Purpose. - In case of external breast radiotherapy, the usual treatment consists of two tangential beams homogeneously attenuated by a dynamic or physics wedge in order to obtain the most homogeneous dose distribution as possible. Depending of the shape and size of the breast volume, we may observe with this technique dose heterogeneity over 20% from the recommendation of the International Committee on Radiation Units and Measurements (95-107%). We propose to Study breast treatment, planning by compensating tissues thickness in order to decrease dose heterogeneity observed on the dose distribution for conventional treatment.Materials and methods. - We have segmented the initial tangential beams used for this kind of treatment into several smaller beams. Their shape was adapted to the distribution of the greys level on the DRR image. Therefore, we have compensated the thickness gradient and we have given the right dose to the right thickness group.Results. - Dose distribution performed with this method shows an improvement of the dose homogeneity in the three space dimensions and a decrease of the maximal dose between 5 and 10% over the ICRU recommendation.Conclusion. - This technique allows us to perform breast irradiation on a single photon energy linac even if the treated volume presents important thickness gradient. However, in case of large breast, this method is not able to reduce the overdosage at the entry of the volume due to inappropriate photon energy relative to the breast thickness. (C) 2009 Societe francaise de radiotherapie oncologique (SFRO). Published by Elsevier Masson SAS. All rights reserved.

PURPOSE:In case of external breast radiotherapy, the usual treatment consists of two tangential beams homogeneously attenuated by a dynamic or physics wedge in order to obtain the most homogeneous dose distribution as possible. Depending of the shape and size of the breast volume, we may observe with this technique dose heterogeneity over 20% from the recommendation of the International Committee on Radiation Units and Measurements (95-107%). We propose to study breast treatment planning by compensating tissues thickness in order to decrease dose heterogeneity observed on the dose distribution for conventional treatment.MATERIALS AND METHODS:We have segmented the initial tangential beams used for this kind of treatment into several smaller beams. Their shape was adapted to the distribution of the greys level on the DRR image. Therefore, we have compensated the thickness gradient and we have given the right dose to the right thickness group.RESULTS:Dose distribution performed with this method shows an improvement of the dose homogeneity in the three space dimensions and a decrease of the maximal dose between 5 and 10% over the ICRU recommendation.CONCLUSION:This technique allows us to perform breast irradiation on a single photon energy linac even if the treated volume presents important thickness gradient. However, in case of large breast, this method is not able to reduce the overdosage at the entry of the volume due to inappropriate photon energy relative to the breast thickness.

L’objectif était d’étudier trois plans de traitements dont un en modulation d’intensité lors de l’irradiation cérébrale d’une femme enceinte, afin de délivrer la dose la plus faible au fœtus. Le traitement envisagé était de 60 Gy dans le volume cible prévisionnel. Les mesures ont été réalisées à la partie supérieure et au milieu de l’utérus sur un fantôme RANDO associé à des plaques équivalent eau accolées. Le premier plan comportait quatre faisceaux délivrés selon une méthode conformationelle par un accélérateur Varian équipé d’un collimateur de 120 lames, le deuxième utilisait des faisceaux non coplanaires et le troisième testait une technique avec modulation d’intensité. Les trois plans utilisaient des photons de 6 MV. Avec la technique conformationelle, la dose mesurée à la partie supérieure de l’utérus était de 8,3 mGy et celle au centre de 6,3 mGy. Les doses reçues par le fœtus étaient supérieures avec la technique conformationelle tridimensionnelle et non coplanaire. Avec la modulation d’intensité, la dose à la partie supérieure de l’utérus était de 23,8 mGy et celle à la partie moyenne de 14,3 mGy. En raison de l’utilisation de lames et de faisceaux non coplanaires, la modulation d’intensité ne paraît donc a priori pas une technique adaptée pour le traitement d’une femme enceinte. Cependant, la dose reçue par le fœtus restant faible et inférieure à celle de 100 mGy recommandée par la Commission internationale de protection radiologique, il est possible d’envisager l’utilisation de cette technique pour une meilleure épargne des organes à risque chez la mère.The purpose was to assess three treatments planning techniques including one in intensity-modulated radiation therapy (IMRT) for cerebral irradiation of pregnant woman, in order to limit the dose delivered to the foetus. The treatment provided was 60 Gy to the planning target volume. Estimated foetal dose was measured using an anthropomorphic phantom, on the upper and middle part of the uterus. The first plan consisted in four beams in conformational technique delivered from a Varian accelerator with a 120 leaves collimator, the second one used non-coplanar fields and the third one assessed IMRT. With the conformational technique, the dose at the upper part of the uterus was 8.3 mGy and 6.3 mGy at the middle part. The dose delivered to the foetus was higher with the non-coplanar fields. In IMRT, the dose at the upper part of the uterus was 23.8 mGy and 14.3 mGy at the middle part. The three plans used 6 MV X-rays. Because of the use of leaves and non-coplanar fields, IMRT does not seem to be the optimal technique for the treatment of pregnant woman. However, the dose delivered to the foetus remains low and below the dose of 100 mGy recommended by the International Commission of Radiological Protection. It seems possible to consider the use of this technique for a better sparing of organs at risk for the mother.

