A methodology to develop computational phantoms with adjustable posture for WBC calibration

Abstract

A Whole Body Counter (WBC) is a facility to routinely assess the internal contamination of exposed workers, especially in the case of radiation release accidents. The calibration of the counting device is usually done by using anthropomorphic physical phantoms representing the human body. Due to such a challenge of constructing representative physical phantoms a virtual calibration has been introduced. The use of computational phantoms and the Monte Carlo method to simulate radiation transport have been demonstrated to be a worthy alternative. In this study we introduce a methodology developed for the creation of realistic computational voxel phantoms with adjustable posture for WBC calibration. The methodology makes use of different software packages to enable the creation and modification of computational voxel phantoms. This allows voxel phantoms to be developed on demand for the calibration of different WBC configurations. This in turn helps to study the major source of uncertainty associated with the in vivo measurement routine which is the difference between the calibration phantoms and the real persons being counted. The use of realistic computational phantoms also helps the optimization of the counting measurement. Open source codes such as MakeHuman and Blender software packages have been used for the creation and modelling of 3D humanoid characters based on polygonal mesh surfaces. Also, a home-made software was developed whose goal is to convert the binary 3D voxel grid into a MCNPX input file. This paper summarizes the development of a library of phantoms of the human body that uses two basic phantoms called MaMP and FeMP (Male and Female Mesh Phantoms) to create a set of male and female phantoms that vary both in height and in weight. Two sets of MaMP and FeMP phantoms were developed and used for efficiency calibration of two different WBC set-ups: the Doel NPP WBC laboratory and AGM laboratory of SCK-CEN in Mol, Belgium.

Calibration of the LDI/CDTN Whole Body Counter us-ing two physical phantoms

“…i.e., counting efficiencies vary according to size, weight, tissue thickness and overall dimensions of the individual to be monitored [3,4]. The calibration performed with the PET-BOMAB #1…”

“…A variety of setups may be applied in order to obtain a better counting efficiency of the whole system [3,4]. The accuracy of the measurement relies on the quality of the calibration in regard to the distribution of the radionuclide in the whole body or in various organs and tissues compared to the individual biotype.…”

Virtual clinical trials in medical imaging: a review

“…Various methods have been developed to position computational phantoms. [81][82][83] In addition to positioning, certain breast imaging modalities, such as mammography and tomosynthesis, also require the patient to undergo varying degrees of breast compression. This type of deformation is typically simulated within a computational phantom using finite-element methods.…”

Advances in Computational Human Phantoms and Their Applications in Biomedical Engineering—A Topical Review

“…Similar techniques were used to create a library of pediatric models based on reference models from the Virtual Population [11] [12]. Interactive tools to change the posture of anatomical models permit positioning of bones around articulated joints in real-time and interpolate the tissue deformation using techniques such as dual quaternion skinning [13] [14] [15].…”