Advanced

A dosimetry model for the small intestine incorporating intestinal wall activity and cross-doses.

Jönsson, Lena M LU ; Liu, Xiaowei; Jönsson, Bo-Anders LU ; Ljungberg, Michael LU and Strand, Sven-Erik LU (2002) In Journal of Nuclear Medicine 43(12). p.1657-1664
Abstract
Current internal radiation dosimetry models for the small intestine, and for most walled organs, lack the ability to account for the activity uptake in the intestinal wall. In existing models the cross-dose from nearby loops of the small intestine is not taken into consideration. The aim of this investigation was to develop a general model for calculating the absorbed dose to the radiation-sensitive cells in the small intestinal mucosa from radionuclides located in the small intestinal wall or contents. Methods: A model was developed for calculation of the self-dose and cross-dose from activity in the intestinal wall or contents. The small intestine was modeled as a cylinder with 2 different wall thicknesses and with an infinite length.... (More)
Current internal radiation dosimetry models for the small intestine, and for most walled organs, lack the ability to account for the activity uptake in the intestinal wall. In existing models the cross-dose from nearby loops of the small intestine is not taken into consideration. The aim of this investigation was to develop a general model for calculating the absorbed dose to the radiation-sensitive cells in the small intestinal mucosa from radionuclides located in the small intestinal wall or contents. Methods: A model was developed for calculation of the self-dose and cross-dose from activity in the intestinal wall or contents. The small intestine was modeled as a cylinder with 2 different wall thicknesses and with an infinite length. Calculations were performed for various mucus thicknesses. S values were calculated using the EGS4 Monte Carlo simulation package with the PRESTA algorithm and the simulation results were integrated over the depth of the radiosensitive cells. The cross-organ dose was calculated by summing the dose contributions from other intestinal segments. Calculations of S values for self-dose and cross-dose were made for monoenergetic electrons, 0.050–10 MeV, and for the radionuclides 99mTc, 111In, 131I, 67Ga, 90Y, and 211At. Results: The self-dose S value from activity located in the small intestinal wall is considerably greater than the S values for self-dose from the contents and the cross-dose from wall and contents except for high electron energies. For all radionuclides investigated and for electrons 0.10–0.20 MeV and 8–10 MeV in energy, the cross-dose from activity in the contents is higher than the self-dose from the contents. The mucus thickness affects the S value when the activity is located in the contents. Conclusion: A dosimetric model for the small intestine was developed that takes into consideration the localization of the radiopharmaceutical in the intestinal wall or in the contents. It also calculates the contribution from self-dose and cross-dose. With this model, more accurate calculations of absorbed dose to radiation-sensitive cells in the intestine are possible. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
intestine, EGS4, radiation dosimetry, Monte Carlo simulations, cross-dose
in
Journal of Nuclear Medicine
volume
43
issue
12
pages
1657 - 1664
publisher
Society of Nuclear Medicine
external identifiers
  • wos:000179670100018
  • scopus:0036897571
ISSN
0161-5505
language
English
LU publication?
yes
id
f9942a1f-76b0-45d8-b947-b441f019b585 (old id 111573)
alternative location
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=12468516&dopt=Abstract
http://jnm.snmjournals.org/cgi/content/abstract/43/12/1657
date added to LUP
2007-07-19 16:29:43
date last changed
2017-01-01 06:45:16
@article{f9942a1f-76b0-45d8-b947-b441f019b585,
  abstract     = {Current internal radiation dosimetry models for the small intestine, and for most walled organs, lack the ability to account for the activity uptake in the intestinal wall. In existing models the cross-dose from nearby loops of the small intestine is not taken into consideration. The aim of this investigation was to develop a general model for calculating the absorbed dose to the radiation-sensitive cells in the small intestinal mucosa from radionuclides located in the small intestinal wall or contents. Methods: A model was developed for calculation of the self-dose and cross-dose from activity in the intestinal wall or contents. The small intestine was modeled as a cylinder with 2 different wall thicknesses and with an infinite length. Calculations were performed for various mucus thicknesses. S values were calculated using the EGS4 Monte Carlo simulation package with the PRESTA algorithm and the simulation results were integrated over the depth of the radiosensitive cells. The cross-organ dose was calculated by summing the dose contributions from other intestinal segments. Calculations of S values for self-dose and cross-dose were made for monoenergetic electrons, 0.050–10 MeV, and for the radionuclides 99mTc, 111In, 131I, 67Ga, 90Y, and 211At. Results: The self-dose S value from activity located in the small intestinal wall is considerably greater than the S values for self-dose from the contents and the cross-dose from wall and contents except for high electron energies. For all radionuclides investigated and for electrons 0.10–0.20 MeV and 8–10 MeV in energy, the cross-dose from activity in the contents is higher than the self-dose from the contents. The mucus thickness affects the S value when the activity is located in the contents. Conclusion: A dosimetric model for the small intestine was developed that takes into consideration the localization of the radiopharmaceutical in the intestinal wall or in the contents. It also calculates the contribution from self-dose and cross-dose. With this model, more accurate calculations of absorbed dose to radiation-sensitive cells in the intestine are possible.},
  author       = {Jönsson, Lena M and Liu, Xiaowei and Jönsson, Bo-Anders and Ljungberg, Michael and Strand, Sven-Erik},
  issn         = {0161-5505},
  keyword      = {intestine,EGS4,radiation dosimetry,Monte Carlo simulations,cross-dose},
  language     = {eng},
  number       = {12},
  pages        = {1657--1664},
  publisher    = {Society of Nuclear Medicine},
  series       = {Journal of Nuclear Medicine},
  title        = {A dosimetry model for the small intestine incorporating intestinal wall activity and cross-doses.},
  volume       = {43},
  year         = {2002},
}