Biomedical subjects

E Touboul

Publications and source records attributed to E Touboul.

At least 37 records · Page 2Linked to original sources

PubMed2002

[Epidermoid carcinoma of the uterine cervix at operable bulky stages IB and II treated with combined primary radiation therapy and surgery].

PURPOSE: To identify prognostic factors and treatment toxicity in a series of operable bulky stages I and II cervical carcinomas treated with a therapeutic modality combining primary irradiation and surgery. PATIENTS AND METHODS: Between July 1982 and May 1996, 66 patients with bulky squamous-cell cervical carcinomas (stage IB2, IIA, and IIB with 1/3 proximal parametrial invasion) underwent primary external beam pelvic radiation therapy (37.40 Gy to 40 Gy over 4.5 weeks) and low-dose-rate uterovaginal brachytherapy (20 Gy) followed, 5 to 6 weeks later, by class II modified radical hysterectomy with bilateral pelvic lymphadenectomy. The four last patients received concomitant chemotherapy during the first and the fourth radiation week combining 5-FU and cisplatin. A clinical pelvic lymph node involvement had been observed in 7 patients. The clinical median tumor size was 5 cm in diameter (range: 4.5-8 cm). The median follow-up was 97 months. RESULTS: Pathologic complete tumor response in specimen of hysterectomy were observed in 46 patients. Six patients had pathologic unilateral iliac lymph node involvement. The 5- and 10-year specific survival rates were 79 and 74%, respectively. The 5- and 10-year disease-free survival rates were 76% and 71%, respectively. The 10-year local control rate was 85%. The 10-year probability for pelvic recurrence was significantly influenced by the pathologic tumor response: 26% in the residual group vs 5% in the complete tumor response group, P = 0.024). After multivariate analysis, the independent factors decreasing the probability of disease-free survival were: pathologic pelvic lymph node involvement (P = 0.029), and parametrial invasion (P = 0.031). Five late severe complications requiring surgical intervention were observed: 2 bowel obstructions, 1 ureteral stenosis, 1 vesicovaginal fistula, and 1 radiation induced unilateral femoral necrosis. CONCLUSION: A good local control is obtained after combined primary radiation therapy and surgery for bulky stages I and II cervical carcinomas. In our more recent practice, the treatment combines primary concomitant chemoradiation followed by surgery including pelvic and para-aortic lymphadenectomy.

Adult↗

PubMed2002

[Operable stage IB and II cancer of the uterine neck: retrospective comparison between preoperative utero-vaginal curietherapy and initial surgery followed by radiotherapy].

PURPOSE: To identify prognostic factors and treatment toxicity in a series of operable stages IB and II cervical carcinomas. PATIENTS AND METHODS: Between May 1972 and January 1994, 414 patients (pts) with cervical carcinoma staged according to the 1995 FIGO staging system underwent radical hysterectomy with (n = 380) or without (n = 34) bilateral pelvic lymph node dissection. Lateral ovarian transposition to preserve ovarian function was performed on 12 pts. The methods of radiation therapy (RT) were not randomised and depended on the usual practices of the surgical teams. Group I: 168 pts received postoperative RT (64 pts received vaginal brachytherapy alone [mean total dose (MD): 50 Gy], 93 pts had external beam pelvis RT (EBPRT) [MD: 45 Gy over 5 weeks] followed by vaginal brachytherapy [MD: 20 Gy], and 11 pts had EBPRT alone [MD: 50 Gy over 6 weeks]. Group II: 246 pts received preoperative utero-vaginal brachytherapy [MD: 65 Gy], and 32 of theses 246 pts also received postoperative EBPRT [MD: 45 Gy over 5 weeks] delivered to the parametric and the pelvic lymph nodes with a midline pelvic shield. The mean follow-up was 106 months. RESULTS: The 10-year disease-free survival (DFS) rate was 80%. From 75 recurrences, 35 were isolated locoregional. Multivariate analysis showed that independent factors decreasing the probability of DFS were: both exo and endocervical tumour site (p = 0.047), lymph-vascular space invasion (p = 0.041), age < or = 51 yr (p = 0.013), 1995 FIGO staging system (stage IB1 vs stage IIA, p = 0.004, stage IB1 vs stage IB2, p = 0.0009, and stage IB1 vs stage IIB with 1/3 proximal parametrical infiltration, p = 0.00002), and histological pelvic involved lymph nodes (p = 0.00009). Methods of adjuvant RT did not influence the probability of DFS (group I vs group II, p = 0.10). The postoperative complication rate was 10.2% in group I and 8.9% in group II (p = 0.7) but the postoperative urethral complication rate necessitating surgical intervention with reimplantation was lower in group I than in group II (0.6% vs 2.3%, respectively, p = 0.03). The 10-year rate for grade 3 and 4 late radiation complications according to the LENT-SOMA scoring system was 10.4%. EPRT significantly increased the 10-year rate for grade 3 and 4 late radiation complications (yes vs no: 22% vs 7%, respectively, p = 0.0002). CONCLUSION: In our series, the methods of adjuvant RT (primary surgery vs preoperative uterovaginal brachytherapy) do not seem to influence the prognosis of the stage IB, IIA, and IIB (with 1/3 proximal parametrical involvement only) cervical carcinomas. The postoperative EPRT applied according to histopathological risk factors after surgical treatment increases the risk of late radiation complications.

