22 Penis Cancer

Penis Cancer 485

Plates A and B are superimposed, with plate B opposite plate A, so that the projection of the tumour can be reproduced on this second plate (Fig 21.6). The apparatus for implantation is chosen according to this precise plan. The holes to be used are selected and marked on plate A, then on plate B. These holes for the passage of needles should, of course, be strictly identical on both plates, and are marked by a coloured dot (Fig 21.7). It has to be stressed that all these procedures can be carried out before the actual implantation, at the consultation following circumcision: accurate provisional dosimetry can be calculated: the duration of the implant is thus predetermined, allowing choice for the start and end of the procedure. The risks of infection linked to the manual preparation of the plates, which are custom-made at the moment of application, can thus be eliminated. The parallelism of the plates and needles is thus ensured, and is maintained throughout the treatment. The use of this new technique of implant significantly saves time and improves logistics. The patient’s tolerance is greatly increased as the risk of infections is reduced and problems of secondary distortion are eliminated. The whole apparatus is lightweight. Finally, a better quality implant is achieved allowing an increase in local control. In this system, hypodermic needles may be replaced by plastic tubes to make PDR therapy possible, but so far no data have been reported.

Fig 21.8: The penis is maintained with a perforated adapted sponge, the radioactive material is pushed away from the testis.

Fig 21.9: Loading of Iridium 192 wire inside the needles

Fig 21.10: Radiograph as a basis for computerized dosimetry.