A multicentre randomized/controlled trial of a conventional versus modestly accelerated radiotherapy in the laryngeal cancer: influence of a 1 week shortening overall time.

BACKGROUND AND PURPOSE: To compare in a phase III study the loco-regional control, disease-free survival and overall survival induced by an accelerated regimen (AF) as compared with conventional regimen (CF) and to analyze the early and late post-radiation morbidity in both arms. MATERIALS AND METHODS: Patients with age < or = 75, WHO 0-1, suitable for a radical course of radiotherapy T1-T3, N0, M0, stage of glottic and supraglottic laryngeal cancer were randomized to either CF: 66Gy given in 33 fractions over 45 days or AF: 66Gy given in 33 fractions over 38 days (2 fractions every Thursday). A total of 395 patients were included from 05.1995 to 12.1998. RESULTS: Early toxicity: At the end of radiotherapy patients treated with AF complained for more severe reactions than patients treated with CF. In 8 weeks after treatment completion patients treated with AF complained only for more severe pain on swallowing (P=0.027). In 4 months after treatment completion all types of toxicity except for skin teleangiectasia (P=0.001) were similar in the two groups. Loco-regional control: comparison between CF and AF showed no difference in terms of loco-regional control (P=0.37). CONCLUSIONS: The improvement in AF in terms of loco-regional control is estimated to be 3-5% in comparison with conventional regimen and is not significant. The intensity of reactions after 4 months was similar in both arms, what suggests the possibility of further shortening of the overall time by few days or enhancing the total dose within the limits of acceptable morbidity.

Dose-rate distribution in wedged beams of 9 MV X-rays from Linac Neptune 10p and of gamma-ray beams from Gammatron 80S.

The method of calculation of the two- and three-dimensional dose-rate distribution for wedged beams of 9 MV X-rays and Co-60 gamma-rays is presented. The method was examined for Linac Neptune 10p and Gammatron 80S. The experimental results show that for computing the dose-rate distribution of a wedged beam it is sufficient to know: 1. the profile function for open fields defined as the relative dose-rate distribution across the radiation beam and 2. the parameters of the wedge filter. The computed and measured results are presented in tables and on graphs.

Three-dimensional dose-rate distribution of X-ray beams of linac neptun 10p and gamma-rays from Co-60 gammatron 80S for rectangular fields.

A method of calculation of the three-dimensional dose-rate distribution for X-rays of Linac Neptun 10p and gamma-rays of Gamma-tron 80S is presented. The experimental results show that the profiles function defined as the relative dose-rate across the radiation beam is useful for this purpose, and it is sufficient to determine the profile function only at one depth and for one field size. The results of measurements are presented on the graphs.