Statistical Modeling of the Eye for Multimodal Treatment Planning for External Beam Radiation Therapy of Intraocular Tumors.

PURPOSE: Ocular anatomy and radiation-associated toxicities provide unique challenges for external beam radiation therapy. For treatment planning, precise modeling of organs at risk and tumor volume are crucial. Development of a precise eye model and automatic adaptation of this model to patients' anatomy remain problematic because of organ shape variability. This work introduces the application of a 3-dimensional (3D) statistical shape model as a novel method for precise eye modeling for external beam radiation therapy of intraocular tumors. METHODS AND MATERIALS: Manual and automatic segmentations were compared for 17 patients, based on head computed tomography (CT) volume scans. A 3D statistical shape model of the cornea, lens, and sclera as well as of the optic disc position was developed. Furthermore, an active shape model was built to enable automatic fitting of the eye model to CT slice stacks. Cross-validation was performed based on leave-one-out tests for all training shapes by measuring dice coefficients and mean segmentation errors between automatic segmentation and manual segmentation by an expert. RESULTS: Cross-validation revealed a dice similarity of 95% ± 2% for the sclera and cornea and 91% ± 2% for the lens. Overall, mean segmentation error was found to be 0.3 ± 0.1 mm. Average segmentation time was 14 ± 2 s on a standard personal computer. CONCLUSIONS: Our results show that the solution presented outperforms state-of-the-art methods in terms of accuracy, reliability, and robustness. Moreover, the eye model shape as well as its variability is learned from a training set rather than by making shape assumptions (eg, as with the spherical or elliptical model). Therefore, the model appears to be capable of modeling nonspherically and nonelliptically shaped eyes.

La variabilité chirurgicale en Suisse : différences intercantonales observées pour trois interventions

En Suisse, la variabilité géographique de la consommation de soins chirurgicaux est un domaine encore inexploré. Ce rapport examine de manière descriptive trois interventions chirurgicales réalisées en Suisse entre 2003 et 2005 : la prothèse partielle ou totale de hanche, la prothèse de genou et la cure de hernie discale. Il se concentre sur les caractéristiques démographiques des patients opérés, leur diagnostic et les différences des taux d'intervention selon les cantons. Les résultats sont présentés sous forme de taux bruts, de taux standardisés et de cartes géographiques de distribution.

Loulied Elli Ghrek / Edmond Natan Yafil et Pepino, auteurs. Ell Mra Elli Herbet Aâla Radjelha / Edmond Natan Yafil, auteur

[Traditions. Afrique du Nord. Algérie]

El Mra Elli Aâmret Fel Ghenaïa ; Meaâehrot El Djirana / Edmond Natan Yafil et Pépino, auteurs

[Traditions. Afrique du Nord. Algérie]

Haïta / Mahlema Brika, chant. Sefa / Mahlema Zohra El Marrakechia, voix

[Traditions. Afrique du Nord. Algérie]

Abisollan Fkiraoun Laman ; Ouahed Loucham / Rais Abdallah Enair, chant [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

Guedmioua ; Tifelt / Raïs Mohamed Mouzi, chant [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

Manaoudchi M'hlic ; Nahoua Ghouziel / Mira El Marrakchia, chant [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

Tiznit ; Allouch / Abouch Tamassit, chant [acc. voc. et perc.]

[Traditions. Afrique du Nord. Maroc]

Bsit Drad Dil ; Bsit Drad Dil (suite) / Benhaïm et Melul, duo voc. [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

Nodé : Chant hébraïque ; Nodé (suite) / Troupe Hadida et Bohbot

[Traditions. Afrique du Nord. Maroc]

Hozrimi El Hay ; Hozrimi El Hay (suite) / Troupe Hadida et Bohbot

[Traditions. Afrique du Nord. Maroc]

Yafim Halelot Bikhnahan ; Rahom Bakh Yaghil / Troupe Hadida et Bohbot

[Traditions. Afrique du Nord. Maroc]

Dialt Frouga ; Gmasa / Moulay Ahmed, chant [acc. instr.]

[Traditions. Afrique du Nord. Maroc]

Ksida Dialt El M'zouda ; Ksida Dialt Haha / Moulay Ahmed, chant [acc. instr.]

[Traditions. Afrique du Nord. Maroc]