strontium-radioisotopes and Cataract

A retrospective study was done of 338 patients with pterygia treated between October 1974 and May 1990. These patients resided in the desert of the southwestern United States, where the hot, dry, dusty climate is thought to predispose to pterygium formation and subsequent recurrence. The pterygia were excised, and the administration of beta irradiation was initiated within 24 hr of surgery. Sixteen percent of the pterygia were recurrent. Ninety-five percent of the beta irradiation prescriptions consisted of 3 weekly 800 cGy fractions. For patients with a minimum of 6 months follow-up, the crude local control rate was 225/258 (88%). The Kaplan-Meier estimate of the 5-year local control rate was 84% (95% confidence interval: 79-89%). Ten of 33 recurrences were diagnosed within 6 months, and 32/33 recurrences were diagnosed within 5 years of treatment. Previously untreated pterygia were controlled more easily than were recurrent pterygia (p = 0.005). In 86% of the cases, patients judged the cosmetic results to be satisfactory. No severe complications developed. This study and others, when compared with studies involving excision alone, suggest that postoperative beta irradiation reduces the likelihood for pterygium recurrence. When the beta irradiation is fractionated, satisfactory cosmetic results can be achieved with low morbidity.

Topics: Adult; Aged; Beta Particles; Cataract; Combined Modality Therapy; Humans; Middle Aged; Pterygium; Radiotherapy Dosage; Recurrence; Strontium Radioisotopes

To study the long-term effects of low-dosage strontium-90 (Sr90) irradiation on the recurrence of pterygium.. One hundred twenty eyes from 104 patients with primary or recurrent pterygia were treated with surgery followed by Sr90 irradiation. In brief, starting on the sixth day after surgery, patients were treated with irradiation three times every other day at a total combined dosage of 2000 cGy to 3000 cGy. Corneal topography was used to evaluate ocular surface regularity before and after treatment. Patient follow-up was performed 2 days, 5 days, 2 weeks, 1 month, 3 months, 1 year, 5 years, and 10 years after surgery. Recurrence of pterygium was not observed in any of the patients in this study. Obvious cataract progression was observed in 6 eyes, which may be due to aging. During follow-up studies, only one eye was reported with dryness and foreign-body sensation. Significant pterygium-induced astigmatism was observed in corneal topography, which decreased after surgery.. Sr90 irradiation is effective in preventing the recurrence of primary and recurrent pterygia. We recommend delivering a total combined dosage of 2000 cGy to 3000 cGy of Sr90 irradiation administered in three batches every other day starting from the sixth day after surgery. Surgery is important in the rapid recovery of the cornea from pterygium-induced astigmatism.

Topics: Adult; Aged; Astigmatism; Cataract; Cornea; Corneal Topography; Humans; Middle Aged; Ophthalmology; Pterygium; Radiotherapy; Recurrence; Strontium Radioisotopes; Time Factors; Treatment Outcome

The results of a study of 975 pterygia treated surgically and immediately with Strontium 90 are presented. The recurrence rate (quiescent) was 6%. The actual recurrence requiring surgery was 0.82%. Technique of removal involves simple wide excision and immediate treatment with Strontium 90 over the entire area. Three thousand RADS is the maximum dosage. In most instances more than 3000 RADS is cataractogenic. Two methods of Strontium 90 production are discussed. Strontium 90 has a half life of 19.9 plus or minus .3 years. It decomposes to Yttrium 90 which has a half life of 62 hours. Tissue penetration is estimated by the use of polystyrene absorber which is considered to be a tissue equivalent. Age and sex occurrence is given from a survey of 832 patients. Newer developments that might replace Strontium 90 are briefly discussed.

Topics: Adult; Age Factors; Brachytherapy; Cataract; Female; Humans; Male; Pterygium; Recurrence; Sex Factors; Strontium Radioisotopes

Topics: Cadaver; Cataract; Environmental Exposure; Eye; Humans; Radiation Dosage; Radiation Injuries; Strontium Radioisotopes