Abstract：
:The reproducibility of polyacrylamide gel (PAG) dosimetry has been evaluated when used to verify two radiotherapy treatment plans of increasing complexity. The plans investigated were a three-field coplanar arrangement, using the linac jaws for field shaping, and a four-field, conformal, non-coplanar plan using precision-cast lead alloy shielding blocks. Each treatment was performed three times using phantoms and calibration gels manufactured in-house. Two phantoms were specially designed for this work to aid accurate positioning of the gels for irradiation and imaging. All gels were imaged post-irradiation using a Siemens Vision 1.5T MR scanner. T2 relaxation images were calibrated to absorbed dose distributions using a number of smaller calibration vessels to produce distribution maps of relative dose. The relative dose distributions were found to be reproducible, with the standard deviation on the mean areas enclosed by the > or = 50% isodose lines measured in three orthogonal planes being 6.4% and 4.1% for the coplanar and non-coplanar plans respectively. The measured distributions were also consistent with those planned, with isodose lines generally agreeing to within a few millimetres. However, the measured absolute doses were on average 23.5% higher than those planned. Although the polyacrylamide gel dosimetry technique has some limitations, particularly when calibrating distributions to absolute dose, the ability to resolve sharp dose gradients in three dimensions with millimetre precision is invaluable when verifying complex conformal treatment plans, where avoidance of proximal, critical structures is a treatment criterion.
journal_name
Phys Med Bioljournal_title
Physics in medicine and biologyauthors
Cosgrove VP,Murphy PS,McJury M,Adams EJ,Warrington AP,Leach MO,Webb Sdoi
10.1088/0031-9155/45/5/309subject
Has Abstractpub_date
2000-05-01 00:00:00pages
1195-210issue
5eissn
0031-9155issn
1361-6560journal_volume
45pub_type
杂志文章abstract：:The use of thermographic techniques has increased as infrared detector technology has evolved and improved. For laser-tissue interactions, thermal cameras have been used to monitor the thermal response of tissue to pulsed and continuous wave irradiation. It is important to note that the temperature indicated by the th...
journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/45/2/319
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journal_title：Physics in medicine and biology
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/54/6/014
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/46/2/307
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/51/21/012
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/26/1/011
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/44/8/311
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/45/12/310
更新日期：2000-12-01 00:00:00
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/50/4/001
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/51/10/004
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/56/22/017
更新日期：2011-11-21 00:00:00
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/0031-9155/44/2/008
更新日期：1999-02-01 00:00:00
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journal_title：Physics in medicine and biology
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
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journal_title：Physics in medicine and biology
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journal_title：Physics in medicine and biology
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journal_title：Physics in medicine and biology
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journal_title：Physics in medicine and biology
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journal_title：Physics in medicine and biology
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journal_title：Physics in medicine and biology
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
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journal_title：Physics in medicine and biology
pub_type： 杂志文章
doi：10.1088/1361-6560/aba08c
更新日期：2020-06-26 00:00:00
