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Calculation of radiation dose enhancement factors for dose enhancement therapy of brain tumours

1992; IOP Publishing; Volume: 37; Issue: 2 Linguagem: Inglês

10.1088/0031-9155/37/2/010

1361-6560

Timothy D. Solberg, Keisuke S. Iwamoto, Amos Norman,

Medical Imaging Techniques and Applications

When brain tumours are loaded with iodinated contrast media (CM) and exposed to x-rays, the photoelectrons, Auger electrons and fluorescent x-rays from the iodine enhance the radiation dose absorbed by the tumour. A modified CT scanner, the CTX, can be used to localize the tumour and to deliver the dose enhancement therapy. Monte Carlo calculations are presented here of the central-axis radiation depth dose in a brain containing a tumour loaded with an iodine concentration of 5 mg ml-1 and irradiated with the CTX operated at various kV settings. The dose enhancement factor (DEF) is also calculated for various field sizes and for 5 mg ml-1 of gadolinium in the tumour when the CTX is operated at 140 kV. The calculated values of the DEF are close to published experimental results.