Adult↗

PubMed2001

Conformal radiotherapy (CRT) planning for lung cancer: analysis of intrathoracic organ motion during extreme phases of breathing.

PURPOSE: Conformal radiotherapy beams are defined on the basis of static computed tomography acquisitions by taking into account setup errors and organ/tumor motion during breathing. In the absence of precise data, the size of the margins is estimated arbitrarily. The objective of this study was to evaluate the amplitude of maximum intrathoracic organ motion during breathing. METHODS AND MATERIALS: Twenty patients treated for non-small-cell lung cancer were included in the study: 10 patients at the Institut Curie with a personalized alpha cradle immobilization and 10 patients at Tenon Hospital with just the Posirest device below their arms. Three computed tomography acquisitions were performed in the treatment position: the first during free breathing and the other two during deep breath-hold inspiration and expiration. For each acquisition, the displacements of the various intrathoracic structures were measured in three dimensions. RESULTS: Patients from the two centers were comparable in terms of age, weight, height, tumor site, and stage. In the overall population, the greatest displacements were observed for the diaphragm, and the smallest displacements were observed for the lung apices and carina. The relative amplitude of motion was comparable between the two centers. The use of a personalized immobilization device reduced lateral thoracic movements (p < 0.02) and lung apex movements (p < 0.02). CONCLUSION: Intrathoracic organ movements during extreme phases of breathing are considerable. Quantification of organ motion is necessary for definition of the safety margins. A personalized immobilization device appears to effectively reduce apical and lateral displacement.

Aged↗

PubMed2001

Adenocarcinoma of the endometrium treated with combined irradiation and surgery: study of 437 patients.

PURPOSE: To identify prognostic factors and treatment toxicity in a series of operable endometrial adenocarcinomas. METHODS AND MATERIALS: Between November 1971 and October 1992, 437 patients (pts) with endometrial carcinoma, staged according to the 1988 FIGO staging system (225 Stage IB, 107 Stage IC, 4 Stage IIA, 35 Stage IIB, 30 Stage IIIA, 6 Stage IIIB, and 30 Stage IIIC), underwent total abdominal hysterectomy and bilateral salpingo-oophorectomy without (n = 140) or with (n = 297) pelvic lymph node dissection. The chronology of adjuvant RT was not randomized and depended on the usual practices of the surgical teams. Seventy-nine pts (Group I) received preoperative low-dose-rate uterovaginal brachytherapy (mean dose [MD]: 57 Gy). Three hundred fifty-eight pts (Group II) received postoperative RT. One hundred ninety-six pts received low-dose-rate vaginal brachytherapy alone (MD: 50 Gy). One hundred fifty-eight pts had external beam pelvic RT (MD: 46 Gy) followed by low-dose-rate vaginal brachytherapy (MD: 17 Gy). Four pts had external beam pelvic RT alone (MD: 47 Gy). The mean follow-up from the beginning of treatment was 128 months. RESULTS: The 10-year disease-free survival rate was 86%. From 57 recurrences, only 12 were isolated locoregional recurrences. The independent factors decreasing the probability of disease-free survival were as follows: histologic type (clear-cell carcinoma, p = 0.038), largest histologic tumor diameter >3 cm (p = 0.015), histologic grade (p = 0.008), myometrial invasion > 1/2 (p = 0.005), and 1988 FIGO staging system (p = 9.10(-8)). In Group II, the addition of external beam pelvic RT did not seem to independently improve vaginal or pelvic control. The postoperative complication rate was 7%. The independent factors increasing the risk of postoperative complications were stage FIGO (p = 0.02) and pelvic lymph node dissection (p = 0.011). The 10-year rate for Grade 3 and 4 late radiation complications according to the LENT-SOMA scoring system was 3.1%. External beam pelvic RT independently increased the rate for Grade 3 and 4 late complication (RR: 5.6, p = 0.0096). CONCLUSION: Postoperative external beam pelvic RT increases the risk of late radiation complications. After surgical and histopathologic staging with pelvic lymph node dissection, in subgroup of "intermediate-risk" patients (Stage IA Grade 3, IB-C and II), postoperative vaginal brachytherapy alone is probably sufficient to obtain a good therapeutic index. Results for patients with Stage III tumor are not satisfactory.

