Techniques for intraoperative hyperthermia with ultrasound: the Dartmouth experience with 19 patients

Abstract

Over the course of 3 years, tumours of 19 patients were heated with ultrasound in the operating room during surgical resection. Immediately following intraoperative radiation therapy, thermocouples were inserted into tumour and adjacent normal structures. Patients were then given a 60-min heat treatment with ultrasound after a 10-15-min heatup period. Temperatures were measured at a total of 133 fixed locations for the 19 patient series. Temperature mapping was done in the tumour volume when logistically feasible. Treatment sites included colorectal (n = 3), portahepatus (n = 1), pancreas (n = 7), liver (n = 1), pelvis (n = 3), sacrum (n = 2), and abdomen (n = 2). A sterile, constant-volume water circulating system was utilized to control surface temperatures. Three generations of completely immersible transducers were designed over the course of this study with a 4-cm height specification. Since the ultrasound transducer was assembled on the sterile field during surgery, a 1, 2 or 3 MHz ceramic element was placed in either a 6, 8 or 10 cm diameter aluminium housing to conform the acoustic field to the tumour size. Average of the maximum temperatures attained was 46.6 degrees C. Temperature with which 90% of all measured points equalled or exceeded (T90) was 39.2 degrees C. The T50 was 42.9 degrees C. This compared favourably with T90 and T50 of 38.8 and 41.9 degrees C, respectively, in our outpatient clinic series, in which superficial tumours were treated with a similar external applicator, and patient tolerance was often a treatment limitation.

Intraoperative hyperthermia in conjunction with multi-schedule chemotherapy (pre-, intra- and post-operative), by-pass surgery, and post-operative radiotherapy for the management of unresectable pancreatic adenocarcinoma

“…Ashayeri et al 18 reported a post-operative survivorship averaged up to 15.8 months for ®ve patients with unresectable pancreatic adenocarcinoma that were treated with simultaneous intra-operative radiotherapy and intra-operativ e hyperthermia. Ryan et al 17 studied 19 patients that were heated with ultrasound in the operating room during surgical resection. Immediately following intra-operativ e radiation therapy, thermocouples were inserted into the tumour and adjacent normal structures.…”

“…Local IOHT has already been used, with quite promising results, without systemic toxicity [16][17][18] . Attempting to improve local control and patient's quality of life, one applied a new treatment modality using the combination of a single session local IOHT with intra-operative (intra-arterial ) chemotherapy.…”

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“…However, regardless of the surgical procedure, the radiation therapy technique, the type of chemotherapy and hormonal therapy, or the combinations thereof, the survival of pancreatic cancer patients remains low, with the major problem that of the local control of disease 10. Local intraoperative hyperthermia (IOHT) has already been used, with promising results, without systemic toxicity …”

Intraoperative hyperthermia and chemoradiotherapy for inoperable pancreatic carcinoma

“…Local intraoperative hyperthermia (IOHT) has been already used with quite promising results without systemic toxicity (Colacchio et al. 1990; Ryan et al. 1992; Ashayeri et al.…”

“…Local intraoperative hyperthermia (IOHT) has been already used with quite promising results without systemic toxicity (Colacchio et al 1990;Ryan et al 1992;Ashayeri et al 1993). The concept of combining hyperthermia with chemotherapy for pancreatic tumours was based on the well-known cell-killing properties of hyperthermia and on its synergistic effects with many chemotherapeutic drugs.…”