Palladium-103 plaque radiation therapy for macular degeneration: results of a 7 year study.

AIM: To report 7 year results of ophthalmic plaque radiotherapy for exudative macular degeneration. METHODS: In a phase I clinical trial, 30 patients (31 eyes) were treated with ophthalmic plaque irradiation for subfoveal exudative macular degeneration. Radiation was delivered to a mean 2 mm from the inner sclera (range 1.2-2.4) prescription point calculated along the central axis of the plaque. The mean prescription dose was 17.62 Gy (range 12.5-24) delivered over 34 hours (range 18-65). Early Treatment Diabetic Retinopathy Study (ETDRS) type standardised visual acuity determinations, ophthalmic examinations, and angiography were performed before and after treatment. Clinical evaluations were performed in a non-randomised and unmasked fashion. RESULTS: At 33.3 months (range 3-4), 17 of 31 (55%) eyes had lost 3 or more lines of vision on the ETDRS chart, five (16%) had improved 3 or more lines, and the remaining nine (29%) were within 2 lines of their pretreatment visual acuity measurement. Overall, 45% of patients were within or improved more than 2 lines of their initial visual acuity. Five eyes developed macular scars, eight developed subsequent neovascularisation or haemorrhage, and three progressed through therapy. Two patients were lost to follow up. The most common finding of patients followed for 6 or more months (n=18 of 29 (62%)) was regression or stabilisation of the exudative process. No radiation retinopathy, optic neuropathy, or cataracts could be attributed to irradiation. CONCLUSION: Ophthalmic plaque radiation can be used to treat exudative macular degeneration. At the dose and dose rates employed, most patients experienced decreased exudation or stabilisation of their maculas. No sight limiting radiation complications were noted during 7 year follow up. Owing to the variable natural course of this disease, a prospective randomised clinical trial should be performed to evaluate the efficacy of plaque radiation therapy for exudative macular degeneration.

Diode-light transillumination for ophthalmic plaque localization around juxtapapillary choroidal melanomas.

PURPOSE: An evaluation of plaque-mounted diode-light transillumination (DLT) for localization of episcleral plaques beneath juxtapapillary tumors. METHODS AND MATERIALS: Two patients scheduled for radiotherapy for juxtapapillary melanomas were offered DLT as an additional method of ophthalmic plaque localization. Plaques were constructed by affixing 4 non-heat producing, light-emitting diodes with their apertures flush with the episcleral outer surface of the plaque's rim. Bio-implantable epoxy was used to encapsulate the electronic components. Then the plaques were loaded with 103Pd seeds. After the eye-plaques were sewn to the episclera covering the base of the intraocular tumors; the diode-lights were illuminated, viewed and recorded. Photodocumentation of the relative position of the 4 lights around tumor's base was obtained in both cases. RESULTS: Digital images of plaque-mounted diode retro-transillumination were obtained. No evidence of diode-light toxicity was noted. Both tumors were found to be covered by the ophthalmic plaques. CONCLUSION: Juxtapapillary tumors are often difficult or impossible to visualize with standard transillumination techniques and have been associated with poor local control rates. We have developed plaque-mounted DLT in an effort to improve ophthalmic plaque localization. Retrobulbar transillumination was viewed by indirect ophthalmoscopy and recorded with video-imaging. This technique provides unique photographic documentation of episcleral plaque localization beneath juxtapapillary tumors.

Palladium-103 plaque radiotherapy for choroidal melanoma: results of a 7-year study.

OBJECTIVE: To describe the first clinical experience with palladium-103 (103Pd) ophthalmic plaque radiotherapy for choroidal melanoma. DESIGN: Phase-I (nonrandomized) clinical trial. PARTICIPANTS: Eighty patients with uveal melanomas were diagnosed by clinical examination, found to be negative for metastatic disease, and offered 103Pd radioactive plaque treatment. Nine patients were concurrently treated with microwave hyperthermia. INTERVENTION: Palladium-103 ophthalmic plaque radiotherapy was employed for each patient. Eye plaques were sewn to the episclera to cover the base of the intraocular tumor, radiation was continuously delivered over 5 to 7 days, and then the plaques were removed. A mean apical dose of 81 Gy was delivered. MAIN OUTCOME MEASURES: The authors evaluated the ease of use of 103Pd seeds within standard gold eye plaques. Patient-related outcomes were control of tumor growth, change in visual acuity, the development of radiation damage (retinopathy, optic neuropathy, and cataract), and metastatic disease. RESULTS: From September 1990 to December 1997, 80 patients were treated with 103Pd and followed for an average of 38 months. Two patients were lost to follow-up. During this time, the authors found that 103Pd seeds were equivalent to iodine-125 (125I) with respect to plaque manufacture and ease of dosimetric calculations. Two patients in this series were treated for tumor recurrence after 125I plaque radiotherapy. They both failed secondary 103Pd treatment and were enucleated. When 103Pd was used as a primary treatment, it controlled the growth of 75 of 78 tumors (96%). Overall, there have been six enucleations: three failures of primary treatment, two failures of retreatment, and one for neovascular glaucoma. Visual acuity evaluations at the 36-month follow-up visit (including the enucleated patients) revealed that 38% of eyes had decreased 3 or more lines of vision, and 77% were 20/200 or better. CONCLUSION: Palladium-103 plaque radiotherapy can be used to treat uveal melanomas. Compared with 125I, computerized dosimetry suggests a more favorable dose distribution with 103Pd. Treatment of most patients resulted in tumor shrinkage and preservation of functional vision. The authors have noted no complications that might preclude the use of 103Pd ophthalmic plaque radiotherapy for choroidal melanoma.

