[en] In local radiation therapy, patients are exposed to radiation not only from the primary beam but also, and more generally, from scattered radiation during irradiation. We have conducted a study to estimate the dose level on testes for 60 patients underwent susdiaphragmatic and subdiaphragmatic lymph node irradiation with 25 MV X rays. Testes of each patient was measured five times while under treatment by using thermoluminescent dosimeters (LiF). In 35 cases, dosimeter showed that radiation was under the additional shield which completed the primary one to reduce exposure. In 41 patients, measurements were performed with microrods which were read with a manual reader and, in the others, an automatic reader and chips were used. This study showed that: -for susdiaphragmatic irradiation, the median dose received by each patient on testes was 0,6% of the reference dose. -for subdiaphragmatic irradiation, the median dose was 5.75 % for cases without additional shield and was 3 % for ones with additional shield

[en] Clinical effects of radiation on bladder are in relation with their effects on various tissues of this organ. The most important is the vessels. According to clinical models; it is possible to evaluate the different factors, especially the dose and the irradiated volume. The risk of complications rise with these two factors. Drugs used in bladder cancer don't seem to increase the risk of complications. The prevention of the late effects lies on the tissue protection and on the precise evaluation of the irradiated volume in view to reduce them. (author)

[en] During total body irradiation, the patient is entirely exposed to radiation and the dose to lungs have to be limited. Personalized shields are make and set between the source and the patient, in front of lungs. The patient and the shields set up are checked before the treatment session with radiographs. Verification films are performed during the treatment sessions with anterior and posterior beams. During the treatment session, the patient may move and his relative positioning can change. Also, for each daily session treatment, his positioning could be different. One way to determine position discrepancies of the shields lungs is to analyse verification films. A study has been achieved comparing positions of lungs and shields edges in digitised simulator and digitised verification images. Discrepancies on distance and angle between similar anatomical landmarks in both images are determined by applying a least squares minimisation approach. In this study, which concerns 29 patients, distance discrepancies are founded from 1,5 to 12,6 mm for the anterior beams and from 1,8 to 15,3 mm for the posterior beams. Angle discrepancies are founded from 0 to 2 degrees

[en] The result of a radiation treatment is linked to the accuracy of the patient's position, his immobility during the treatment time and the repeatability of the patient's position during the various sessions. The psychological aspects which prevent the use of immobilisation constraints have lead radiotherapists to examine the use of artificial vision to perform qualimetry based on immobility and repositioning. As concerns immobility monitoring: the image of the scene, sampled according to a reference grid to reduce the size of the information, is compared in real time to a file which constitutes the reference to the initial position. This enables the detection of non stationary points which are indicative of local movements. To eliminate the artefacts, a check is performed over the eight neighbouring points of each sample, and only the points which represent a real movement are considered. As the quality of detection is linked to the computation time, observation windows are determined by the physician during the first session which enable detection to be limited to observation of the defined fields only. As concerns position monitoring: the positional differences between the position corresponding to the first session taken as a reference, and the position under observation to be monitored, result from the measurements obtained by the co-location of a vector modelling the current image with the vector modelling in the same manner the reference image limited by a window over the part of the image visualising the target volume. A successive presentation is made of the environmental specifications, the heuristics involved in the processing of images providing the elimination of acquisition chain interference, variations in the brightness of treatment rooms and natural physiological movements such as the blinking of cyclids, and the experimental results obtained on site

[en] The clinical and radiological responses after irradiation of brain metastases were compared in 50 patients. A complete response as evidenced by CT scan was achieved in 11 patients, whereas a clinical complete response was observed in 16 cases. There was only 35% agreement between the clinical and the radiological responses. In terms of patient survival, those in whom complete radiological response was obtained has a significantly longer survival time (p = 0.004). Therefore, in evaluating the treatment of brain metastases, it is preferable to determine both the clinical and the radiological responses. The latter seems to be more accurate and justifies the use of repeated CT scans in the follow-up of these patients

[en] Primary cerebral lymphoma is a rare disease with an unfavorable prognosis. Whole brain radiotherapy has been the standard treatment, but neither the optimal radiation fields nor optimal dose level of the regimen are as yet firmly establisheD. From this review of the literature, it seems that the whole brain must be treated, and a boost to the area of the primary site must be discussed. With regard to dose, the radiation dose-response relationship is not clearly proven. Yet, a minimum dose of 40 Gy is necessary, and the maximum dose is set at 50 Gy because of late neurological sequelae. Because of the poor prognosis of this disease and the risk of late sequelae, other avenues have been explored. Chemotherapy has been studied, seem to have a survival advantage and combinations of radiotherapy and chemotherapy, especially with high-dose methotrexate. Because primary cerebral lymphoma is an uncommon disease, randomized clinical trials that compare radiotherapy alone to chemotherapy plus radiotherapy may not be feasible. Finally, even if chemotherapy seems to have a survival advantage, the regimen of chemotherapy is still a matter of debate. (authors)

[en] Published in summary form only

No abstract available

[en] To initiate Intensity-Modulated Radiation Therapy (IMRT) in our department, theoretical cases were used as a training, to define methods of measurements and to verify the software by comparing results of calculation and measurement on a PMMA phantom. Irradiation was performed with 6 and 25 MV X-rays from a linear accelerator. For measurements, films and ionization chambers have been chosen. The comparison between calculations and measurements shows some discrepancies at the level of junctions and also in areas of low doses especially when many segments were used. These theoretical cases provide a first step on the way towards treatments with intensity modulation. (author)

[en] The segmentation allows during a same irradiation session to irradiate separately the prostate and the seminal vesicles. This technique allows to reduce the treated volumes while delivering optimal doses to the prostate and seminal vesicles. (N.C.)