Dosimetric consequences of rotational setup errors with direct simulation in a treatment planning system for fractionated stereotactic radiotherapy

• DOI: 10.1120/jacmp.v12i3.3422
• Publication Date: 2017-02-27T22:30:32Z
• Authors: Jean L. Peng; Chihray Liu; Yu Chen; Robert J. Amdur; Kenneth Vanek; Jonathan G. Li
• Keywords: Margin (machine learning)

The purpose was to determine dose‐delivery errors resulting from systematic rotational setup for fractionated stereotactic radiotherapy using direct simulation in a treatment planning system. Ten patients with brain tumors who received intensity‐modulated had dose distributions re‐evaluated assess the impact of errors. dosimetric effect simulated by rotating images and contours 3 matrix. Combined residual translation 1 mm along each axis were simulated. Dosimetric effects rotated evaluated recomputing compared original plan. mean volume CTV that prescription decreased (original) , . Minimal changes cold hot spots seen CTV. In general, increase volumes organs at risk (OARs) receiving tolerance doses small did not exceed tolerance, except cases where OARs close proximity PTV. For intracranial treated IMRT CTV‐to‐PTV margin mm, 3° or less didn't decrease coverage than 95% most cases. However, large targets irregular elliptical shapes, target significantly as 5° more present. Our results indicate margins are warranted even absence translational account Rotational should be carefully clinical involving tumor sizes shape, well when isocenter is away center PTV volumes. PACS number: 87.53.Bn