External radiotherapy in macular degeneration: our technique, dosimetric calculation, and preliminary results.
OBJECTIVE
This study was performed to determine the toxicity and efficacy of external-beam radiotherapy in patients with age-related subfoveal neovascularization.


METHODS
Between January 1996 and September 1996, 25 patients with a mean age of 70.5 (60-84) years were enrolled. All patients underwent fluorescein angiographic evaluation and documentation of their neovascular disease prior to irradiation. A total of 25 patients were treated with a total dose of 12 Gy in 6 fractions over 8 days. We used a lens-sparing technique and patients were treated with a single lateral 6-MV photon beam. To assess the risk of radiation carcinogenesis after treatment of age-related subfoveal neovascularization, we estimated the effective dose for a standard patient on the basis of tissue-weighting factors as defined by the International Commission on Radiological Protection (ICRP). The calculations were made with TLD on a male randophantom. The lens dose was found to be 0.217 Gy per fraction.


RESULTS
No significant acute morbidity was noted. Visual acuity was maintained or improved in 76% and 80% of treated patients at their 1- and 3-month follow-up examinations, respectively. On angiographic imaging, there was stabilization of subfoveal neovascular membranes in 23 patients (92%) at 3 months after irradiation.


CONCLUSIONS
Our observations on these 25 patients in this study indicate that many patients will have improved or stable vision after radiotherapy treatment with low-dose irradiation.
Akmansu
M
M
Department of Radiation Oncology, Gazi University Medical Faculty, Ankara, Turkey.
Dîrîcan
B
B
Oztürk
B
B
Egehan
I
I
Subaşi
M
M
Or
M
M
D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D008268:Macular Degeneration / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D011874:Radiometry; D011879:Radiotherapy Dosage