Abstract
Red light (c. 630 nm) is almost universally used in tumour phototherapy as it is the most penetrating of the porphyrin excitation wavebands. However, measurements of tumour attenuation of light of different wavelengths and of the excitation spectrum of haematoporphyrin derivative in vitro suggested that green light might be more efficient than red in destroying thin tumours. Experimentally, we confirmed this for tumours up to approximately 1.2 mm thick, a depth exceeding that of most carcinomas-in-situ. The superiority of green light over red in terms of the illumination time required to produce equivalent depths of necrosis may extend to greater depths (3-4 mm) if the former is produced by an argon laser and the latter by an argon-pumped dye laser. The relation between depth of necrosis Zn and light dose D is shown to be Zn = sigma gamma-1 1n(D/theta gamma) where sigma gamma is the attenuation coefficient for light at wavelength gamma and theta gamma the threshold light dose for producing necrosis at that wavelength. This logarithmic relationship suggests that it may be difficult to eradicate large tumours merely by increasing the light dose, and indicates the need for other approaches.
Full text
PDF
Images in this article
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Anderson R. R., Parrish J. A. The optics of human skin. J Invest Dermatol. 1981 Jul;77(1):13–19. doi: 10.1111/1523-1747.ep12479191. [DOI] [PubMed] [Google Scholar]
- Benson R. C., Jr, Kinsey J. H., Cortese D. A., Farrow G. M., Utz D. C. Treatment of transitional cell carcinoma of the bladder with hematoporphyrin derivative phototherapy. J Urol. 1983 Dec;130(6):1090–1095. doi: 10.1016/s0022-5347(17)51699-7. [DOI] [PubMed] [Google Scholar]
- Berenbaum M. C., Bonnett R., Scourides P. A. In vivo biological activity of the components of haematoporphyrin derivative. Br J Cancer. 1982 Apr;45(4):571–581. doi: 10.1038/bjc.1982.94. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Dougherty T. J., Gomer C. J., Weishaupt K. R. Energetics and efficiency of photoinactivation of murine tumor cells containing hematoporphyrin. Cancer Res. 1976 Jul;36(7 Pt 1):2330–2333. [PubMed] [Google Scholar]
- Eichler J., Knof J., Lenz H. Measurements on the depth of penetration of light (0.35--1.0 microgram) in tissue. Radiat Environ Biophys. 1977 Oct 12;14(3):239–242. doi: 10.1007/BF01323942. [DOI] [PubMed] [Google Scholar]
- Langelaar J., de Vries G. A., Bebelaar D. Sensitivity improvements in spectrophospho-fluorimetry. J Sci Instrum. 1969 Feb;2(2):149–152. doi: 10.1088/0022-3735/2/2/306. [DOI] [PubMed] [Google Scholar]
- Reinhold H. S. Quantitative evaluation of the radiosensitivity of cells of a transplantable rhabdomyosarcoma in the rat. Eur J Cancer. 1966 Feb;2(1):33–42. doi: 10.1016/0014-2964(66)90087-9. [DOI] [PubMed] [Google Scholar]
- Tsuchiya A., Obara N., Miwa M., Ohi T., Kato H., Hayata Y. Hematoporphyrin derivative and laser photoradiation in the diagnosis and treatment of bladder cancer. J Urol. 1983 Jul;130(1):79–82. doi: 10.1016/s0022-5347(17)50965-9. [DOI] [PubMed] [Google Scholar]
- van Gemert M. J., Henning J. P. A model approach to laser coagulation of dermal vascular lesions. Arch Dermatol Res. 1981;270(4):429–439. doi: 10.1007/BF00403787. [DOI] [PubMed] [Google Scholar]