Creation and use of adjustable 3D phantoms: Application for the lung monitoring of female workers
Résumé
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. © 2010 Health Physics Society.
Mots clés
article
audiovisual equipment
body burden
breast
calibration
computer program
factual database
female
histology
human
image quality
lung
Monte Carlo method
occupational exposure
organ size
radiation dose
radiation exposure
radiation protection
supine position
thorax
Body Burden
Breast
Calibration
Databases
Factual
Female
Humans
Lung
Models
Anatomic
Monte Carlo Method
Occupational Exposure
Organ Size
Phantoms
Imaging
Radiation Dosage
Radiation Protection
Software
Supine Position
Thorax