Tissue Compensation Approach with Perspex Slab for External Beam Radiotherapy

Authors

  • Samuel Nii Adu Tagoe  Department of Physics, School of Physical Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana
  • Samuel Yeboah Mensah  Department of Physics, School of Physical Sciences, College of Agriculture and Natural Sciences, University of Cape Coast, Cape Coast, Ghana
  • John Justice Fletcher  Department of Applied Physics, University for Development Studies, Navrongo Campus, Navrongo, Ghana
  • Evans Sasu  National Centre for Radiotherapy Oncology and Nuclear Medicine, Korle Bu Teaching Hospital, Accra, Ghana

Keywords:

Perspex, compensating filter, bolus, telecobalt machine, missing tissue compensation

Abstract

Skin sparing is retained by representing bolus for tissue deficit compensation with a compensator which is placed at certain distance from the skin. Owing to the position of the compensator, the shape of the compensator needs to be adjusted to account for beam divergence and reduction in scattered radiation contribution to dose at any point within the patient, such that dose distribution within the patient would be the same as that obtained with the bolus. Procedures for determining the shape and constructing Perspex (Polymethylmethaneacrylate) missing tissue compensators had been outlined for a telecobalt machine based on outputs of a forward planning treatment planning system, used to simulate irradiation geometries with boluses. The proposed approach considered the influences of treatment parameters: field size, treatment depth and bolus thickness to be applied in the determination of the required compensator material thickness along a particular ray-line. A semi-empirical algorithm based on beam data measured in full scatter water phantom with and without the compensator material, was proposed for the conversion of a bolus thickness to compensator material thickness such the dose distribution within a patient remain the same. Outputs of the proposed approach compared favourably well with those of the treatment planning system with discrepancies less than or equal to ± 3% (mean of 1.99 ± 0.64 %). The use of the proposed approach for clinical application is recommended.

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International Journal of Scientific Research in Science, Engineering and Technology

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Published

2018-07-30

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Volume 4, Issue 9, July-August-2018

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Research Articles

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How to Cite

[1]
Samuel Nii Adu Tagoe, Samuel Yeboah Mensah, John Justice Fletcher, Evans Sasu, " Tissue Compensation Approach with Perspex Slab for External Beam Radiotherapy, International Journal of Scientific Research in Science, Engineering and Technology(IJSRSET), Print ISSN : 2395-1990, Online ISSN : 2394-4099, Volume 4, Issue 9, pp.159-172, July-August-2018.