A fast Monte Carlo-based forward projector with complete physics modeling of Y-90 bremsstrahlung

Stephen C. Moore, Mi Ae Park, Morgan Cervo, Stefan P. Muller

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Scopus citations

Abstract

Intra-arterial administration of Y-90-microspheres is an established technique for radioembolization of hepatic tumors. We have previously developed a new approach for rapid simulation of bremsstrahlung from Y-90 beta particles; this method is being incorporated into the forward projector of a Monte Carlo (MC)-based SPECT reconstruction program. Conditional probability densities, derived from EGSnrc simulations, were first used to obtain multi-dimensional tables of equally likely parameters for bremsstrahlung production. Rapid simulation then consisted of randomly selecting a beta energy from a table of 100 equiprobable energies, a radial distance to the location of bremsstrahlung production for the given beta energy, and an equiprobable photon energy for the given beta energy and range. The rare nuclear de-excitation and internal pair-production processes yielding 1760- and 511-keV photons were also included. Simulated photons were used to build tables of distance- and energy-dependent resolution kernels (PSFs), including all collimator and detector interactions, and were also propagated through an attenuation map for 8 orders of scatter, yielding scatter-map (S-map) images in 40 energy bins from 59 to 859 keV. Primary and S-map photons were projected into 6 detector energy windows from 59 to 563 keV using convolution-forced detection (CFD) with the precomputed PSFs. Data were simulated and acquired from a 2.5-cm-diameter sphere of Y-90 centered within a water cylinder (7.2-cm diam. × 10.3 cm long). Energy spectra and projection images in the 6 windows were recorded with this phantom positioned ∼20 cm from the high-energy general-purpose collimators on a Siemens Symbia SPECT-CT scanner. Acquired and simulated spectra and images were in good agreement. The average absolute difference of counts between fully-MC-simulated and Smap+CFD-computed images was 13.6%; discrepancies can be further reduced by using wider CFD kernels for the highest energy windows.

Original languageEnglish (US)
Title of host publication2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012
Pages2699-2701
Number of pages3
DOIs
StatePublished - 2012
Externally publishedYes
Event2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012 - Anaheim, CA, United States
Duration: Oct 29 2012Nov 3 2012

Publication series

NameIEEE Nuclear Science Symposium Conference Record
ISSN (Print)1095-7863

Other

Other2012 IEEE Nuclear Science Symposium and Medical Imaging Conference Record, NSS/MIC 2012
CountryUnited States
CityAnaheim, CA
Period10/29/1211/3/12

ASJC Scopus subject areas

  • Radiation
  • Nuclear and High Energy Physics
  • Radiology Nuclear Medicine and imaging

Fingerprint Dive into the research topics of 'A fast Monte Carlo-based forward projector with complete physics modeling of Y-90 bremsstrahlung'. Together they form a unique fingerprint.

Cite this