An interstitial light assembly for photodynamic therapy in prostatic carcinoma.
Lee, L K Whitehurst, Colin Pantelides, M L Moore, James V
Lee, L K
Whitehurst, Colin
Pantelides, M L
Moore, James V
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Abstract
OBJECTIVE: To develop an interstitial laser light delivery system using multiple optical fibres for photodynamic therapy (PDT) in the treatment of prostate cancer. PATIENTS AND METHODS: A laser beam was divided equally with a 1 x 4 fibre splitter to deliver PDT simultaneously through four 2-cm long, flexible cylindrical optical diffusers. Biplanar transrectal ultrasonography (TRUS) and a template were used to position the optical fibres percutaneously. In vivo measurements of light penetration depth (1/micro[eff] ) in prostate tissue were made in seven patients, using a sheathed isoprobe to measure light fluence rates at varying radial distances from the diffuser. The prostate was fixed with stabilization needles to minimize displacement during needle placement. RESULTS: The mean (sd, range) micro(eff) in the prostates of the seven patients was 0.35 (0.07, 0.22-0.44) mm-1, which produced closely parallel slopes of light attenuation. However, there was up to a 10-fold variation in absolute light levels at the same diffuser-detector separation distances amongst the seven patients, probably caused by blood pooling around the diffuser light source. A similar problem around the isoprobe detector was overcome by sheathing the probe in clear plastic tubing. By stabilizing the prostate, the optical fibre positioning was precise to within 2 mm. CONCLUSION: Although this light delivery and TRUS assembly were developed for clinical PDT in the prostate, the same instrumentation can be used reliably for in vivo light-penetration studies. Haemorrhage was unpredictable and highlighted one of the main problems which needs to be overcome.
Description
Date
1999-11
Publisher
Collections
Keywords
Prostatic Cancer
Type
Article
Citation
An interstitial light assembly for photodynamic therapy in prostatic carcinoma. 1999, 84 (7):821-6 BJU Int.