Computed tomographic evaluation of radiation pneumonitis in a canine model

Abstract

The objective of this study was to document the utility of computed tomography (CT) and a three‐dimensional (3‐D) radiotherapy treatment planning system for assessing the development of acute radiation pneumonitis in a canine model. Fourteen dogs were randomly assigned to a nonirradiated control group or one of three radiation dose groups receiving a single fraction of either 12, 15, or 18 Gy delivered to two‐thirds of the right hemithorax. CT and survey radiographs were performed in all dogs prior to and at defined intervals for up to 13 weeks following irradiation. All images were subjectively evaluated for development of radiation pneumonitis and CT images were quantitatively analyzed. Radiation pneumonitis was detected earlier with CT images than with radiographs. Quantitatively, functional lung volume and radiation pneumonitis lesion volume on CT images changed over time in all irradiated dogs. However, there was no statistically significant difference between the three radiation dose groups, but a marked difference between irradiated dogs and nonirradiated controls. These data suggest that CT is superior to survey radiography for the evaluation and quantification of acute radiation pneumonitis in this canine model. Quantification of acute radiation pneumonitis suggests future promise for evaluating the efficacy of modifiers to lessen the effects of irradiating normal lung tissue in this canine model. Radiat. Oncol. Invest. 6:128–134, 1998. © 1998 Wiley‐Liss, Inc.

Consecutive CT-guided core needle tissue biopsy of lung lesions in the same dog at different phases of radiation-induced lung injury

“…No new drugs have been approved by the FDA for the treatment or prevention of RP, and the mortality rate in patients with severe RP is very high. Several important studies [ 20 ] have already shown how to use Beagle dogs to establish a successful radiation-induced lung injury model. For the first time, we reported consecutive CT-guided core needle tissue biopsies of lung lesions in the same dog at different phases of radiation-induced lung injury.…”