Document Detail


Verification of intensity modulated profiles using a pixel segmented liquid-filled linear array.
MedLine Citation:
PMID:  16723758     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
A liquid isooctane (C8H18) filled ionization chamber linear array developed for radiotherapy quality assurance, consisting of 128 pixels (each of them with a 1.7 mm pitch), has been used to acquire profiles of several intensity modulated fields. The results were compared with film measurements using the gamma test. The comparisons show a very good matching, even in high gradient dose regions. The volume-averaging effect of the pixels is negligible and the spatial resolution is enough to verify these regions. However, some mismatches between the detectors have been found in regions where low-energy scattered photons significantly contribute to the total dose. These differences are not very important (in fact, the measurements of both detectors are in agreement using the gamma test with tolerances of 3% and 3 mm in most of those regions), and may be associated with the film energy dependence. In addition, the linear array repeatability (0.27% one standard deviation) is much better than the film one ( approximately 3%). The good repeatability, small pixel size and high spatial resolution make the detector ideal for the real time profile verification of high gradient beam profiles like those present in intensity modulated radiation therapy and radiosurgery.
Authors:
J Pardo; J V Roselló; F Sánchez-Doblado; F Gómez
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't     Date:  2006-05-17
Journal Detail:
Title:  Physics in medicine and biology     Volume:  51     ISSN:  0031-9155     ISO Abbreviation:  Phys Med Biol     Publication Date:  2006 Jun 
Date Detail:
Created Date:  2006-05-25     Completed Date:  2006-08-25     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0401220     Medline TA:  Phys Med Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  N211-9     Citation Subset:  IM    
Affiliation:
Departamento de Física de Partículas, Facultade de Física, Universidade de Santiago de Compostela, Spain. juanpm@usc.es
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MeSH Terms
Descriptor/Qualifier:
Computer Graphics*
Film Dosimetry / instrumentation,  methods
Humans
Quality Assurance, Health Care*
Radiography / instrumentation,  methods*
Radiometry / instrumentation,  methods*
Radiosurgery / instrumentation,  methods
Radiotherapy / instrumentation,  methods
Radiotherapy Dosage / standards*
Reproducibility of Results
Sensitivity and Specificity
Sensory Aids

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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