Adenocarcinoma↗

PubMed2001

CT and (18)F-deoxyglucose (FDG) image fusion for optimization of conformal radiotherapy of lung cancers.

PURPOSE: To validate a computed tomography (CT) and (18)F-deoxyglucose (FDG) image fusion procedure and to evaluate its usefulness to facilitate target definition and treatment planning in three-dimensional conformal radiation therapy (3D-CRT) for non-small-cell lung cancer. METHODS AND MATERIALS: Twelve patients were assessed by CT and FDG-coincidence mode dual-head gamma camera (CDET) before radiotherapy. The patients were placed in a similar position during CT and FDG-CDET. Matching was achieved by minimizing the cost function by 3D translation and rotation between four landmarks drawn on the patient's skin. Virtual simulation was performed from image fusion and estimated dose-volume histograms (DVH) were calculated. RESULTS: Quantitative analysis indicated that the matching error was < 5 mm. Fusion of anatomic and metabolic data corrected staging of lymph nodes (N) for 4 patients and staging of metastases for 1 patient. In these 5 patients, DVH revealed that the lung volume irradiated at 20 Gy (Vl(20)) was decreased by an average of 22.8%, and tumor volume irradiated at the 95% isodose (V(95)) was increased by 22% and 8% for 2 patients, respectively, and was decreased by an average of 59% for 3 patients after fusion. No difference in terms of Vl(20) and V(95) was observed for the other 7 patients. CONCLUSION: We have validated CT and FDG-CDET lung image fusion to facilitate determination of lung cancer volumes, which improved the accuracy of 3D-CRT.

Carcinoma, Non-Small-Cell Lung↗

PubMed2001

Lens epithelial cell protection by aminothiol WR-1065 and anetholedithiolethione from ionizing radiation.

Lens epithelium disorganization, glutathione (GSH) depletion, and epithelial cell death have been incriminated in the cytopathogenic mechanisms that lead to cataract formation following UVB and x-ray exposures. The objective of this study was to determine the in vitro capacity of the aminothiol WR-1065, the active metabolite of amifostine, and anetholedithiolethione (ADT or Sulfarlem) to protect bovine lens epithelial cells against x-ray irradiation. WR-1065 and ADT were used at a concentration of 20 microM. A single dose of 10 Gy was delivered at a rate of 2 Gy/min. Fluorimetric assays were then performed using a neutral red probe to evaluate cell viability, a Hoechst 33342 probe (HO) to evaluate nuclear condensation and apoptosis, and a monobromobimane probe to estimate the intracellular GSH pool. Twenty-four hours after x-ray exposure, cells pretreated with WR-1065 showed increased GSH levels, improved cell viability, and decreased HO fluorescence in addition to a lesser proportion of cells with apoptotic nuclear modifications. Between 72 and 120 hr postirradiation, ADT-pretreated cells also showed increased intracellular GSH levels and cell viability and decreased HO fluorescence and apoptotic cell morphology. This in vitro study demonstrates that WR-1065 and ADT protects lens epithelial cells from x-ray injury; thus, ADT and amifostine are appropriate candidates for clinical trials in humans. They are currently used in preventing radiation-induced xerostomia and should be further tested in the prevention of late radiation-induced ocular complications such as sicca syndrome and cataract.

Amifostine↗

PubMed2001

Teleconsultation before chemotherapy for recently operated on patients.

