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Sci—Fri AM(2): Brachy—08: Dosimetric Comparison of Different Radiation Techniques in the Treatment of Juxtapapillary Choroidal Melanoma
Author(s) -
Heydarian M,
vanProoijen M,
BeikiArdakani A,
Ruschin M,
Sahgal A,
Krema H,
Payne D,
Laperriere N
Publication year - 2009
Publication title -
medical physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.473
H-Index - 180
eISSN - 2473-4209
pISSN - 0094-2405
DOI - 10.1118/1.3244200
Subject(s) - medicine , nuclear medicine , choroidal melanoma , brachytherapy , dosimetry , radiation therapy , optic neuropathy , melanoma , ophthalmology , radiology , optic nerve , cancer research
Purpose/Objective(s): To compare dosimetric parameters of linac‐based stereotactic radiotherapy (LB‐SRT), to Gamma Knife Perfexion (GK‐SRT) and125 Iodine Brachytherapy (IBT) in treating Juxtapapillary Choroidal Melanoma (JCM). Materials/Methods: Three JCM cases of small, medium and large size tumours, based on the COMS definition, which previously received LB‐SRT using our current protocol of 70 Gy in 5 fractions over 10 days, were selected and re‐planned on GK‐SRT and IBT. Dosimetric parameters chosen for comparison were tumour dose coverage, including maximum, minimum and mean doses, as well as dose to tumour base and apex. Dose to organs at risk, such as optic disc, lens and D70 of the involved eye were also compared. All doses were normalized such that 99% of the tutors received at least a dose of 70 Gy. Tumour control and treatment complications, such as radiation retinopathy, optic neuropathy and neovascular glaucoma, have been reported that can be directly related to the above dosimetric parameters. Results: Overall tumour mean doses by LB‐SRT, GK‐SRT and IBT were 73.11, 98.86 and 117.72 Gy, and maximum doses 74.33, 137.12 and 229.05 Gy, respectively. Corresponding overall doses to the lens center were 2.24, 8.75 and 12.49 Gy, and D70 of the eye were 17.91, 10.01 and 13.55 Gy, respectively. Conclusion: In this study we have shown that LB‐SRT, GK‐SRT and IBT provide comparable treatment for Choroidal Melanoma. Linac‐based SRT delivers most uniform dose to the tumour and smaller dose to the lens and anterior chamber, however has a higher D70, compared to the other two.