Quantitative analysis of effect of neodymium-YAG laser on transplanted mouse carcinomas.

Abstract

ABSTRACr Intradermally transplanted non-immunogenic murine carcinomas measuring 3-6 mm in diameter were exposed to a neodymium-YAG laser beam (1060 nm) over a range of exposure times (0.5-6 seconds) and energy densities (expressed as watts/mm2 exposure field). Subsequent growth of the irradiated tumours was compared with that of untreated tumours. A clear doseresponse relationship dependent only on power delivered per unit area was found. Below a given dose threshold (about 2 joules/mm2) the tumours continued to grow at the same rate as the control tumours although an effect of irradiation could be seen histologically. Above this threshold the tumours completely disappeared but by 10-14 days started to regrow at a rate slightly greater than in 'the control mice; the reason for this increased rate-remains to be determined. At the highest doses (above about 5-5 joules/mm2) there was complete regression and skin healing, with no evidence of local recurrence in seven animals and with no evidence of distant metastases in six out of seven up to 12 months later, a result not previously achieved by surgical excision. The laser provides a controlled and simply applied method of tumour eradication. This animal model gives a quantitative basis for further studies of the effects of laser irradiation on tumour growth.

Current use of lasers in pulmonary disease

“…Some very interesting results have been reported in animal studies by Gardner et al [14] on the dose response characteristics of Nd YAG photoradiation. A transplantable mouse breast adenocarcinoma (WHT adenocarcinoma N-C) injected into the skin of WHT/Ht mice was used as a tumor model, and subjected to a single dose of Nd YAG photoirradiation.…”

“…Small bronchial tumors might, however, be effectively sterilized by Nd YAG photoirradiation in the future and further research may lead to a better understanding of the relevant factors in thermal destruction of tumors by lasers. It has, for example, been suggested that slow heating with low-power irradiation over longer periods may be more effective [15], but this view is not supported by the work of Gardner et al [14].…”

Historical Perspectives on Exotic Pests and Diseases in California

“…Viala suspected that a parasite might be at fault. 21 When Anaheim disease appeared in the San Gabriel area in 1888, the Board of Viticultural Commissioners, at the urging of one of its prominent members, J. De Barth Shorb, hired a «Microscopist and Botanist», Professor Ethelbert Dowlen.…”

Phototherapy of tumors

“…There is some evidence that this might happen in practice. Gardner et al [7] showed that solid mouse tumors, treated with a sublethal dose of light from a Nd YAG laser, regrew from the edges at a slightly faster rate than controls.…”