BACKGROUND: Some operated on cancer patients require specialized complementary chemotherapy. Often, this takes place in another institution, where the patient consults the medical oncologist before hospitalization. The aim of this study was to analyze the potential benefit of a videoconference consultation within this framework. METHODS: Sixteen operated on cancer patients hospitalized in the Surgical Unit received a teleconsultation in the presence of their surgeon and with the chemotherapist at some distance. During this period, the modalities of chemotherapy proposed, the duration of the teleconsultation, the economy of transport, and so on were noted. Twenty-four hours later each patient filled in a questionnaire aimed at, one, evaluating the quality of the image on an visual analogue scale (VAS) and the potential inconvenience involved; and two, evaluating the index of patient satisfaction on VAS. Furthermore, the last 12 patients filled in a questionnaire adapted to each of them, according to the information they had received. Each correct answer was noted 1, and each incorrect answer was noted 0. A memorization percentage was deduced. RESULTS: The average age of the 16 patients was 63.4 years (range 46 to 78). The average duration of the teleconsultation was 27 minutes (12 to 40). The index of image satisfaction was 61.3%. As for the last 12 patients, 9.8 questions (7 to 12) enabled the calculation at 24 hours of the percentage of data retained by the patient (memorization index) based on the modalities and consequences of the chemotherapy. The percentage of correct answers was 80.5%. Fourteen of the 16 patients considered that teleconsultation had its advantages. Two patients would have preferred a classic consultation. The global satisfaction index was 79.9%. The average cost of functioning per patient was 187.76 FF A saving in transport of 509.92 FF was recorded per patient. CONCLUSIONS: In the context of this original study, teleconsultation neither altered the doctor-patient relationship nor the quality of the message transmitted. Furthermore, it encourages closer links between complementary teams working at a distance and multidisciplinarity in cancerology.

Aged↗

PubMed2001

Structure-activity relationships in platelet-activating factor (PAF). 11-From PAF-antagonism to phospholipase A(2) inhibition: syntheses and structure-activity relationships in 1-arylsulfamido-2-alkylpiperazines.

1-Benzoyl-2-alkyl piperazines are strong inhibitors of Group I and II secreted PLA(2)s. An improvement of their activity was obtained by replacing the amide function by a sulfamide and by introduction of electrodonor substituents on the para position of the benzenesulfonyl moiety. Neither the position on one of the carbon of the piperazine ring nor the absolute configuration of this carbon have an effect on the affinity for one or the other group of PLA(2), but the lipophilicity remains for these series an essential parameter. In addition structure-activity relationships allow new hypothesis on interaction of these piperazine derivatives with the catalytic site of PLA(2)s.

Animals↗

PubMed2001

[Automatic definition of prescription isodose for stereotaxic radiation of arteriovenous malformations].

PURPOSE: To evaluate dosimetric consequences generated by the automatic definition based on lesion coverage of prescription isodose. A clinical series of 124 arteriovenous malformations was analysed. Plan quality was quantified by the standard deviation of the differential dose volume histogram calculated in the lesion. MATERIAL AND METHODS: We define two quantitative protocols based on lesion coverage for the automatic definition of prescription isodose using a volumetric definition of coverage (90% of lesion volume), and an isodose-based definition proposed by RTOG (prescription isodose equals minimum isodose in the lesion divided by 0.9). RESULTS: We have evaluated the plans obtained for these two protocols, calculating several dose-volume indices. These indices are presented as a function of dose-volume histogram standard deviation in order to quantify the consequences of their variations for this representative series of plans. The margin our team tolerates is such that the sum of underdosed lesion and overdosed healthy tissues factors remains lower than one. Protocol based on volumetric coverage gives results situated within this margin. Protocol based on RTOG definition produces conformation indices that could be greater than 1. CONCLUSION: The absolute dose would be decided taking into account examined dose-volume indices and clinical data. A protocol for automatic definition of prescription isodose using volumetric lesion coverage seems to be more judiciously adapted to arteriovenous malformation conformal plans in stereotactic conditions because of variations observed in the overdosage of healthy tissues.

Algorithms↗

PubMed2001

[Breast-conserving surgery and irradiation for early breast cancer: value of surgical clips in the surgical cavity].

