16 Cervix Carcinoma

326 Cervix Cancer

parameters are correlated (according to the experience of the “groupe des neuf”) with a defined probability of late side effects, in particular for the rectum and the bladder (4,9,30,98). The duration of the brachytherapy treatment can be varied as well as the loading pattern of the implant. As two implantations are performed, the first implant is usually done according to the classical guidelines outlined above, whereas the major individual adaptation is done at the time of the second implant when all individual parameters are available from the dosimetry of the first implant. Typical dimensions and volumes for the 60 Gy brachytherapy volume are height 7 cm, width 6 cm, thickness 5 cm, product 210 cm 3 (corresponding to a computer calculated volume of ~100 cm 3 ). For a combination treatment, in which 40 Gy of external beam therapy are given with open fields the 60 Gy reference volume is the 20 Gy brachytherapy volume (60 - 40=20 Gy) and the dimensions are Height 10 cm, Width 9 cm, Thickness 8 cm, and the product 720 cm 3 (4,19,53) (corresponding to a computer calculated volume of ~360 cm 3 ). During the last decade, the dimensions of these reference volumes have been reduced. Typical doses for rectum and bladder are strongly dependent on the reference volume and the individual topography and for the ICRU reference points range between 60 and 80 Gy and 70 and 90 Gy, respectively (4,19,30,98).

Fig 14.11.B1,2: Anterior-posterior and lateral localisation films indicating the position of the applicator (small diameter), the bladder balloon, the rectal probe and various reference points (pelvic wall point, point A) including ICRU rectum and bladder points.

8.4 Institut Gustave-Roussy method: Individual 60 Gy volume adaptation based on individual moulds (16,37,38,42). The positioning of the sources is dictated by the anatomy of the patient and the topography of the tumour. Individually selected lengths are used for the sources case by case (from 16 - 88 mm, with steps of 8 mm). The uterine sources are usually 48, 56, 64, and 72 mm in length (rare or occasionally 40, 80, 88 mm). They must “cover” at least the two lower thirds of the uterus: the upper limit corresponds to the junction of the upper and middle thirds of the uterus; the lower limit is projected in the plane of the