A physiologic and anatomic study after pulmonary irradiation in dogs. A 52 week report.

Physiologic and anatomic changes following unilateral pubnonary irradiation up to 6,000 rads in dogs were studied. Fractionate irradiation was given to the right lung of 11 dogs divided into three groups which received 2,000, 4,000 and 6,000 rads respectively. Differential bronchospirometry was serially performed at approximately four week intervals for one year. There was no signfficant change in the relative distribution of ventilation and oxygen uptake between the irradiated and the confralateral control lungs. Upon diversion of the entire cardiac output through the irradiated lung by temporary unilateral pulmonary artery occlusion, pulmonary artery pressure and left afrmal pressure remained within normal limits. Thus, there was no suggestion of increased pulmonary vascular resistance as a consequence of irradiation. Neither adhesions nor abnormalities of the bronchial vessels were observed. The microscopic findings consisted of focal organized pneumonia which was found only in the 4,000 and 6,000 rads groups, and mild focal interstitial