeutic sources. The assignment of organ doses to patients in either a retrospective or prospective study has increasingly relied on the use of computational anatomical phantoms. In this paper, we review the various methods and approaches used to construction patient phantom models to include anthropometric databases, cadaver imaging, prospective volunteer imaging studies, and retrospective image reviews. Phantom format typesstylized, voxel, and hybrid -as well as phantom morphometric categories -reference, patientdependent, and patient-specific -are next defined and discussed. Specific emphasis is given to hybrid phantoms -those defined through the use of combinations of polygon mesh and NURBS surfaces. The concept of a patient-dependent phantom is reviewed in which phantoms of non-50 th percentile heights and weights are designed from population-based morphometric databases and provided as a larger library of phantoms for patient matching and lookup of refined values of organ dose coefficients and/or radionuclide S values. We close with two brief examples of the use of hybrid phantoms in medical dose reconstruction -diagnostic nuclear medicine for pediatric subjects and interventional fluoroscopy for adult patients.

Dosimetric characterization and organ dose assessment in digital breast tomosynthesis: Measurements and Monte Carlo simulations using voxel phantoms

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Modeling the adult female phantom in the supine and prone postures and initial dose assessment in breast cancer diagnosis with Neutron Stimulated Emission Computed Tomography

“…This process was performed using Rhinoceros TM (McNeel North America, WA). Then, organs were voxelized using an innovative method developed by our research group and a hybrid voxel phantom was created (Bolch et al, 2010) using the Rhinoceros software (Hoseinian et al, 2014).…”

Late health effects of ionizing radiation: bridging the experimental and epidemiological divide

“…Another area where progress in dosimetry can improve epidemiological studies is computational phantoms. Bolch et al (2010) review emerging techniques for constructing patientspeciWc phantoms, which are expected to become the basis of a new generation of dose reconstruction methods.…”