Dose distributions of a proton beam for eye tumor therapy: Hybrid pencil-beam ray-tracing calculations
- Hahn-Meitner-Institut Berlin, 14109 Berlin (Germany)
For the case of eye tumor therapy with protons, improvements are introduced compared to the standard dose calculation which implies straight-line optics and the constant-density assumption for the eye and its surrounding. The progress consists of (i) taking account of the lateral scattering of the protons in tissue by folding the entrance fluence distribution with the pencil beam distribution widening with growing depth in the tissue, (ii) rescaling the spread-out Bragg peak dose distribution in water with the radiological path length calculated voxel by voxel on ray traces through a realistic density matrix for the treatment geometry, yielding a trajectory dependence of the geometrical range. Distributions calculated for some specific situations are compared to measurements and/or standard calculations, and differences to the latter are discussed with respect to the requirements of therapy planning. The most pronounced changes appear for wedges placed in front of the eye, causing additional widening of the lateral falloff. The more accurate prediction of the dose dependence at the field borders is of interest with respect to side effects in the risk organs of the eye.
- OSTI ID:
- 20775097
- Journal Information:
- Medical Physics, Vol. 33, Issue 3; Other Information: DOI: 10.1118/1.2168067; (c) 2006 American Association of Physicists in Medicine; Country of input: International Atomic Energy Agency (IAEA); ISSN 0094-2405
- Country of Publication:
- United States
- Language:
- English
Similar Records
Experimental evaluation of a spatial resampling technique to improve the accuracy of pencil-beam dose calculation in proton therapy
TH-C-BRD-03: Determining the Optimal Collimator Position for Collimated Pencil Beam Scanning Proton Therapy