The clinical applications of high intensity focused ultrasound in the prostate

Figures & data

Box 1 Desireable attributes of a new tissue ablation technology for prostate cancer (from Gillett et al. [9]).

• Administered with the patient under local anaesthesia

• Real time monitoring of treatment

• Excellent oncological efficacy (destruction of all prostate cancer)

• Minimal inflammatory response

• No adverse effect on pre-treatment erectile function

• No adverse effect on pre-treatment urinary continence

• No injury to adjacent structures (rectum, bladder)

• Repeatable

• Low cost

• Outpatient treatment

Figure 1. The Ablatherm® therapy platform demonstrating the probe integrated into treatment bed (console not shown) (Courtesy of EDAP-TMS).

Figure 2. The Sonablate®500 mobile console, articulated Probe Arm, Probe, and Sonachill™ cooling unit (Courtesy of Focus Surgery, Inc.).

Table I.  Similarities and differences between the Sonablate®500 and Ablatherm® systems.

	Differences
Similarities	Sonablate®	Ablatherm®
Units consist of user interface, ultrasound generator, imaging system, chiller and trans-rectal probe	User may vary input power manually depending upon the visual changes seen during treatment	Pre-defined power levels depending upon primary, salvage or repeat HIFU treatments
Trans-rectal probe enclosed in a sheath	Lithotomy treatment position on standard operating table	Right lateral decubitus treatment position on integrated table
May be administered under spinal/epidural or general anaesthetic	Recommended use without prior procedure to the prostate	Recommended use immediately following ‘mini’ trans-urethral resection of the prostate/Bladder neck Incision
Real time prostate imaging	Multiple transducers of different focal lengths housed within single probe tip. Each transducer driven at 4 MHz and used for planning and therapy	Single, multifrequency probe tip. 7.5 MHz transducer for planning set confocally within a 3 MHz treatment transducer
User input to delineate the prostate boundaries	Smaller volume treated in each acoustic exposure, necessitating treatment in three ‘blocks’ being planned–anterior, middle and posterior	Larger volume treated in each acoustic exposure, antero-posterior dimension of the prostate covered in single exposure
Fluid circulated around probe tip to cool both rectal wall and transducer
Mechanism of prostate ablation both thermal and mechanical
Procedure time around 3 hours in total
Real-time rectal wall distance monitoring
CE approved in Europe
FDA trials underway in the USA

Gillett MD, Gettman MT, Zincke H, Blute ML. Tissue ablation technologies for localised prostate cancer. Mayo Clin Proc 2004; 79: 1547–1555

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