Ophthalmic plaque radiotherapy for age-related macular degeneration associated with subretinal neovascularization.

PURPOSE: To evaluate ophthalmic plaque radiotherapy for the treatment of subretinal neovascularization associated with age-related macular degeneration. METHODS: In a prospective phase I clinical trial, we treated 23 patients (23 eyes) with ophthalmic plaque radiotherapy for subfoveal exudative macular degeneration. Palladium 103 ophthalmic plaque brachytherapy was delivered to a retinal apex dose of 1,250 to 2,362 cGy (rad). Early Treatment Diabetic Retinopathy Study type visual acuity determinations, ophthalmic examinations, and angiography were performed before and after treatment. Clinical evaluations were performed in a nonrandomized and unmasked fashion. RESULTS: Patients were followed up for a mean (+/-SD) of 19 +/- 10.7 months (range, 3 to 37 months). Six months after radiation therapy, three (16%) of 19 eyes had lost 3 or more lines of best-corrected visual acuity; 12 months after radiation therapy, four eyes (31% of 13 eyes), and 24 months after radiation therapy, only two (22% of nine eyes) lost 3 or more lines of visual acuity. No eye suffered sudden irreversible loss of central vision. No radiation retinopathy, optic neuropathy, or cataract could be attributed to radiotherapy within this follow-up period. CONCLUSION: Ophthalmic plaque radiotherapy can be used to treat neovascular age-related macular degeneration. In contrast to external beam radiotherapy, ophthalmic plaque radiotherapy is a unilateral treatment, which allows a larger dose to be delivered to the macula with less irradiation of normal ocular structures. We have found no sight-limiting complications at the doses, dose rates, and follow-up evaluated in this study.

Plaque-mounted diode-light transillumination for localization around intraocular tumors.

OBJECTIVE: To evaluate the usefulness of plaque-mounted diode-light transillumination (DLT) for the localization of episcleral plaques around intraocular tumors. METHODS: A clinical case series was performed to create, evaluate, and modify diode-light plaque construction, application, and imaging. Eight patients with choroidal melanoma were offered DLT as an additional method of ophthalmic plaque localization. Plaques were constructed by affixing non-heat-producing, light-emitting diodes with their apertures flush with the episcleral outer surface of the rim of the plaque. A bioimplantable epoxy was used to encapsulate the electronic components. Radioactive DLT eye plaques were sewn to the episclera to cover the base of the intraocular tumors; then diode lights were illuminated, viewed, and recorded. Thus, DLT was used to photographically document the relative position of the eye plaque covering the tumor base. The use of DLT also permitted a subjective evaluation of the contact (plaque contact) of each light with the sclera. RESULTS: Still and video images of plaque-mounted diode retro-transillumination were obtained, and no evidence of toxic effects of diode light were noted. CONCLUSIONS: Small posterior melanomas are difficult to visualize with standard transillumination techniques and are associated with poor local control. To improve and document plaque placement, we developed plaque-mounted diode lights for retrobulbar transillumination. This technique provides unique photographic documentation of episcleral plaque localization beneath intraocular tumors.

Seed localization in eye plaque brachytherapy.

We describe a simple method for localizing seeds in eye plaques used for brachytherapy treatment of intraocular tumors and age-related macular degeneration. The method is based on obtaining magnified photocopy images of plaques with seeds in place and then using simple geometrical considerations to reconstruct seed coordinates with about 2% accuracy. A spreadsheet program is used for reconstruction and dosimetric calculations.

Lens epithelium and radiation cataract. I. Preliminary studies.

The migration of epithelial cells during fibergenesis in the lenses of young rats was determined by tritiated thymidine autoradiography. Cells initially labeled in the germinative zone appeared in the lens bow within seven days. Irradiation with either 600 or 2,400 rads of x-rays did not greatly alter the migration rate, but it did interfere with normal differentiation and proper fiber deposition, as manifested by a displacement posteriorly of the lens bow nuclei and an accumulation of abnormal nucleated fibers in the posterior part of the cortex. The presence of labeled cells in those regions prior to the onset of opacification is consistent with the possibility of direct epithelial cell involvement in radiation cataractogenesis.