Trackless surgery using focused ultrasound: Technique and case report

SummaryHigh intensity ultrasound may be focused within tissue to produce ‘trackless’ lesions, that is, to destroy selected tissue volumes without damage to structures lying between the source of the sound beam (the transducer) and the target volume. This physical property provides the potential for the use of ultrasound in a non-invasive ‘surgical’ technique for the destruction of tissues lying at depth within the human body.In this paper, the design of equipment to carry out such focused beam surgery is described, and its use in a case study involving a cat with metastatic melanoma of the liver is outlined. A closely defined region of liver measuring 4 × 2.5 × 2.5 cm was successfully treated, post-mortem histology showing no viable cells remaining in that volume.Although the technique as described here was designed for the treatment of discrete liver metastases, focused beam surgery may have wider applications in, for example, benign prostate hyperplasia or urological tumours.