PURPOSE: To evaluate, qualitatively and quantitatively, the role of surgical clips in planning the tumor bed electron or brachytherapy boost in patients undergoing breast-conserving surgery and radiotherapy. PATIENTS AND METHODS: In 60 patients with breast cancer stage I or II, the excision cavity boundaries were marked by clips at surgery. Patients received a boost with brachytherapy (n = 51) or electron beam (n = 9) after whole breast irradiation. The boost target volume was first planned using clinical, mammography and operative information and its accuracy evaluated by screening the surgical clips and, if necessary, adjusting the field to encompass all clips and to include the scar. Dosimetry was retrospectively performed for each brachytherapy patient and for each surgical clip. RESULTS: It was necessary to modify the target volume field in 11 cases (18%). The average dose received by the surgical clips was 116.1% of the dose delivered to the reference isodose (median: 101.75%, range: 16-457%). However, dose heterogeneity was important in the same patient and between patients. CONCLUSION: Delineation of the boost target volume with surgical clips is more accurate than with clinical landmarks alone but this technique does not allow measurements of the clip-chest wall and clip-skin distances. Virtual simulation with CT-scan cuts is recommended for optimising boost planning.

Brachytherapy↗

PubMed2001

[Physical and methodological aspects of multimodality imaging and principles of treatment planning in 3D conformal radiotherapy].

The recent evolutions of the imaging modalities, the dose calculation models, the linear accelerators and the portal imaging permit to improve the quality of the conformal radiation therapy treatment planning. With DICOM protocols, the acquired imaging data coming from different modalities are treated by performant image fusion algorithms and yield more precise target volumes and organs at risk. The transformation of the clinical target volumes (CTV) to planning target volumes (PTV) can be realised using advanced probabilistic techniques based on clinical experience. The treatment plans evaluation is based on the dose volume histograms. Their precision and clinical relevance are improved by the multi-modality imaging and the advanced dose calculation models. The introduction of the inverse planning systems permitting to realise modulated intensity radiation therapy generates highly conformal dose distributions. All the previously cited complex techniques require the application of rigorous quality assurance programs.

Dose Fractionation, Radiation↗

PubMed2001

[Radiation-induced cataract: physiopathologic, radiobiologic and clinical aspects].

Cataractogenesis is a widely reported late effect of irradiated crystalline lens. In this review the authors discussed the different aspects of radiation cataract pathogenesis, and the different mechanisms involved in the lens opacification, particularly the epithelium modifications such as epithelial cell death. The authors also reported the influence of radiation exposure on cataract formation following total body irradiation (TBI) and autologous or allogeneic bone marrow transplantation for hematologic malignancies. Moreover, the radiobiological parameters are not studied for the crystalline lens of human. We applied for the first time the linear-quadratic (LQ) and biological effective dose (BED) concept to TBI data. The calculated value of alpha/beta of 1 Gy is in the range of the values reported for the other late responding tissues. The other risk factors for cataract development after TBI such as age, gender, central nervous system boost, long-term steroid therapy and heparin administration are discussed. In terms of cataract or sicca syndrome prevention, numerous compounds have been successfully tested in experimental models or used for the prevention of radiation-induced xerostomia in patients treated for head and neck cancer. However, none of them has been clinically evaluated for ocular radiation late effects prevention. In this report the authors discussed some of the radioprotectors potentially interesting for radiation-induced cataract or sicca syndrome prevention.

Age Factors↗

PubMed2001

[Comparison of biological functional assessment in intensity-modulated radiotherapy: two-dimensional study].

Modulated intensity dose distributions are obtained by inverse planning. It requires an inversion algorithm and an objective function that can be physical or biological. The biological objective functions aim at quantifying the probability of the favourable end of the treatment. The inversion algorithm used is analytical and is based on the mathematical analysis of the singular values decomposition. It proposes as many solutions as there are elementary beams. From the Tumour Control Probability, Normal Tissue Complication Probabilities and complication free tumour control, three biological assessment functions of the proposed solutions are compared with the least square difference between the prescribed and obtained dose distributions. We used a simplified irradiation configuration: Brahme's dose prescription (2D modelling of a prostate) and 9 beams (1D). The choice by mean of biological criterion of the optimal solution makes it possible to increase the average dose in the tumour, so as its homogeneity compared to physical optimisation. Conversely, the organs at risk are then less protected. The laying down of relevant constraints makes it possible to obtain satisfactory dose distributions. Concerning the validity of the models and data used, some limitations appear. At present time, it seems to exclude the use in clinical routine of an only biological optimisation. The future availability of new biological data will allow the development and in particular the clinical use of biological optimisation.

