The Effects of Chest Irradiation on Pulmonary Function*†

Abstract

Pathological changes in lung tissue following chest wall irradiation have been adequately documented in the past (1-5). However, pulmonary function has not been systematically studied. Published studies (6-9) are incomplete and the findings complicated by the original disease. In view of this and because of a desire to determine the amount of radiation which might safely be administered to the chest, a systematic study was undertaken in dogs. The results of this study follow. METHODSPulmonary function and vascular resistance were evaluated in dogs before and after irradiation to the chest. All studies were performed under pentobarbital anesthesia. Two different irradiation schedules were utilized. Eight dogs received a calculated dose of 1,000 to 2,900 roentgens (r) to the mid-chest in a single exposure. No animal survived longer than two and one-half months. For practical reasons, it was not feasible to study resistance and function in the same animal. Therefore, resistance was evaluated in the first five animals within 24 hours of irradiation. Diffusing capacity, functional residual volume and compliance were determined in the remaining three animals at two to three week intervals. In order to effect a longer period of survival, seven animals were irradiated under a second schedule consisting of a dosage of 200 to 300 r to each side of the chest repeated at weekly intervals up to a total calculated mid-chest dose of 3,000 to 4,800 r. Three of these animals survived longer than six months. Diffusing capacity, functional residual volume and compliance were determined at two to three month intervals following onset of irradiation. Vascular studies were also conducted in four animals at the time of the final evaluation. 4 Clinical Investigator of the Veterans Administration.All irradiation was given with 260 KV. peak equipment (filter, one-half mm. Cu, 1 mm. Al, half-value layer 1 mm. Cu; target-skin distance, 50 to 70 cm.) with the animals under pentobarbital anesthesia. Field size included the chest from xiphoid to lower neck.Compliance. Values for total thorax, lung and chest wall compliance were obtained by the static method (10) with the animals anesthetized and curarized. A cardiac catheter, with a latex condom secured to the terminal 5 inches, was introduced well into the thoracic portion of the esophagus (11, 12). The catheter was marked at the level opposite the incisors, so that it could be placed in the same position in subsequent tests. A cuffed endotracheal tube was positioned within the trachea and sealed by inflation of the cuff. Muscle paralysis was obtained by the intravenous injection of approximately 6 ml. of a 0.01 per cent solution of succinyl-choline. Respiration was maintained artificially with a mechanical respirator, except during evaluation of the pressure-volume relationships. Air was introduced into the tracheal cannula until pressure in the cannula reached a pre-selected level. In order to minimize variations due to hysteresis, inflation time for a given volume was maintained approxima...

Inhaled /sup 239/PuO/sub 2/ and/or total-body gamma radiation: Early mortality and morbidity in rats and dogs

“…Functional residual capacity (FRC), DLco, and CL were found to decrease progressively after 3000 to 4800 R of 260-kVp X-ray exposure, given in increments of 200 to 300 Rheek. The most obvious changes occurred approximately 3 months after exposure (Sweany et al, 1959).…”

Inhaled /sup 147/Pm and/or total-body gamma radiation: Early mortality and morbidity in rats

“…Functional residual capacity (FRC), DLco, and CL were found to decrease progressively after 3000 to 4800 R of 260-kVp X-ray exposure, given in increments of 200 t o 300 R/week. The most obvious changes occurred approximately 3 months after exposure (Sweany et al, 1959). In another study, dogs received unilateral, thoracic, 200-kVp X-irradiation (4500 R over 23 to 27 days), and pulmonary function was tested in each lung of each dog.…”

Repercussões tardias da radioterapia sobre a função pulmonar em pacientes com câncer de mama

“…Com a radiação, ocorre uma indução no processo de diferenciação dos fibroblastos seguida de aumento da síntese de colágeno intersticial (RODEMANN;BAMBERG, 1995), espessamento da parede vascular e conseqüente diminuição da complacência. A complacência também pode encontrar-se alterada na presença de cicatriz aderente à parede torácica determinada pela cirurgia e radioterapia, porém, na maioria das vezes, a queda da complacência após a radiação é ocasionada por alterações pulmonares e não por afecções torácicas (SWEANY;MOSS;HADDY, 1959;SHRIVASTAVA;HANS;CONCANNON, 1974).…”