Abstract:
PURPOSE:To quantify the effects of combining layer-based repainting and respiratory gating as a strategy to mitigate the dosimetric degradation caused by the interplay effect between a moving target and dynamic spot-scanning proton delivery. METHODS:An analytic routine modeled three-dimensional dose distributions of pencil-beam proton plans delivered to a moving target. Spot positions and weights were established for a single field to deliver 100 cGy to a static, 15-cm deep, 3-cm radius spherical clinical target volume with a 1-cm isotropic internal target volume expansion. The interplay effect was studied by modeling proton delivery from a clinical synchrotron-based spot scanning system and respiratory target motion, patterned from surrogate patient breathing traces. Motion both parallel and orthogonal to the beam scanning direction was investigated. Repainting was modeled using a layer-based technique. For each of 13 patient breathing traces, the dose from 20 distinct delivery schemes (combinations of four gate window amplitudes and five repainting techniques) was computed. Delivery strategies were inter-compared based on target coverage, dose homogeneity, high dose spillage, and delivery time. RESULTS:Notable degradation and variability in plan quality were observed for ungated delivery. Decreasing the gate window reduced this variability and improved plan quality at the expense of longer delivery times. Dose deviations were substantially greater for motion orthogonal to the scan direction when compared with parallel motion. Repainting coupled with gating was effective at partially restoring dosimetric coverage at only a fraction of the delivery time increase associated with very small gate windows alone. Trends for orthogonal motion were similar, but more complicated, due to the increased severity of the interplay. CONCLUSIONS:Layer-based repainting helps suppress the interplay effect from intra-gate motion, with only a modest penalty in delivery time. The magnitude of the improvement in target coverage is strongly influenced by individual patient breathing patterns and the tumor motion trajectory.
journal_name
J Appl Clin Med Physjournal_title
Journal of applied clinical medical physicsauthors
Johnson JE,Herman MG,Kruse JJdoi
10.1002/acm2.12702subject
Has Abstractpub_date
2019-09-01 00:00:00pages
69-77issue
9issn
1526-9914journal_volume
20pub_type
杂志文章abstract::We have developed a method to improve the setup accuracy of a Varian Clinac 6/100 couch for delivering conformal arc therapy using a tertiary micro multileaf collimator (MLC) system. Several immobilization devices have been developed to improve the mechanical stability and isocenter alignment of the couch: turn-knob h...
journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
doi:10.1120/jacmp.v5i3.2026
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journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
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journal_title:Journal of applied clinical medical physics
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journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
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journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
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更新日期:2018-11-01 00:00:00
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journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
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journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
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journal_title:Journal of applied clinical medical physics
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journal_title:Journal of applied clinical medical physics
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journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
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journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
doi:10.1120/jacmp.v14i6.4239
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journal_title:Journal of applied clinical medical physics
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更新日期:2006-11-28 00:00:00
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journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
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更新日期:2018-07-01 00:00:00
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journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
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更新日期:2020-03-01 00:00:00
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journal_title:Journal of applied clinical medical physics
pub_type: 杂志文章
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更新日期:2017-11-01 00:00:00
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journal_title:Journal of applied clinical medical physics
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更新日期:2016-11-08 00:00:00
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journal_title:Journal of applied clinical medical physics
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更新日期:2018-11-01 00:00:00
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journal_title:Journal of applied clinical medical physics
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journal_title:Journal of applied clinical medical physics
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journal_title:Journal of applied clinical medical physics
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journal_title:Journal of applied clinical medical physics
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