Objectif de l'étude. – Évaluer l'impact de la fusion d'images de tomographie par émission de positons (TEP) au 18fluorodéoxyglucose ([18F]-FDG) et détection en coïncidence par gamma caméra et d'images de simulation virtuelle par tomodensitométrie pour la radiothérapie conformationnelle des cancers de l'œsophage.

Objectif de l'étude. – Évaluer dans une série rétrospective l'impact du recalage d'images de tomographie par émission de positons (TEP) au 18fluorodéoxyglucose ([18F]-FDG) et détection en coïncidence (TEDC) par gamma-caméra et d'images de simulation virtuelle par tomodensitométrie pour la radiothérapie conformationnelle des cancers bronchiques non à petites cellules.

Purpose: To study the impact of fused F-18-fluoro-deoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and computed tomography (CT) images on conformal radiotherapy planning for esophageal carcinoma patients.Methods and Materials: Thirty-four esophageal carcinoma patients were referred for concomitant radiotherapy and chemotherapy with radical intent. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same treatment position. PET images were coregistered using five fiducial markers. Target delineation was initially performed on CT images, and the corresponding PET data were subsequently used as an overlay to CT data to define the target volume.Results: F-18-fluorodeOXY-D-glucose-PET identified previously undetected distant metastatic disease in 2 patients, making them ineligible for curative conformal radiotherapy. The gross tumor volume (GTV) was decreased by CT and FDG image fusion in 12 patients (35%) and increased in 7 patients (21%). The GTV reduction was :25% in 4 patients owing to a reduction in the length of the esophageal tumor. The GTV increase was >= 25% with FDG-PET in 2 patients owing to the detection of occult mediastinal lymph node involvement in 1 patient and an increased length of the esophageal tumor in 1 patient. Modifications of the GTV affected the planning treatment volume in 18 patients. Modifications of the delineation of the GTV and displacement of the isocenter of the planning treatment volume by FDG-PET also affected the percentage of total lung volume receiving > 20 Gy in 25 patients (74%), with a dose reduction in 12 patients and dose increase in 13.Conclusion: In our study, CT and FDG-PET image fusion appeared to have an impact on treatment planning and management of esophageal carcinoma. The affect on treatment outcome remains to be demonstrated. (c) 2005 Elsevier Inc.

UNLABELLED:To report a retrospective study concerning the impact of fused 18F-fluorodeoxy-D-glucose (FDG)-hybrid positron emission tomography (PET) and computed tomography (CT) images on three-dimensional conformal radiation therapy (3D-CRT) planning for patients with non-small-cell lung cancer (NSCLC).PATIENTS AND METHODS:One hundred and one patients consecutively treated for stages I-III NSCLC were studied. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same radiation treatment position. Images were coregistered using five fiducial markers. Target volume delineation was initially performed on the CT images and the corresponding FDG-PET data were subsequently used as an overlay to the CT data to define target volume.RESULTS:FDG-PET identified previously undetected distant metastatic disease in 8 patients making them ineligible for curative CRT (one patient presented some positive uptakes corresponding to concomitant pulmonary tuberculosis). Another patient was ineligible for curative treatment because fused CT/PET images demonstrated excessively extensive intrathoracic disease. The gross tumor volume (GTV) was decreased by CT/PET image fusion in 21 patients (23%) and was increased in 24 patients (26%). The GTV reduction was > or = 25% in 7 patients because CT/PET image fusion reduced pulmonary GTV in 6 patients (3 patients with atelectasis) and mediastinal nodal GTV in 1 patient. The GTV increase was > or = 25% in 14 patients due to an increase of the pulmonary GTV in 11 patients (4 patients with atelectasis) and detection of occult mediastinal lymph node involvement in 3 patients. Among 81 patients receiving a total dose > or = 60 Gy at ICRU point, after CT/PET image fusion, the percentage of total lung volume receiving more than 20 Gy (VL20) increased in 15 cases and decreased in 22 cases. The percentage of total heart volume receiving more than 36 Gy increased in 8 patients and decreased in 14 patients. The spinal cord volume receiving at least 45 Gy (2 patients) decreased. After multivariate analysis, one single independent factor made significant effect of FDG/PET on the modification of the size of the GTV: tumor with atelectasis (P = 0.0001). Conclusion. - Our study confirms that integrated hybrid PET/CT in the treatment position and coregistered images have an impact on treatment planning and management of patients with NSCLC. FDG images using dedicated PET scanners with modern image fusion techniques and respiration-gated acquisition protocols could improve CT/PET image coregistration. However, prospective studies with histological correlation are necessary and the impact on treatment outcome remains to be demonstrated.

