Premium
An interstitial light assembly for photodynamic therapy in prostatic carcinoma
Author(s) -
Myeong Soo Lee,
Whitehurst,
Pantelides,
Paul S. Moore
Publication year - 1999
Publication title -
bju international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 1464-4096
DOI - 10.1046/j.1464-410x.1999.00314.x
Subject(s) - photodynamic therapy , prostate , biomedical engineering , materials science , laser , diffuser (optics) , medicine , optics , nuclear medicine , light source , cancer , chemistry , physics , organic chemistry
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 1×4 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/μ 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) μ 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.