This paper, “Coronographie interferéntielle pour la mission spatuale DARWIN: expérience de validation en laboratoire," was presented as part of International Conference on Space Optics—ICSO 1997, held in Toulouse, France.

The DARWIN mission is a project of the European Space Agency that should allow around 2012 the search for extrasolar planets and a spectral analysis of their potential atmosphere in order to evidence gases and particularly tracers of life. The principle of the instrument is based on the Bracewell nulling interferometer. It allows high angular resolution and high dynamic range. However, this concept, proposed more than 20 years ago, has never been experimentally demonstrated in the thermal infrared with high levels of extinction. We present here a laboratory monochromatic experiment dedicated to this goal. A theoretical and numerical approach of the question highlights a strong difficulty: the need for very clean and homogeneous wavefronts, in terms of intensity, phase and polarisation distribution. A classical interferometric approach appears to be insufficient to reach our goals. We have shown theoretically then numerically that this difficulty can be surpassed if we perform an optical filtering of the interfering beams. This technique allows us to decrease strongly the optical requirements and to view very high interferometric contrast measurements with commercial optical pieces. We present here a laboratory interferometer working at 10,6 microns, and implementing several techniques of optical filtering (pinholes and single-mode waveguides), its realisation, and its first promising results. We particularly present measurements that exhibit stable visibility levels better than 99,9% that is to say extinction levels better than 1000.

The DARWIN mission aims at directly detecting exoplanets, particularly telluric ones, around nearby stars and at performing a spectral analysis of their potential atmosphere. The major difficulty in achieving this goal is the huge luminosity contrast between the star and its possible planet(s). The mission concept is based on the star light rejection by nulling interferometry. This concept has never been experimentally demonstrated with high values of rejection (10(5)) in the thermal infrared where DARWIN will observe. In this paper, we describe a laboratory test-bed that uses a CO2 laser at 10.6 mum to achieve this goal in a monochromatic case. We describe its principle, its sub-systems, their realizations and the first results we obtained with this interferometer.

L'observatoire DARWIN possedera un instrument interferometrique dedie a la recherche et a la spectroscopie de planetes extrasolaires, Cet instrument fonctionne suivant le principe du coronographe interferometrique de Bracewell, ou interferometre en frange noire, propose des 1978, mais jusqu'a present, jamais demontre experimentalement dans l'infrarouge thermique, avec de fortes extinctions. Nous avons montre que de fortes extinctions interferometriques ne peuvent etre obtenues avec des optiques « classiques » qu'a condition de nettoyer les faisceaux par filtrage optique lors de la recombinaison. Apres avoir rappele brievement le principe de l'interferometre en frange noire, nous presentons les differentes techniques de filtrage optique necessaires a sa realisation. Nous presentons egalement une experience de laboratoire que nous avons montee et qui nous a permis jusqu'a present de mettre en evidence une extinction interferometrique monochromatique stable de plus de 10 3 . Enfin, nous discutons cette methode, appliquees a des telescopes au sol, comme precurseurs des futurs observatoires spatiaux.

The DARWIN observatory will include an interferometric instrument dedicated to the search for and spectral analysis of extrasolar planets. This instrument is based on the principle of Bracewell's interferometric coronograph or nulling interferometer, proposed in 1978. but at present never experimentally demonstrated in the thermal infrared with high extinctions.We have shown that high interferometric extinctions can only be obtained with 'classical' optical pieces if the beams are cleaned by optical filtering during the recombination. After a short reminder of the nulling interferometer, we present different techniques of optical filtering to perform it. Then, we present a laboratory experimental bench we have constructed. which allows us, at present, to exhibit a monochromatic stable interferometric extinction better than 10(3). Finally, we discuss this method, applied to ground-based telescopes. (C) 2001 Academie des sciences/Editions scientifiques et medicales Elsevier SAS.

Present projects of space interferometers dedicated to the detection and analysis of extrasolar planets (DARWIN in Europe, TPF in the United States) are based on the nulling interferometry concept. This concept has been proposed by Bracewell in 1978 but has never been demonstrated with high values of rejection, in the thermal infrared range, where the planet detection should be performed (6-18 mu m).We have thus built a two-beam laboratory interferometer to validate this concept in a monochromatic case (at 10 mu m). The keypoint of our interferometer is the use of optical filtering by pinhole and optical fibers to clean the interfering beams. We present in this paper the principle of the experimental setup, its realisation, and the first measurements of rejection it allowed. We also present the future developments of this interferometer.

Present projects of space interferometers dedicated to the detection and analysis of extrasolar planets (DARWIN in Europe, TPF in the United States) are based on the nulling interferometry concept (interferometric coronography). This concept has been proposed by Bracewell in 1979 but has never been demonstrated, with high values of rejection, in the thermal infrared range, where the planet detection should be per formed (6-18 mu m) We have thus built a two-beam laboratory interferometer to validate this concept in a monochromatic case. We present in this paper the principle of the experimental setup and its realization. We also present the first results obtained with this interferometer.

this paper, reported results are issued from a data set collected by theLymphoma Cooperative Group of the European Organisation for Research andTreatment of Cancer ( EORTC ) and provided by Dr. M. Henry-Amar