Algorithms↗

PubMed2001

[Standards, options and recommendations for the management of locally advanced non small cell lung carcinoma].

CONTEXT: The "Standards, Options and Recommendations" (SOR) project, started in 1993, is a collaboration between the Federation of the French Cancer Centres (FNCLCC), the 20 French Cancer Centres and specialists from French Public Universities, General Hospitals and Private Clinics. The main objective is the development of clinical practice guidelines to improve the quality of health care and outcome for cancer patients. The methodology is based on literature review and critical appraisal by a multidisciplinary group of experts, with feedback from specialists in cancer care delivery. OBJECTIVES: To develop clinical practice guidelines according to the definitions of the Standards, Options and Recommendations project for the management of locally advanced non small cell lung carcinoma. METHODS: Data were identified by searching Medline and the personal reference lists of members of the expert groups. Once the guidelines were defined, the document was submitted for review to independent reviewers and to the medical committees of the 20 French Cancer Centres. RESULTS: The main recommendations are: 1) The management of the locally advanced non small cell lung carcinoma has two main goals: firstly to obtain local control of the disease (or to at least delay local progression in order to improve the survival or relapse free survival), and secondly to prevent the development of metastases. 2) There is a consensus that locally advanced non small cell lung carcinoma should be irradiated. External beam radiotherapy should be of optimal quality and delivered at a minimal dose of 60 Gy by standard fractionation. For patients with a poor life expectancy, this can be delivered as a split-course or hypofractionated scheme. 3) Treatment for patients with a performance status of 0-1 should consist of short duration induction chemotherapy (with a least two drugs one of which must be cisplatin), combined sequentially with conventional radiotherapy. 4) Surgery is contraindicated in extensive N3 disease. Combined radio-chemotherapy (adjuvant or neoadjuvant) is not indicated outside clinical trials. Surgery is justified in stage N2 disease as good local control can be achieved. T4-N0 disease should be treated surgically with curative intent.

Adult↗

PubMed2001

[Radiotherapeutic basis of radiosurgery as applied to cerebral arteriovenous malformations: dose-volume effects].

BACKGROUND AND PURPOSE: To attempt to analyze the basic effects of radiosurgery as applied to cerebral arteriovenous malformations. METHODS: We reviewed and discussed the previous issues of the international literature concerning radiobiological principles of radiosurgery of arteriovenous malformations. RESULTS: The irradiated volume contained both a target volume consisting of abnormal vessels of the nidus often embedded within connective tissue stroma and the surrounding normal brain tissue. These were late-responding tissues after the radiation and sensitive tissues to high dose per fraction. There was not resistant hypoxic cell that could be killed efficiently with fractionated treatment. The therapeutic ratio between damage in the arteriovenous malformation nidus and late complications in the surrounding tissues was independent of fractionation. Furthermore, sterilization of all clonogenic cells in the target volume was not necessary to obtain complete obliteration of arteriovenous malformation. Consequently, there was nothing to be gained by a fractionated course relative to a stereotactic high single-dose irradiation for a small targeted volume (<=25 mm in diameter or<=4 200 mm(3)). The minimum target dose (Dmin) seemed to be the dosimetric independent predicting factor for complete obliteration. The Dmin-response relationship suggested a threshold dose of 5 Gy to 10 Gy and the better effects following Dmin from 20 Gy to 25 Gy. A Dmin above 25 Gy significantly increased the risk of serious late complications. The treated volume seemed to be the significant independent predicting dosimetric factor for developing persistent symptomatic sequelae. The optimum dose to deliver to obtain complete obliteration of an arteriovenous malformation was selected by balancing the expected obliteration rate for each dose with the corresponding risks from radiosurgery depending on size, location, shape and dose distribution. CONCLUSION: Although the basic pathological process is still uncertain there is a strong rationale for stereotactic radiotherapy delivered in a high single-dose for small arteriovenous malformations.

Blood Vessels↗

PubMed2001

[Technique of Linac radiosurgery for cerebral arteriovenous malformations].

