Linked Life Data

19223841

Source:http://linkedlifedata.com/resource/pubmed/id/19223841

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
2009-2-19
pubmed:abstractText
Accurate multileaf collimator (MLC) leaf positioning plays an essential role in the effective implementation of intensity modulated radiation therapy (IMRT). This work evaluates the sensitivity of current patient-specific IMRT quality assurance (QA) procedures to minor MLC leaf positioning errors. Random errors of up to 2 mm and systematic errors of +/-1 mm and +/-2 mm in MLC leaf positions were introduced into 8 clinical IMRT patient plans (totaling 53 fields). Planar dose distributions calculated with modified plans were compared to dose distributions measured with both radiochromic films and a diode matrix. The agreement between calculation and measurement was evaluated using both absolute distance-to-agreement (DTA) analysis and gamma index with 2%/2 mm and 3%/3 mm criteria. It was found that both the radiochromic film and the diode matrix could only detect systematic errors on the order of 2 mm or above. The diode array had larger sensitivity than film due to its excellent detector response (such as small variation, linear response, etc.). No difference was found between DTA analysis and gamma index in terms of the sensitivity to MLC positioning errors. Higher sensitivity was observed with 2%/2 mm than with 3%/3 mm in general. When using the diode array and 2%/2 mm criterion, the IMRT QA procedure showed strongest sensitivity to MLC position errors and, at the same time, achieved clinically acceptable passing rates. More accurate dose calculation and measurement would further enhance the sensitivity of patient-specific IMRT QA to MLC positioning errors. However, considering the significant dosimetric effect such MLC errors could cause, patient-specific IMRT QA should be combined with a periodic MLC QA program in order to guarantee the accuracy of IMRT delivery.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:issn
1526-9914
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
10
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2915
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
On the sensitivity of patient-specific IMRT QA to MLC positioning errors.
pubmed:affiliation
Department of Radiation Oncology, University of Florida, Gainesville, FL 32610-0385, USA. yan@ufl.edu.
pubmed:publicationType
Journal Article