One hundred fifty‐seven patients referred to the Department of Radiation Oncology of the Hǒpital Tenon, Paris, France, between December 10, 1986 and December 31, 1989 for total‐body irradiation (TBI) ...were treated according to the following two techniques: (1) either in one fraction (1000 cGy administered to the midplane at L4 and 800 cGy to the lungs) or (2) in six fractions (1200 cGy on 3 consecutive days to the midplane at L4 and 900 cGy to the lungs). The patients were randomized according to two instantaneous dose rates, called LOW and HIGH, in single‐dose (6 versus 15 cGy/min) and hexafractionated (3 versus 6 cGy/min) TBI groups. There were 77 patients in the LOW group and 80 in the HIGH group, with 57 patients receiving single‐dose TBI (28 LOW and 29 HIGH) and 100 patients receiving fractionated‐dose TBI (49 LOW and 51 HIGH). In March 1991, the 4‐year relapse‐free and overall survival rates were 58.4% and 52.1%, respectively. The 4‐year relapse‐free survival and survival rates were 54.9% and 50.7% in the LOW group; 61.9% and 53.5% in the HIGH group (P = 0.69 and 0.82, respectively); 60.3% and 50.4% in the single‐dose group; and 57.9% and 53.3% in the fractionated group (P = 0.65 and 0.78, respectively). There was no difference in the incidence of graft versus host disease, interstitial pneumonitis, or venoocclusive disease either between the LOW and the HIGH groups or between the single‐dose and fractionated‐dose TBI groups. The 4‐year estimated cataract incidence was significantly higher in the single‐dose HIGH instantaneous dose rate group than in the LOW instantaneous dose rate TBI group (P = 0.049). Multivariate analyses showed that instantaneous dose rate and fractionation do not influence the relapse‐free and overall survival rates or the incidence of interstitial pneumonitis.
To stereotactically irradiate ellipsoidal inclined arteriovenous malformations (AVMs) with a single isocenter one can use an adjusted inclined irradiation space with a reduced angular range of arcs. ...If one uses the maximum available irradiation space it is necessary to weight some of the arcs in order to closely encompass the lesion. It has been found that there is a relationship between the lesion inclination angle beta and the weights of arcs. Conversely when the beta angle is known, the weights of the arcs can be determined in advance by means of weighting vectors. The dose volume analysis shows that the isodose volumes remain constant for the different weighting vectors except for the 10% isodose volume which increases slightly as the linear weighting vector's slope alpha increases. Moreover, this procedure permits the optimization of the superimposition between the lesion and the reference isodose. These results enable the construction of an "a priori knowledge" database that can be included in an optimization algorithm procedure.
