A spectral method for magnetohydrodynamic stability

Proton beam irradiation is the treatment modality highly convenient in certain malignancies, especially the tumours located inside or in close vicinity to the radiosensitive organs or structures. Nowadays, it is the treatment of choice in most of the cases of uveal malignant melanoma. Usual problems in surgical treatment and the advantages of the proton beam are emphasized. However, long term follow up studies show important side effects on vulnerable ocular structures in some patients, to this paper, a Monte Carlo simulation of proton beam irradiating of an intraocular melanoma is presented. A simplified geometrical model of a human eye is developed. Three-dimensional distribution of energy deposited in (lie tumour and within the adjacent ocular structures is calculated. Ratio of energy absorbed by the tumour and by surrounding tissues is discussed. (author)