Influence of field-of-view and section thickness of diagnostic imaging on thermal neutron flux estimation in dose-planning for boron neutron capture therapy
- 30 Downloads
Radiation treatment planning for boron neutron capture therapy (BNCT) often uses computed tomography (CT) images reconstructed utilizing various section thickness and field-of-view (FOV) settings. Based on these images, a geometrical model is created by setting material regions manually over the pixel space defined in the treatment planning system. Thus, a setting difference of several pixels inevitably occurs in creation of the model. The influence of different section thicknesses and FOVs on thermal neutron flux estimations using the BNCT planning system was studied here. A virtual phantom was created with six FOV sizes on the planning system. The position of the irradiated side of the phantom surface was shifted by 1–10 pixels along the beam direction or in the opposite direction to simulate the material setting on different pixels in the geometric model. The effect of a one-pixel-difference setting on thermal neutron flux increased with increasing FOV size. Next, a cylindrical and a spherical phantom were scanned, and each CT image was reconstructed with six FOV sizes and seven section thicknesses. The flux changes for all conditions were compared, with an allowable error rate of ± 0.05, as in conventional X-ray radio therapy. The accuracy of neutron flux estimations was also evaluated by repeating the calculation procedures with CT scanning 5 or 10 times, and was found to be mostly within 0.03, except for the FOV-500 condition (0.074). These results suggested that a smaller FOV and section thickness with realistic conditions could improve evaluation accuracy of the thermal neutron flux for BNCT.
KeywordsBoron neutron capture therapy Epi-thermal neutron flux Field-of-view Section thickness Thermal neutron flux Treatment planning
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
Research involving human participants and animals
This article does not contain any studies with human participants performed. This article does not contain any studies with animals performed.
Informed consent for this study was not required because no research involving human participants was undertaken by any of the authors.
- 6.Rassow J, Pöller F, Steinberg F, Meissner P. Physical and tumor biological aspects and calculation model of dosage in boron neutron capture therapy (BNCT). Strahlenther Onkol. 1993;169:7–17.Google Scholar
- 10.Tsukihara M, Noto Y, Sasamoto R, Hayakawa T, Saito M. Initial implementation of the conversion from the energy-subtracted CT number to electron density in tissue inhomogeneity corrections: an anthropomorphic phantom study of radiotherapy treatment planning. Med Phys. 2015;42:1378–88.CrossRefGoogle Scholar
- 11.Wessol DE, et al. SERA: simulation environment for radiotherapy applications user’s manual version 1C0. INEEL/EXT-02-00698 (2002).Google Scholar
- 15.ICRU Report 46. Photon, electron, proton, and neutron interaction data for body tissues. Bethesda: International Commission on Radiation Units and Measurements; 1992.Google Scholar
- 17.Chadha M, Capala J, Coderre JA, Elowitz EH, Iwai J, Joel DD, Liu HB, Wielopolski L, Chanana AD. Boron neutron-capture therapy (BNCT) for glioblastoma multiforme (GBM) using the epithermal neutron beam at the Brookhaven National Laboratory. Int J Radiat Oncol Biol Phys. 1998;40:829–34.CrossRefGoogle Scholar