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Biomedical subjects

F Reboul

Publications and source records attributed to F Reboul.

63 records · Page 4Linked to original sources
PubMedDate not supplied

[Dosimetric evaluation of conformal radiotherapy: conformity factor].

The aim of three-dimensional conformal therapy (3DCRT) is to treat the Planning Target Volume (PTV) to the prescribed dose while reducing doses to normal tissues and critical structures, in order to increase local control and reduce toxicity. The evaluation tools used for optimizing treatment techniques are three-dimensional visualization of dose distributions, dose-volume histograms, tumor control probabilities (TCP) and normal tissue complication probabilities (NTCP). These tools, however, do not fully quantify the conformity of dose distributions to the PTV. Specific tools were introduced to measure this conformity for a given dose level. We have extended those definitions to different dose levels, using a conformity index (CI). CI is based on the relative volumes of PTV and outside the PTV receiving more than a given dose. This parameter has been evaluated by a clinical study including 82 patients treated for lung cancer and 82 patients treated for prostate cancer. The CI was low for lung dosimetric studies (0.35 at the prescribed dose 66 Gy) due to build-up around the GTV and to spinal cord sparing. For prostate dosimetric studies, the CI was higher (0.57 at the prescribed dose 70 Gy). The CI has been used to compare treatment plans for lung 3DCRT (2 vs 3 beams) and prostate 3DCRT (4 vs 7 beams). The variation of CI with dose can be used to optimize dose prescription.

Bronchial Neoplasms↗
PubMedDate not supplied

[Preoperative concurrent radiochemotherapy for cancer of the rectum].

PURPOSE: To evaluate retrospectively treatment-related morbidity of concurrent radiotherapy and chemotherapy for rectal cancer. PATIENTS AND METHODS: Between 1992 and 1995, 38 patients (median age: 60) were treated for locally advanced resectable rectal cancer. Median dose of radiotherapy was 45 Gy/25 fractions/5 weeks. Chemotherapy consisted of two courses of 5-fluorouracil and leucovorin administered during the first and the fifth weeks of radiotherapy. Median dose of 5-fluorouracil was 350 mg/m2/day, and median dose of leucovorin was 20 mg/m2/day, day 1 to day 5. Surgery was performed 5 weeks after completion of radiotherapy. RESULTS: Before surgery, one patient died of febrile neutropenia and sepsis after two cycles of chemotherapy and 45 Gy. Main pre-operative grade 3-4 toxicities were respectively: neutropenia: 3%; nausea/vomiting: 3%; diarrhea: 3%; proctitis: 5%; radiation dermatitis: 8%. Twenty-six patients underwent a low anterior resection and 11 an abdomino-perineal resection. A temporary colostomy was performed in 12 patients. Pathologic complete response rate was 27%. There was one post-operative death due to thromboembolic disease. Major post-operative grade 3-4 complications were: pelvic infection: 14%; abdominal infection: 5%; perineal sepsis: 8%; anastomotic dehiscence: 8%; cardiac failure: 5%. Delayed perineal wound healing was observed in six patients. No significant prognosic factor of post-operative complications has been observed. Median duration of hospitalization was 22 days. With a median follow-up of 24 months, 2-year overall and disease-free survival rates were 82 and 64%. CONCLUSION: Tolerance of preoperative concurrent chemoradiotherapy was acceptable. Ongoing controlled studies will assess the impact of this combined treatment on survival.

Adenocarcinoma↗
PubMedDate not supplied

[Conservative treatment of bladder cancers with radiotherapy and concurrent chemotherapy: results and perspectives].

Therapeutic strategies for muscle invasive bladder cancer are currently evolving. Transurethral surgery followed by concurrent chemotherapy and radiotherapy is the best treatment for patients not suitable for radical cystectomy. This conservative approach may be proposed for operable patients with similar survival than after cystectomy. Intermediate evaluation of response is necessary, as response is the more discriminant prognostic factor for local control. Non responders would be assigned for immediate cystectomy. Morbidity and results of salvage cystectomy are poorly evaluated and probably depending from time from initial treatment and dose of radiation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMedDate not supplied

[Definition of prostatic contours using tomodensitometric slices: study of differences among radiotherapists and between examinations].

Accuracy of conformal treatment planning for prostatic radiotherapy is based on the contours of target volumes (prostate +/- seminal vesicles) and normal tissues (rectum and bladder), drawn on CT (computed tomography) images by radiation oncologists. The interpretation of a given CT image can be different from one radiation oncologist to another, and may change in time with the state of filling of the bladder and of the rectum during the treatment. In order to quantify these variations, 12 patients treated with conformal radiotherapy for prostate carcinoma (pelvis 40 Gy/20 sessions + prostate 30 Gy/15 sessions) had two series of CT at one month intervals. Contouring of prostate, rectum and bladder were performed independently on each CT by two radiation oncologists. The first CT scan (planning CT) and the first series of contours (planning contours) were used for treatment planning. The contours of the second scan were compared to the planning contours after image fusion based on manual superimposition of bony anatomy of the two sets of CT images. Coherence ratio were defined to measure discrepancies in prostate volumes between radiation oncologists (RCE) and between scans (RCT). The mean RCE was 38 +/- 7% (1 standard deviation). Those discrepancies were primarily located at the prostate apex and at the interface between bladder and prostate and between rectum and prostate. The mean RCT was 42 +/- 8% (1 sigma). Those discrepancies were due to the prostate motion related to the state of filling of the rectum and bladder. For bladder and rectal walls, less important differences were observed between the two radiation oncologists for the same CT (4.5% for rectal volume receiving 65 Gy or more, 3% for bladder volume receiving 65 Gy or more). However, important differences in bladder and rectal volumes receiving 65 Gy or more (16% and 7% respectively) were noted for the same patient from a CT to another due to the variation in bladder or rectal filling. New techniques for planning CT acquisition are needed to decrease the discrepancies due to contouring. The treatment must, as far as possible, be delivered with an empty bladder and rectum in order to ensure a good reproduction of the initially planned treatment.

Anthropometry↗
PubMedDate not supplied

[Radiological diagnosis of tumoral lipomatosis of the renal sinus. The role of arteriography (author's transl)].

In twenty cases of pseudo-tumoral sinusal lipomatosis for which the patients had undergone renal arteriography, the authors investigated the urographical and arteriographical clinical signs by comparing them with the previously published data. After reviewing these various elements and considering the various possible diagnoses, they came to the conclusion that, although the arteriographic signs are quite distinctive, they are not absolutely essential for diagnosis of this disorder--which it should be possible to confirm unreservedly from the urographical data in all cases in which there are considerable anatomical lesions. A well-managed urographical technique and careful assessment of the facts should allow arteriography to be discarded, indications for this only being justified where there is an associated symptomatology, especially haematuria.

Adult↗