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The influence of air humidity on an unsealed ionization chamber in a linear accelerator

Blad, Börje LU ; Nilsson, Per LU and Knöös, Tommy LU (1996) In Physics in Medicine and Biology 41(11). p.2541-2548
Abstract
The safe and accurate delivery of the prescribed absorbed dose is the central function of the dose monitoring and beam stabilization system in a medical linear accelerator. The absorbed dose delivered to the patient during radiotherapy is often monitored by a transmission ionization chamber. Therefore it is of utmost importance that the chamber behaves correctly. We have noticed that the sensitivity of an unsealed chamber in a Philips SL linear accelerator changes significantly, especially during and after the summer season. The reason for this is probably a corrosion effect of the conductive plates in the chamber due to the increased relative humidity during hot periods. We have found that the responses of the different ion chamber plates... (More)
The safe and accurate delivery of the prescribed absorbed dose is the central function of the dose monitoring and beam stabilization system in a medical linear accelerator. The absorbed dose delivered to the patient during radiotherapy is often monitored by a transmission ionization chamber. Therefore it is of utmost importance that the chamber behaves correctly. We have noticed that the sensitivity of an unsealed chamber in a Philips SL linear accelerator changes significantly, especially during and after the summer season. The reason for this is probably a corrosion effect of the conductive plates in the chamber due to the increased relative humidity during hot periods. We have found that the responses of the different ion chamber plates change with variations in air humidity and that they do not return to their original values when the air humidity is returned to ambient conditions. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Physics in Medicine and Biology
volume
41
issue
11
pages
2541 - 2548
publisher
IOP Publishing
external identifiers
  • pmid:8938044
  • scopus:0029976849
ISSN
1361-6560
DOI
10.1088/0031-9155/41/11/021
language
English
LU publication?
yes
id
ea78e51c-cc00-471a-92d8-e76be229e0f6 (old id 1110181)
date added to LUP
2008-07-22 09:20:11
date last changed
2017-01-01 04:34:24
@article{ea78e51c-cc00-471a-92d8-e76be229e0f6,
  abstract     = {The safe and accurate delivery of the prescribed absorbed dose is the central function of the dose monitoring and beam stabilization system in a medical linear accelerator. The absorbed dose delivered to the patient during radiotherapy is often monitored by a transmission ionization chamber. Therefore it is of utmost importance that the chamber behaves correctly. We have noticed that the sensitivity of an unsealed chamber in a Philips SL linear accelerator changes significantly, especially during and after the summer season. The reason for this is probably a corrosion effect of the conductive plates in the chamber due to the increased relative humidity during hot periods. We have found that the responses of the different ion chamber plates change with variations in air humidity and that they do not return to their original values when the air humidity is returned to ambient conditions.},
  author       = {Blad, Börje and Nilsson, Per and Knöös, Tommy},
  issn         = {1361-6560},
  language     = {eng},
  number       = {11},
  pages        = {2541--2548},
  publisher    = {IOP Publishing},
  series       = {Physics in Medicine and Biology},
  title        = {The influence of air humidity on an unsealed ionization chamber in a linear accelerator},
  url          = {http://dx.doi.org/10.1088/0031-9155/41/11/021},
  volume       = {41},
  year         = {1996},
}