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3D absorbed dose calculations based on SPECT: Evaluation for 111-In/90-Y therapy using Monte Carlo simulations.

Author:
  • Michael Ljungberg
  • E Frey
  • Katarina Sjögreen Gleisner
  • XW Liu
  • Y Dewaraja
  • Sven-Erik Strand
Publishing year: 2003
Language: English
Pages: 99-107
Publication/Series: Cancer Biotherapy & Radiopharmaceuticals
Volume: 18
Issue: 1
Document type: Journal article
Publisher: Mary Ann Liebert, Inc.

Abstract english

A general method is presented for patient-specific three-dimensional (3D) absorbed dose calculations based on quantitative SPECT activity measurements. The computational scheme includes a method for registration of the CT study to the SPECT image, and compensation for attenuation, scatter, and collimator-detector response including septal penetration, performed as part of an iterative reconstruction method. From SPECT images, the absorbed dose rate is calculated using an EGS4 Monte Carlo code, which converts the activity distribution to an absorbed dose rate distribution. Evaluation of the accuracy in the activity quantification and the absorbed dose calculation is based on realistic Monte Carlo simulated SPECT data of a voxel-computer phantom and In-111 and Y-90. Septal penetration was not included in this study. The SPECT-based activity concentrations and absorbed dose distributions are compared to the actual values; the results imply that the corrections for attenuation and scatter yield results of high accuracy. The presented method includes compensation for most parameters deteriorating the quantitative image information. Inaccuracies are, however, introduced by the limited spatial resolution of the SPECT system, which are not fully compensated by the collimator-response correction. The proposed evaluation methodology may be used as a basis for future inter-comparison of different dosimetry calculation schemes.

Keywords

  • Cancer and Oncology
  • simulation
  • attenuation
  • scatter
  • quantification
  • SPECT
  • Monte Carlo
  • dosimetry

Other

Published
  • ISSN: 1557-8852
Sven-Erik Strand
E-mail: sven-erik.strand [at] med.lu.se

Project manager

Systemic Radiation Therapy Group

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Professor emeritus

Medical Radiation Physics, Lund

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