BACKGROUND AND PURPOSE: Description of the irradiation technique used by our group since 1986 for radiosurgery of cerebral arteriovenous malformations using Xrays minibeams from a linear accelerator. Method. The technique was elaborated by O. Betti in the early 80. He used several coronal arcs to irradiate the center of the target with X rays circular minibeams. Their diameter (6 to 20 mm) is chosen according to the size of the nidus. The patient is seated in a specially built armchair. His head is immobilized with the Talairach frame afixed in the calvarium by 4 special screws: they allow to remove the frame after stereotactic angiography and/or CTscan and to replace it to perform the stereotactic irradiation. The frame and the head rotate around an horizontal axis passing by the linac isocenter ie the center of the target volume. The combination of both movements: rotation of the Linac and rotation of the stereotactic frame covers a spherical sector representing the surface of portals of entry of the minibeams. The frame can slide on a plate allowing access to the entire brain. Results. The special seat and the frame are movable on curved rails allowing to avoid or reduce irradiation of the body of the patient. CONCLUSION: We have been using this system of irradiation in the seated position since 1986 to treat more than 900 patients.

Dose Fractionation, Radiation↗

PubMed2001

[Technologic developments in radiotherapy and stereotactic radiosurgery].

We present a review of current technological progress enabling improvement in the quality of stereotactic irradiations: imaging fusion; individual adaptation of dosimetric planning to the shape of the target thanks to several collimation systems, spatial modulation of the beam with the use of multileaf microcollimators, beam intensity modulation, robotisation of the materials, owing to hardware and software developments.

Brain Neoplasms↗

PubMed2001

[Cerebral arteriovenous malformations treated by radiosurgery: a series of 705 cases].

BACKGROUND AND PURPOSE: After a review of the main radiosurgical published series, to evaluate our own series of 705 patients with cerebral arteriovenous malformations treated by radiosurgery alone or in combination with embolization or surgery. PATIENTS: and method. From January 1984 to December 1998, 705 patients were treated by a multidisciplinary team including neurosurgeons, neuroradiologists, radiophysicians and radiotherapists. Age of revelation of the cerebral arteriovenous malformations ranged between birth to 73 years (mean 27, median 25). Age at time of radiosurgery ranged between 7 and 75 years (mean 33, median 31). There were 410 males for 295 females (sex- ratio 1.4). Symptoms of revelation were hemorrhage for 59%, seizures for 23%, headaches for 14% and progressive deficits for 4%. Discovery of cerebral arteriovenous malformation was fortuitous in 4% of cases. Repartition following Spetzler's grading was 12% in grade I, 36% in grade II, 40% in grade III, 12% in grade IV and 0% in grade V. Maximal size ranged between 4 and 60 mm (mean 23, median 20). Volume ranged between 0.2 and 24.3 cc (mean 3.8, median 2.8). Majority of cerebral arteriovenous malformations were large size (42% with size higher than 25 mm) and large volume (54% higher than 10 cc. 54% of patients had treatment prior radiosurgery: 38% had embolization, 10% were operated, 4% were treated by radiosurgery (reirradiation) and 3% were operated and embolized. RESULTS: Overall complete obliteration rate was 55%. The obliteration rate was correlated with size (77% for cAVMs lower than 15 mm, 62% for cerebral arteriovenous malformations between 15 and 25 mm, and 44% for cerebral arteriovenous malformations higher than 25 mm), with volume (94% for cerebral arteriovenous malformations lower than 1 cc, 64% between 1 and 4 cc, 48% between 4 and 10 cc, and 62% for cerebral arteriovenous malformations higher than 10 cc), dose at reference isodose, minimal dose, morphological parameters (presence of dural components, arteriolovenous fistula, plexiform angioarchitecture, arterial steal, arterial recruitment, deep exclusive drainage, venous plicature, venous confluence, venous ectasia, venous reflux), sectional topography and good recovery of the target. Embolization was a confusion factor not associated with obliteration rate. After multivariate analysis, only Dmin and complete coverage of the cerebral arteriovenous malformations were correlated with obliteration rate. Delay of obliteration was significantly correlated after multivariate analysis with Dmin, complete coverage, arteriolovenulary angioarchitecture (positive correlation) and venous ectasia (negative correlation). CONCLUSION: Overall complete obliteration rate is unreliable data to assess efficacy of radiosurgical method in the tretment of cerebral arteriovenous malformations. The obliteration rate must be interpretated after stratification on several morphological and dosimetric parameters.

Adolescent↗