New approach of controlling the area affected in brain tumour treatment by LITT

There are some techniques to ablate tumours of brain, breast and liver. One of them is laser irradiation. The most important problem of this technique is to injure noncancerous tissues. It is a challenging work to control the domain of laser effects. In other words, it is hard to ablate cancerous tissue without ablating noncancerous. To gain this goal, some researchers have been proposed some ways, such as using two or three applicators or moving applicator. The objective of this paper is to present an approach to control the temperature distribution and heat affected zone in brain tumours when irradiated by shielded laser beam, 1064 nm ND-YAG. The effects of laser beam, resulting in tissue temperature increasing, follows the border of tumour by defining of a dual intensity distribution. This is included two distinct intensity distributions of laser on the applicator by shielding. Treatment of an arbitrary topology of tumour will be simulated irradiation of laser by two different distributions through numerical method. Results show when dual distribution on the tumour border is used, the pattern of photon distribution is coincident by the tumour and the affected zone and temperature increasing follows the borderline of tumour, qualitatively. It shows that the ablated volume of tumour will be 53% more than when the unique distribution is used and the treatment time is shorter, resultantly.