Purpose: To report a retrospective study concerning the impact of fused F-18-fluoro-deoxy-D-glucose (FDG)hybrid positron emission tomography (PET) and CT images on three-dimensional conformal radiotherapy planning for patients with non-small-cell lung cancer.Methods and Materials: A total of 101 patients consecutively treated for Stage I-III non-small-cell lung cancer were studied. Each patient underwent CT and FDG-hybrid PET for simulation treatment in the same treatment position. Images were coregistered using five fiducial markers. Target volume delineation was initially performed on the CT images, and the corresponding FDG-PET data were subsequently used as an overlay to the CT data to define the target volume.Results: F-18-fluoro-deoxy-D-glucose-PET identified previously undetected distant metastatic disease in 8 patients, making them ineligible for curative conformal radiotherapy (1 patient presented with some positive uptake corresponding to concomitant pulmonary tuberculosis). Another patient was ineligible for curative treatment because the fused PET-CT images demonstrated excessively extensive intrathoracic disease. The gross tumor volume (GTV) was decreased by CT-PET image fusion in 21 patients (23%) and was increased in 24 patients (26%). The GTV reduction was >= 25% in 7 patients because CT-PET image fusion reduced the pulmonary GTV in 6 patients (3 patients with atelectasis) and the mediastinal nodal GTV in 1 patient. The GTV increase was >= 25% in 14 patients owing to an increase in the pulmonary GTV in 11 patients (4 patients with atelectasis) and detection of occult mediastinal lymph node involvement in 3 patients. Of 81 patients receiving a total dose of; >= 60 Gy at the International Commission on Radiation Units and Measurements point, after CT-PET image fusion, the percentage of total lung volume receiving > 20 Gy increased in 15 cases and decreased in 22. The percentage of total heart volume receiving > 36 Gy increased in 8 patients and decreased in 14. The spinal cord volume receiving at least 45 Gy (2 patients) decreased. Multivariate analysis showed that tumor with atelectasis was the single independent factor that resulted in a significant effect on the modification of the size of the GTV by FDG-PET: tumor with atelectasis (with vs. without atelectasis, p = 0.0001).Conclusion: The results of our study have confirmed that integrated hybrid PET/CT in the treatment position and coregistered images have an impact on treatment planning and management of non-small-cell lung cancer. However, FDG images using dedicated PET scanners and respiration-gated acquisition protocols could improve the PET-CT image coregistration. Furthermore, the impact on treatment outcome remains to be demonstrated. (c) 2005 Elsevier Inc.

Impact de la fusion d'images de TEP au [18F]-FDG avec détection de coïncidence par gamma caméra et d'images de simulation virtuelle par tomodensitométrie pour la radiothérapie conformationnelle tridimensionnelle des carcinomes bronchiques non à petites cellules E. Deniaud-Alexandre a, E. Touboul a, D. Lerouge a, J.N. Foulquier a, Y. Petegnief b, B. Grés a, H. El Balaa a, K. Keraudy a, K. Kerrou b, J.N. Talbot b a Service d'oncologie–radiothérapie, hôpital Tenon APHP, 75020 Paris, France b Service de médecine nucléaire, hôpital Tenon APHP, 75020 Paris, France

In addition to classical HDR, PDR or LDR brachytherapy, new techniques such as transperineal radioactive implantations of the prostate via template guidance, or vascular brachytherapy for the prevention of restenosis, are becoming increasingly popular. At the same time they are introduced in a department, a quality assurance program must be implemented both to minimize the risks of treatment misadministrations and to prove respect to legal liability. The authors try to point out the necessary equipments and the particularities of Q.A. programs which must cover all the steps of the treatment. They consider successively prostate and vascular brachytherapy, making for each of them, a quick review of the most current techniques (including associated accessories and imaging devices), showing the particularities of adapted computerized treatment planning systems and the characteristics of radioactive sources usually used (photon sources for prostate such as 192 Ir for temporary implants and 125I and 103 Pd for permanent implants, 192 Ir or bêta sources for vessels). Particular detectors and methods to be employed to perform quality controls of equipments and sources, or in vivo measurements, are also presented. Lastly the guidelines and recommendations for “good practice and quality assurance” concerning these particular techniques and published by different international organizations, or which are in the process of development, are summarized. It will be noted that volume definitions, dose prescription and reporting, dose planning, dosimetry, staffing and responsabilities,etc, are or should be included in a complete quality assurance program.

Volvulus of the pelvic colon has a high prevalence in black Africa with two maxima observed in patients after 60 or between 20 and 40 when it is observed only in the over 60 caucasian group. In young african adults the clinical pattern presents always the acute type. Diagnosis is easy, but often made too late because of delayed report to the hospital. Various surgical procedures are discussed. Observed death rate has been 22 p. 100.