Beta radiation after pterygium excision скачать в хорошем качестве

Beta radiation after pterygium excision

Radioactivity was discovered in 1896 by Henri Becquerel in uranium. In 1899, Ernest Rutherford separated radioactive emissions into two types: alpha and beta (now beta minus), based on penetration of objects and ability to cause ionization. Alpha rays could be stopped by thin sheets of paper or aluminium, whereas beta rays could penetrate several millimetres of aluminium. In 1900, Paul Villard identified a still more penetrating type of radiation, which Rutherford identified as a fundamentally new type in 1903 and termed gamma rays. Source of Beta irradiation: Strontium 90 (Uranium+Plutonium ) Mechanism of Action: Irradiated cells exhibited either a temporary inhibition of metabolic activity, or a complete and permanent disintegration. Inhibition of growth of conjunctival fibroblasts which reduce fibrosis and recurrence rate. Range of radiation: 3 mm - 1 cm in water. Radiation dose rate is attenuated by 50% after 1.5 mm penetration in water. Half life of Source of irradiation: The source remain clinically useful for at least 20 years. Recalculation of the dose rate is required periodically as the activity of the emitter slowly decays. Dose of radiation in Pterygium: 1000 cGy (rad) in 20 seconds. 3 sessions one minute each , Start in the same day of pterygium excision. Then 1st day and 2nd day postoperative Post operative care: Eye pad for one week, Frequent lubricants . Topical Antibiotic ointment three times/day for one week Side effects of radiation: Conjunctival telangiectasia , Scleral thinning, necrosis and melting. Lens opacity Uses of Beta radiation in Ophthalmology: 1. Adjuvant after pterygium excision, reduce the recurrence rate 2. Treatment of Resistant Vernal conjunctivitis (Palpebral Spring Catarrh) 3. Treatment of corneal vascularisation 4. Adjuvant to Sub Scleral trabeculectomy 5. Treatment of ocular surface superficial neoplasia 6. Treatment of benign eyelid neoplasia 7. Treatment of pyogenic granuloma 8. Treatment of Wet Age-related macular degeneration (not the same probe)