Monte Carlo simulations of absorbed dose in a mouse phantom from 18‐fluorine compounds

Abstract

The purpose of this study was to calculate internal absorbed dose distribution in mice from pre-clinical small animal PET imaging procedures with fluorine-18 labeled compounds (18FDG, 18FLT, and fluoride ion). The GATE Monte Carlo software and a realistic, voxel-based mouse phantom that included a subcutaneous tumor were used to perform simulations. Discretized time-activity curves obtained from dynamic in vivo studies with each of the compounds were used to set the activity concentration in the simulations. For 18FDG, a realistic range of uptake ratios was considered for the heart and tumor. For each simulated time frame, the biodistribution of the radionuclide in the phantom was considered constant, and a sufficient number of decays were simulated to achieve low statistical uncertainty. Absorbed dose, which was scaled to take into account radioactive decay, integration with time, and changes in biological distribution was reported in mGy per MBq of administered activity for several organs and uptake scenarios. The mean absorbed dose ranged from a few mGy/MBq to hundreds of mGy/MBq. Major organs receive an absorbed dose in a range for which biological effects have been reported. The effects on a given investigation are hard to predict; however, investigators should be aware of potential perturbations especially when the studied organ receives high absorbed dose and when longitudinal imaging protocols are considered.

Radiation Biology Irradiator Dose Verification Survey

“…Most of the advancements in computational phantom technology first focused on anthropomorphic phantoms. Small animal computational model development has since followed the same trajectory with equation based models (9, 10) and more recently advanced voxel based models (11)(12)(13)(14)(15).…”

Development of a mouse computational model for MCNPx based on Digimouse (r) images and dosimetric assays

“…This has allowed the modeling of internal organs motion due to heartbeat and breathing. The model was applied later in several mice dosimetry studies (Bretin et al, 2013;Taschereau, Chatziioannou, 2007;Larsson et al, 2007;Boutaleb et al, 2009;Keenan et al, 2010;Larsson et al, 2011;Mauxion et al, 2013;Xie, Zaidi, 2013;Lin et al, 2014). Situ, Hoffman, Hartmann (2005) and Stabin et al (2006) published voxel phantoms of mice with segmentation process based on MicroCT images.…”

A Prototype PET Scanner with DOI-Encoding Detectors

“…High sensitivity is needed to increase signal-to-noise ratio of the images to reliably detect lower levels of radiotracer uptake and to reduce the injected dose (reducing radiation dose to the subject) (13) and scan time (increasing temporal resolution for dynamic studies). High spatial resolution is required to detect small structures and lesions and to improve quantification by reducing the partialvolume effect.…”