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In situ COMPARISON OF 665 nm and 633 nm WAVELENGTH LIGHT PENETRATION IN THE HUMAN PROSTATE GLAND
Author(s) -
Lee L. K.,
Whitehurst C.,
Pantelides M. L.,
Moore J. V.
Publication year - 1995
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1995.tb09151.x
Subject(s) - photodynamic therapy , photosensitizer , prostate , wavelength , penetration depth , penetration (warfare) , materials science , attenuation , fluence , chemistry , optics , biomedical engineering , medicine , optoelectronics , laser , cancer , photochemistry , physics , organic chemistry , operations research , engineering
— The depth of treatment in photodynamic therapy (PDT) of tumors varies with the wavelength of light activating the photosensitizer. New generation photosensitizers that are excited at longer wavelengths have the potential for increasing treatment depths. Tin ethyl etiopurpurin (SnET2), a promising second‐generation photosensitizer is maximally activated at 665 nm, which may be significantly more penetrating than 633 nm light currently used with porphyrins in PDT. The penetration of 665 nm and 633 nm wavelength red light in the prostate gland was compared in 11 patients undergoing prostatic biopsies for suspected prostatic cancer. Interstitial optical fibers determined the light attenuation within the prostate gland. Of the 11 patients, 7 had dual wavelength and 4 had single wavelength studies. The mean attenuation coefficients, μ eff , for 665 nm and 633 nm wavelength light were 0.32 ± 0.05 mm ‐1 and 0.39 ± 0.05 mm ‐1 , respectively, showing a statistically significant difference (P = 0.0003). This represented a 22% increase in the mean penetration depth and at 10 mm from the delivery fiber there was 1.8 times as much 665 nm light fluence than 633 nm. The mean μ eff at 665 nm for benign and malignant prostate tissue were similar ( P = 0.42), however, there was significant interpatient variation (μ eff ranging from 0.24 to 0.42 mm ‐1 ) reflecting biological differences of therapeutic importance. The enhanced light fluence and penetration depth with 665 nm light should allow significantly larger volumes of prostatic tissue to be treated with SnET2‐mediated PDT.