title: Calculation of radiation dose enhancement factors for dose enhancement therapy of brain tumours.
abstract: 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.
authors.affiliation: Department of Radiation Oncology, University of California, Los Angeles 90024.
authors.forename: T D
authors.initials: TD
authors.lastname: Solberg
authors.forename: K S
authors.initials: KS
authors.lastname: Iwamoto
authors.forename: A
authors.initials: A
authors.lastname: Norman
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000188:drug therapy / Q000532:radiotherapy*; D003131:Combined Modality Therapy; D003287:Contrast Media / Q000627:therapeutic use; D004285:Dogs; D006801:Humans; D007455:Iodine / Q000627:therapeutic use*; D011879:Radiotherapy Dosage
chemical_list: D003287:Contrast Media; D007455:Iodine