Effects of fast neutrons on the eye.

Abstract

This report describes the ophthalmic examination of patients receiving MeV fast neutrons for the treatment of advanced tumours of the head in which the eye was unavoidably irradiated. The treatment was given by the Medical Research Council's cyclotron, and details have been published (Catterall and Vonberg, I974;Catterall, Sutherland, and Bewley, 1975). A preliminary report on the effects of neutron irradiation on the eye has also been completed (Brown, Roth, Catterall, and Beal, 1976 Ophthalmic examinationThe symptoms and signs found on ophthalmic examination were scored in intensity on a scale of 0 to 4. The eye was examined in detail and observations quantified for analysis. Colour macrophotography was used to record superficial signs and slit-image photography to record the lens of the eye (Brown, I972). The patients were examined before treatment when possible and thereafter at first weekly, then monthly, and later at longer intervals. ResultsThe length of follow-up was not enough to include all possible late complications but we consider Address for reprints: N. Brown,

Radiotherapy-Induced Ocular Surface Disease

“…20 The structural changes of the eyelids may lead to ectropion or entropion, atrophy and thinning of the tarsus, rounding of the posterior lid margin with keratinization, and finally lid notching from loss of tissue. 21 Functionally, these changes impact both the ability of the eyelid to adequately cover the epibulbar surface as well as retaining a smooth and stable protective film leading to a profound compromise in eyelid function with consequent devastating effects on the ocular surface.…”

Ultrastructural Retinal Changes after Irradiation with Fast Neutrons

“…Depending on the type of radia tion and the mode of fractionation threshold values, round about 2,000 cGy have been reported in the literature as causing retinal damage [5][6][7][8][9]12]. Ultrastructural alterations of the rods of guinea pig retina were first described after exposure to a single X-ray dose of 1,500 cGy [1], The only paper pre sented so far on the effect of fast neutrons on the eye, which was observed as a side effect in patients who had tumours in the vicinity of the eye and had been irradiated in the head and neck regions, fails to give any threshold values [14], Due to their higher biological effectiveness, fast neutrons cause retinal damage much earlier than do conven tional types of radiation [3].…”

“…Fast neutrons are not suitable for the treatment of eye tumours because of their beam geometry [2], But depending on the location of the tumour to be irradiated the intact eye could be exposed to radiation haz ards [4,14],…”

Ionizing radiation risks to satellite power systems (SPS) workers

“…In radio therapy patients exposed to 14-MeV cyclotron neutrons, m change in the lens was seen following 80 rad in 12 fractions. However, slight permanent vision loss was found after 220 rad (Roth et al, 1976). Despite a knowledge of the neutron dose in the Japanese atomic bomD survivors, the neutron dose effect on the induction of cataracts is not Known.…”