In this analysis, the use of Fx greater than 2.67 Gy was the most significant factor associated with an increased risk of RP. High total dose also appears to be associated with an increased risk, but twice-daily irradiation seems to reduce the risk expected if the same total daily dose is given as a single fraction. High-Fx radiotherapy should be avoided in patients who receive CMT with curative intent.

Nine patients with ocular lymphomas were seen in the Department of Ophthalmology and the Division of Radiation Oncology at UCSF and Ralph K. Davies Medical Center, San Francisco, from 1978 through 1974. Six of the 9 patients had visual symptoms as the first manifestation of their disease. Eight of the 9 patients developed intracranial lymphoma at some time during the course of the disease. Despite lymphoma work‐up including bone marrow biopsies and lymphangiogram, only 1 patient was found to have documented systemic involvement. The diagnosis of ocular lymphoma was based on pathologic material from the eye in 5 cases or from central nervous system biopsy in 4 patients in association with tumor cell infiltrates in the retina and vitreous clouding. Radiation therapy to the eyes improved vision in 10 of 13 eyes treated in 8 patients. The usual dose was in the range of 3500 to 4500 rads given over 4–5 weeks. In addition, 7 patients received central nervous system irradiation. Review of the literature reinforced the findings of this series showing the frequent association of ocular lymphoma with intracranial lymphoma and the rare systemic dissemination. This disease process has previously been referred to as ocular reticulum cell sarcoma. Cancer 45:688‐692, 1980.

The effects of several cancer chemotherapeutic agents on radiation damage to normal intestine, esophagus, and lung tissue were evaluated in LAF, mice using quantitive endpoints. In all tissues tested, actinomycin D increased injury and BCNU did not. In the intestine, adriamycin enhanced radiation damage more than any other agent. Bleomycin increased damage in the esophagus but not in the lung or intestine. Cyclophosphamide increased injury only in the lung, where vincristine caused minimal injury, and hydroxyurea, none. Only prednisolone caused significant radioprotection when given at the time of irradiation or at the time of expected death from pulmonary injury. ." T h e pulmonary toxicity observed with bleomycin' has led to fears that this agent might increase radiation pneumonitis. Because of the clinical and experimental evidence that some drugs increase the injury to an irradiated tissue, either through additivity of cell killing or through increasing cell killing per rad (sensitization), it is necessary to explore the degree to which cancer chemotherapeutic agents affect the radiation response of certain critical tissues. T h e experiments reported here were designed to determine the degree of injury occurring in the intestine, the esophagus, and the lung with a number of cancer chemotherapeutic agents in widespread clinical use.Because of reports that prednisolone may reduce radiation injury in t h e lung, it was also studied. MATERIALS AND METHODS.4ll experiments reported here were carried out in 12-week-old LAF, male mice (Jackson Laboratories, Bar Harbor, ME). T h e mice, housed live per cage, were allowed to adjust to our animal quarters for at least 2 weeks before use, a n d were m a i n t a i n e d on s t a n d a r d laboratory chow and water a d libitum.For intestinal microcolony experiments, the mice were exposed to whole body radiation in a 2000-Ci, '37Cs irradiator at a dose rate of 275 rads/minute in rotating lucite cages. For esophageal and pulmonary experiments, irradiation was carried out with orthovoltage x rays from a 300-kVp generator. H V L 1.6 m m Cu, dose rate 330 rads/minute. Dosimetry was checked with T L D dosimeters. Before irradiation, the head and body of each mouse were shielded with lead, 6 m m thick, exposing a 2.5-cm strip of the thorax from the thoracic inlet to the lower limits of the anterior thoracic cage. For the esophageal lethality endpoint, mice were i r r a d i a t e d while b r e a t h i n g a i r ; for t h e pulmonary endpoint, mice were irradiated while breathing 5.5% oxygen in nitrogen.Techniques for measuring injury in the int e~t i n e , '~ esophagus, l 6 3 l 7 and have all been described elsewhere. Briefly, these were as follows : For the intestinal microcolony endpoint, mice were sacrificed 3 '/2 days after irradiation, and the entire jejunum was removed. It was fixed in toto a n d then sectioned into eight separate 1-cm samples, which were embedded on end side by side in a paraffin 1678

A series of 51 patients treated with 92 separate lung fields for metastatic pulmonary disease between 1958 and 1971 is reviewed. The treatment data are converted into nominal single doses (NSD) and a newly derived formula for estimated single doses (ED). The 5% incidence level of pneumonitis without dactinomycin is 770 rets (NSD) and 510 rets (ED) and with dactinomycin, 520 rets (NSD) and 450 rets (ED). A safe treatment regimen for avoiding radiation pneumonitis is 1500 rads in 10 fractions with dactinomycin and 2500 rads in 20 fractions without dactinomycin.