Creation and Use of Adjustable 3d Phantoms: Application for the Lung Monitoring of Female Workers

Abstract

In vivo counting measurements, used for the monitoring of workers with internal contamination risks, are based on the use of calibration physical phantoms. However, such phantoms do not exist for female subjects. Computational calibration using numerical representations, Mesh and non-uniform rational basis spline (NURBS) geometries, was thus considered. The study presented here is focused on the creation of different female thoracic phantoms with various breast sizes and chest girths. These 3D models are used to estimate the radiation attenuation with morphology and the resulting variation of the calibration coefficient of a typical 4-germanium in vivo counting system. A basic Mesh female thoracic phantom was created from the International Commission on Radiological Protection Adult Female Reference Computational Phantom. Using this basic phantom, different chest girths (85, 90, 100, 110, and 120) and cup sizes (A to F) were created representing the most common thoracic female morphologies, as recommended by the available and relevant literature. Variation of breast tissue composition and internal organ volumes with morphology were also considered. As a result, 34 thoracic female phantoms were created combining different cup sizes and chest girths. For the 85 chest girth, at very low energies (15 keV), a relative counting efficiency variation of about 85% was observed between the A and E cups. As a result of this study, breast size dependent calibration coefficients, between 15 keV and 1.4 MeV, were obtained and tabulated for a typical lung counting germanium system.

Personalised Body Counter Calibration Using Anthropometric Parameters

“…Features related to body height and other lengths or other body parts show low performances. No correlation ( 2 < 0.05 for XCAT for all photon energies) was observed between cup size (difference of bust circumference and underbust circumference) and counting efficiency for lungs, which was reported by Hegenbart et al (2008) and Farah, Broggio and Franck (2010). However, larger detectors (phoswich detectors and a 2 × 2 HPGe array) and detector positions (frontal to the breasts in the first case) were chosen in these works, which could explain the deviations.…”

“…The case base is a set of problems with an associated solution generated by experts. EquiVox uses 24 adult female computational phantoms with varying cup size and chest girth based on ICRP-AF and NURBS modelling (Farah, Broggio and Franck 2010 …”

“…This topic was addressed by several authors. Hegenbart et al (2008) and Farah, Broggio and Franck (2010) created series of person-dependent female phantoms with varying cup sizes for application to lung counting with phoswich and germanium detectors respectively. They found a negative correlation of breast mass and cup size to counting efficiency.…”

Nouvelle méthode de surveillance des travailleuses du nucléaire par anthroporadiamétrie : utilisation des calculs Monte Carlo associés aux fantômes déformables de type Mesh et NURBS

“…Ce paragraphe résume les méthodes utilisées, le détail de création de la librairie peut être trouvé dans Farah et al (2010a).…”

Development of a 3D human body library based on polygonal mesh surface for whole body counter set-up calibration

“…And the non-uniform rational basis spline (NURBS) geometry offers a common mathematical framework for implicit and parametric polynomial forms. This mathematical modelling tool is frequently used in computer graphics and animated films industry, thereby showing a method how to overcome some limitations related to the computational voxel phantoms [1][2][3][4]. Although the computational voxel phantoms are anatomically realistic models, most of them are made in supine position and due to the geometry modelling technique the resize of the voxel grids are the only operations allowed which introduces problems of smoothness and continuity when it is necessary to have these models in sitting position.…”