Surgery is the essential element of staging and treatment of malignant ovarian tumours. Regardless of the stage, it must include peritoneal cytology, hysterectomy with bilateral adnexectomy, omentectomy, pelvic and lumbo-aortic lymphadenectomy, appendicectomy and multiple peritoneal biopsies. In stage I tumours, in young women desiring a subsequent pregnancy, preservation of the uterus and contralateral ovary can be proposed. In stages II, III and IV, the therapeutic strategy consists of primary surgery and systematic chemotherapy (6 cycles). Radical surgery is essential in these cases, as the size of the residual tumour at the end of operation constitutes the major prognostic factor. To optimize the quality of tumour debulking, the maximum of visible carcinomatous nodules must be resected with, if necessary, gastrointestinal resections. The value of second-look surgery, after 6 cycles of chemotherapy, is currently controversial: it is only indicated in the context of randomized trials. Borderline malignant ovarian tumours have a good prognosis regardless of their stage. Surgery can very often be conservative, particularly in young women. Adjuvant chemotherapy has been shown to be effective in these rumours. Many studies are underway to define the value of new cytostatic molecules and "interval" surgery (intercalated between several courses of chemotherapy).

We report our institutional experience with the accuracy and usefulness of cervical amputations with frozen section evaluation of the endocervical margin in the management of preinvasive squamous epithelial lesions. Four hundred and fourteen consecutive patients, who underwent amputation of the cervix because of a preinvasive epithelial lesion, or discrepancy between cytologic and biopsy findings especially when colposcopic evaluation was unsatisfactory, had frozen section evaluation of the endocervical margin. Medical records were reviewed and pathologic findings were compared with those obtained on paraffin embedded sections. Frozen section analysis of the upper endocervical margin led to the diagnosis of a residual lesion in 90 (21.7%) cases. In 59 (14.2%) of these eases a further excision was performed during the same operative procedure leading to complete resection in 34 (8.2%) cases. In 403 (97.3%) cases the diagnosis based on the frozen section was corroborated by the permanent sections. For the diagnosis of insufficient cervical resection, the sensitivity and specificity of frozen sections were 93.8% and 99.7% respectively. We conclude that frozen section evaluation of the upper endocervical margin at the lime of cervical amputation is a reliable procedure that increases the rate of complete resection. The risks associated with additional anesthesia are then reduced, as are inconvenience to the patients and costs.

We report a retrospective series of 28 patients with Krukenberg tumors treated at the Gustave Roussy Institute from 1973 to 1990. Mean age of these women was 42 years. The patients were classed into two groups : depending on whether the ovarian metastasis (group 1) or the primary cancer (group 2) was discovered first. The primary tumor was identified in 20 cases (18 cases of linitis, 1 tumor of the cecum, 1 tumor of the appendix). The primary tumor remained unknown in 8 cases. Twenty-seven patients underwent radical total hysterectomy or bilateral adnexectomy. Gastrectomy was possible for 11 of the 18 cases of linitis ; hemicolectomy and appendectomy were performed for the cecal and appendicular tumors respectively. diagnosis of a primary tumor of the appendix was made after systematic appendectomy and of two Krukenberg tumors after systematic bilateral adnexectomy. In the first group of patients, both localizations were treated in 6 cases, one in 12 including 4 because gastrectomy was not initially possible and in 8 because the primary tumor was unknown. In the second group, the two localizations were treated in 7 cases, and one in 2 cases because gastrectomy was not possible. Surgery was not performed in one patient due to diffuse carcinosis. Bilateral ovarian metastases were seen in 26 out of the 28 cases and 26/28 had chemotherapy without any appreciable effect. Bone metastasis predominated (9 cases), followed by pleuropulmonary (5 cases) and liver (3 cases) metastasis. Overall median survival was 20 months ; 14 months in the first group and 29 months in the second. Appendectomy and exploration of the colon and the stomach were performed in all cases in which the Krukenberg tumor was discovered intraoperatively. An endosonographic exploration of the stomach is recommended if the primary tumor is not localized. Bilateral adnexectomy should always be performed in patients with linitis whatever the age. surgical treatment of the two localizations is not always sufficient for cure.

Between February 1985 and September 1992, 265 patients with various stages of endometrial carcinoma were enrolled in a multicenter retrospective study to analyze the prognostic value of peritoneal cytologic washings. Thirty-four (12.8%) patients had malignant results on peritoneal cytology. A statistically significant association (P = .002) was found between high histologic grade and positive cytology. On univariate analysis, prognostic variables affecting survival were myometrial invasion (P = .03), lymph node metastasis (P = .01), and malignant peritoneal cytology (P = .004). Malignant fluid cytology was not significantly associated (P = .26) with disease recurrence. Relapse occurred in 4 (11.8%) of 34 patients with positive peritoneal cytology and in 12 (5.2%) of 231 patients with negative peritoneal cytology. On multivariate analysis, lymph node involvement was the only prognostic factor that influenced outcome independently and adversely. On the basis of these findings, malignant peritoneal cytology does not appear to be an adverse and independent prognostic indicator in endometrial carcinoma.

The authors try to specify the place of Tomodensitometry in utero-ovarian cancers. The examination technique presents no particularities: at best, the interval and the depth of the cuts must be selected. In cervical cancers, the poor appreciation on TDM of adnexal and vaginal involvement renders this examination unsuitable for staging. On the contrary, it is absolutely necessary in order to make the diagnosis of recurrences. In cancers of the body of the uterus, almost always operated on, TDM presents very little interest for the initial work-up except for patients who are difficult to examine or are going to undergo irradiation. As for ovarian tumors, TDM may be useful to detect intra-hepatic metastases before the first operation, to monitor patients undergoing chemotherapy: peritoneal carcinosis is inconstantly detected and TDM cannot replace a second look.