A comparison of the late radiation changes after three schedules of radiotherapy.

The late radiation change observed in 15 patients treated for carcinoma of oral cavity or oropharynx using continuous hyperfractionated accelerated radiotherapy (CHART) was compared to that seen in 15 similar patients treated with conventional radiotherapy. The average follow up was, 31 and 33 months, respectively. A new dictionary for the recording of radiation morbidity, developed in our centre, was employed and proved highly satisfactory in the recording of the changes observed in these patients and also in a third group treated by a combination of chemotherapy and hypofractionated radiotherapy in hyperbaric oxygen. The dictionary was able to record all the morbidity clinically seen with these three treatment schemes. The late changes observed in skin and mucosa with CHART were similar to those observed with conventional radiotherapy, but hair regrowth was observed in six out of 10 men treated with CHART compared with persistent, partial or complete hair loss in all nine men treated with the conventional scheme; after CHART there was also a trend towards less taste impairment and less severe dryness of mouth.

[External ionizing radiation on the prosthesis-arterial anastomosis for the prevention of intimal hyperplasia and study of biomechanical resistance. Experiments and results]. / Radiations ionisantes délivrées par voie externe sur l'anastomose prothéto-artérielle pour limiter l'hyperplasie intimale et étude de la résistance biomécanique. Expérimentations et résultats.

PURPOSE: To evaluate the use of external ionizing radiation for the prevention of intimal hyperplasia in anastomosis between PTFE and artery. METHODS: Bypass using a 6 mm PTFE was performed on a swine subrenal aorta with a distal conventional anastomosis (N = 35) associated (test group; N = 17) or not (control group; N = 18) with post-operative external radiation (20 Gy) on this anastomosis. At 45 days, histological studies and morphometric studies were performed on the aorta receiving the anastomosis. Two protocols were performed, the first protocol with standard analysis and the animals were randomly assigned to either group (test group; N = 11 and control group; N = 13) and the second protocol with test of extraction comparing the biomechanical resistance between the irradiated group (N = 6) and the control group (N = 5). RESULTS: Twenty-one animals survived the procedure in the first protocol, 11 in the second. The endothelium was restored in either group. Histological recasting was observed in the media after radiation with fibrosis and areas of necrosis. Intimal thickness was significantly lower after irradiation in the heel (P < 0.01), the head (P < 0.01) and the suture line (P < 0.001) of the artery in the first protocol. The intimal thickness was also significantly lower in the second protocol after radiation in the heel (P < 0.05) and the head of the artery (P < 0.05). There was no difference between the two groups comparing the resistance. CONCLUSION: After external irradiation, the thickness parameter of the intima decreased significantly in comparison with the control group with similar resistance. Media fibrosis and necrosis need to be confirmed by further investigation.

[Repositioning accuracy of cerebral fractionated stereotactic radiotherapy using CT scanning]. / Evaluation par tomodensitométrie du repositionnement en radiothérapie stéréotaxique fractionnée cérébrale.

PURPOSE: To evaluate the accuracy of patient repositioning in fractionated cerebral stereotactic radiotherapy using a Brain Lab stereotactic cranial mask in conjunction with standard dental fixation. PATIENTS AND METHODS: Fifty planning and checking CT scans were performed in 25 patients. The check CT scan was performed before or after one of the three sessions of treatment. Coregistration to the planning CT scan was used to assess alignment of the isocentre to the reference markers. The relative position of the PTV with regard to isocentre allowed us to determine its total displacement (3D vector). RESULTS: Mean isocentre translations (+/-SD) taking into account direction were -0.01+/-0.7, -0.2+/-1.3 and 0.07+/-0.5mm in mediolateral, craniocaudal and anteroposterior directions respectively. Mean rotations (+/- SD) were -0.02+/-0.6, -0.08+/-0.3 and -0.1+/-0.3 degree in mediolateral, craniocaudal and anteroposterior axes respectively. Mean overall PTV displacement was 1.8+/-1.5mm. PTV displacement was smaller than 2 and 3mm in 19/25 and 23/25 patients respectively. CONCLUSION: The accuracy of patient positioning using a stereotactic cranial mask system is similar to those reported in the literature and shows a satisfactory reproducibility with a standard dental fixation.