A PHASE-I AND PHASE-II CLINICAL-TRIAL OF A NEWLY DEVELOPED ULTRASOUNDHYPERTHERMIA SYSTEM WITH AN IMPROVED PLANAR TRANSDUCER

Purpose: The clinical usefulness of a newly developed ultrasound hyper thermia system was evaluated. Methods and Materials: The hyperthermia system uses a modified planer transducer operated at frequencies of 0. 5, 1.0, and 1.5 MHz. The transducer has a nonvibrating part at the cen ter to reduce the central hot spot. Frequency sweeping technique is al so used to eliminate the annular hot spot around the center. Thirty-ei ght tumors in 29 patients were examined in this study. In 35 tumors, h yperthermia was given in conjunction with irradiation and/or chemother apy, and in the remaining 3 tumors, hyperthermia alone was given. In a ll, a total of 153 hyperthermia sessions were performed. Results: The number of hyperthermia sessions per tumor ranged from 1 to 7 (mean, 4. 0 +/- 1.3). The number of intratumor thermometry points per session ra nged from 1 to 8 (mean, 4.3 +/- 1.5). The average intratumor temperatu re for tumors with a maximum depth of <3 cm, 3-6 cm, and >6 cm was 42. 1 +/- 1.2, 41.7 +/- 1.4, and 39.9 +/- 2.0 degrees C, respectively. The percentage of monitored intratumor points with temperature exceeding 42 degrees C was 56 +/- 31%, 43 +/- 34%, and 21 +/- 24%, respectively. Of the 30 evaluable tumors treated with combined irradiation, 12 show ed complete response, 14 partial response, and 4 no change. Observed c omplications included pain at the treatment site in 13 of the 153 trea tment sessions and vesicle formation in 3 of the 38 treatment sites. N o serious complication was seen. Conclusions: These results indicate t hat the newly developed ultrasound hyperthermia system is clinically u seful for the treatment of localized superficial and subsurface tumors with a maximum tumor depth of no more than 6 cm. Copyright (C) 1996 E lsevier Science Inc.