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Impact of collimator leaf width and treatment technique on stereotactic radiosurgery and radiotherapy plans for intra- and extracranial lesions.

dc.contributor.author Kirkpatrick, John
dc.contributor.author Chang, Zheng
dc.contributor.author Yin, Fang-Fang
dc.contributor.author Wang, Zhiheng
dc.contributor.author Wu, Qingrong
dc.contributor.author Meyer, Jeffrey J
dc.contributor.author Lu, Mei
dc.contributor.author Huntzinger, Calvin
dc.date.accessioned 2019-10-04T16:07:10Z
dc.date.available 2019-10-04T16:07:10Z
dc.date.issued 2009-01-21
dc.identifier 1748-717X-4-3
dc.identifier.issn 1748-717X
dc.identifier.issn 1748-717X
dc.identifier.uri https://hdl.handle.net/10161/19401
dc.description.abstract BACKGROUND: This study evaluated the dosimetric impact of various treatment techniques as well as collimator leaf width (2.5 vs 5 mm) for three groups of tumors -- spine tumors, brain tumors abutting the brainstem, and liver tumors. These lesions often present challenges in maximizing dose to target volumes without exceeding critical organ tolerance. Specifically, this study evaluated the dosimetric benefits of various techniques and collimator leaf sizes as a function of lesion size and shape. METHODS: Fifteen cases (5 for each site) were studied retrospectively. All lesions either abutted or were an integral part of critical structures (brainstem, liver or spinal cord). For brain and liver lesions, treatment plans using a 3D-conformal static technique (3D), dynamic conformal arcs (DARC) or intensity modulation (IMRT) were designed with a conventional linear accelerator with standard 5 mm leaf width multi-leaf collimator, and a linear accelerator dedicated for radiosurgery and hypofractionated therapy with a 2.5 mm leaf width collimator. For the concave spine lesions, intensity modulation was required to provide adequate conformality; hence, only IMRT plans were evaluated using either the standard or small leaf-width collimators.A total of 70 treatment plans were generated and each plan was individually optimized according to the technique employed. The Generalized Estimating Equation (GEE) was used to separate the impact of treatment technique from the MLC system on plan outcome, and t-tests were performed to evaluate statistical differences in target coverage and organ sparing between plans. RESULTS: The lesions ranged in size from 2.6 to 12.5 cc, 17.5 to 153 cc, and 20.9 to 87.7 cc for the brain, liver, and spine groups, respectively. As a group, brain lesions were smaller than spine and liver lesions. While brain and liver lesions were primarily ellipsoidal, spine lesions were more complex in shape, as they were all concave. Therefore, the brain and the liver groups were compared for volume effect, and the liver and spine groups were compared for shape. For the brain and liver groups, both the radiosurgery MLC and the IMRT technique contributed to the dose sparing of organs-at-risk(OARs), as dose in the high-dose regions of these OARs was reduced up to 15%, compared to the non-IMRT techniques employing a 5 mm leaf-width collimator. Also, the dose reduction contributed by the fine leaf-width MLC decreased, as dose savings at all levels diminished from 4 - 11% for the brain group to 1 - 5% for the liver group, as the target structures decreased in volume. The fine leaf-width collimator significantly improved spinal cord sparing, with dose reductions of 14 - 19% in high to middle dose regions, compared to the 5 mm leaf width collimator. CONCLUSION: The fine leaf-width MLC in combination with the IMRT technique can yield dosimetric benefits in radiosurgery and hypofractionated radiotherapy. Treatment of small lesions in cases involving complex target/OAR geometry will especially benefit from use of a fine leaf-width MLC and the use of IMRT.
dc.language eng
dc.publisher Springer Nature
dc.relation.ispartof Radiation oncology (London, England)
dc.relation.isversionof 10.1186/1748-717X-4-3
dc.subject Humans
dc.subject Spinal Neoplasms
dc.subject Liver Neoplasms
dc.subject Brain Neoplasms
dc.subject Radiosurgery
dc.subject Radiotherapy Planning, Computer-Assisted
dc.subject Tumor Burden
dc.subject Retrospective Studies
dc.subject Radiation Dosage
dc.subject Dose-Response Relationship, Radiation
dc.subject Computer Simulation
dc.subject Radiation Equipment and Supplies
dc.title Impact of collimator leaf width and treatment technique on stereotactic radiosurgery and radiotherapy plans for intra- and extracranial lesions.
dc.type Journal article
duke.contributor.id Kirkpatrick, John|0265323
duke.contributor.id Chang, Zheng|0456928
duke.contributor.id Yin, Fang-Fang|0334491
duke.contributor.id Wang, Zhiheng|0288445
duke.contributor.id Wu, Qingrong|0378401
dc.date.updated 2019-10-04T16:07:06Z
pubs.begin-page 3
pubs.issue 1
pubs.organisational-group School of Medicine
pubs.organisational-group Duke
pubs.organisational-group Duke Kunshan University Faculty
pubs.organisational-group Duke Kunshan University
pubs.organisational-group Duke Cancer Institute
pubs.organisational-group Institutes and Centers
pubs.organisational-group Radiation Oncology
pubs.organisational-group Clinical Science Departments
pubs.organisational-group Neurosurgery
pubs.publication-status Published
pubs.volume 4
duke.contributor.orcid Yin, Fang-Fang|0000-0002-2025-4740


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