LIVER-TISSUE DAMAGE BY ULTRASOUND IN COMBINATION WITH THE PHOTOSENSITIZING DRUG, PHOTOFRIN-II

We have investigated whether ablation of normal rat liver by ultrasoun d can be enhanced after administration of a photosensitizing agent (Ph otofrin II). After laparotomy and administration of Photofrin II (30 m g/kg), ultrasound (210 kHz, 1.3 W/cm(2)) was directed directly to the surface of the liver for a total duration of 3 min by a plane type unf ocused transducer (6 mm x 6 mm). The depth of tissue damage was histol ogically compared to rats exposed to ultrasound alone. The mean maximu m lesion depth on rats applied with ultrasound and Photofrin II was 5. 7 +/- 0.9 mm (mean +/- SD) whereas in rats treated with ultrasound alo ne this was 3.0 +/- 0.4 mm. There was a significant difference between the two groups (P < 0.05). The present study suggests the possible us e of a photosensitizing agent as an enhancer for the treatment of live r tumors by ultrasound.