Jean-François Daisne

Tri-dimensional automatic segmentation of PET volumes based on measured source-to-background ratios: influence of reconstruction algorithms.

A method for automatic volume segmentation of functional imaging based on a relationship between source-to-background ratio and the iso-activity level to be used is described. Such method, which has been established with radioactive spheres in a phantom, is independent of the a priori knowledge of the lesion of interest and is valid for small (>2 ml) and/or poorly contrasted (S/B>1.5) lesions. Accuracy varies slightly with the image reconstruction algorithm used.

Radiothérapie en conditions stéréotaxiques des métastases cérébrales

Stereotactic radiosurgery is now well implanted in the radiotherapy treatment tools of brain metastasis. The dose can be delivered in one or multiple sessions. Results seem equivalent. CT scan and MRI imaging are required to delineate and calculate dosimetry. Doses are variable according to the size of the metastases, localization, pathology or equipment. Stabilization or reduction of tumour size is the rules after stereotactic treatment. Impact in terms of overall survival is more difficult to apprehend because of the general context of the disease. Many questions remain unresolved, such as the usefulness of whole brain irradiation, adaptation of the treatment schedule to tumour pathophysiology, role of stereotactic treatment after surgery of metastases, etc.

Sélection et délimitation des volumes–cibles anatomocliniques ganglionnaires dans les tumeurs de la sphère cervico-maxillo-faciale

This article reviews all clinical and pathological data available in the literature supporting the concept of selectivity in the neck nodes to be included in the Clinical Target Volume for head and neck squamous cell carcinoma. Using the terminology of neck node levels and the guidelines for the surgical delineation of these levels proposed by the Committee for Head and Neck Surgery and Oncology of the American Academy for Otolaryngology-Head and Neck Surgery, recommendations are proposed for both the selection and the delineation of lymph node target volumes.

Recurrence patterns after a decreased dose of 40 Gy to the elective treated neck in head and neck cancer

PURPOSE To investigate the patterns of regional recurrences with emphasis on recurrences in the electively irradiated lymph node regions after dose de-escalation to 40Gy (EQD2Gy) in head and neck cancer. METHODS AND MATERIALS Two hundred thirty-three patients treated with radio(chemo)therapy using 40Gy (EQD2Gy) to the elective lymph node regions were included. All regional recurrences were reconstructed and projected on the initial radiotherapy planning Computed Tomography studies to identify the localization of recurrence. Furthermore, patient and treatment characteristics were correlated with the regional recurrences to identify risk factors. RESULTS The median follow-up in our study was 26months. Overall- and disease-specific survival at 2years were 71.2% (95% CI 65.3-77.1) and 64.2% (95% CI 59.2-69.3), respectively. Local, regional and distant control at 2years was 84.1% (95% CI 79.1-89.2), 89.2% (95% CI 84.3-94.1) and 83.2% (95% CI 76.3-90.1), respectively. Twenty-eight patients experienced a regional recurrence. Fourteen of these patients had a recurrence within the high dose volume (14 of 28). Nine had a recurrence in the electively irradiated lymph node regions (9 of 28) and 5 recurrences occurred outside the target volume. The actuarial rate of recurrence in the electively irradiated lymph node regions was 3.9% (95% CI 1.8-6.0) at 2years. No significant associations could be observed between recurrence in electively irradiated lymph node regions and age, gender, tumor site, stage, or the presence of human papillomavirus in oropharyngeal cancers. CONCLUSIONS The actuarial rate of recurrence in the electively irradiated lymph node regions was 3.9% (95% CI 1.8-6.0) at 2years. This incidence is comparable to recurrence rates after standard dose of 50Gy, suggesting that lower doses to the elective neck do not result in higher regional recurrences.

Automatic Sentinel Lymph Node Localization in Head and Neck Cancer Using a Coupled Shape Model Algorithm

The localization and analysis of the sentinel lymph node for patients diagnosed with cancer, has significant influence on the prognosis, outcome and treatment of the disease. We present a fully automatic approach to localize the sentinel lymph node and additional active nodes and determine their lymph node level on SPECT-CT data. This is a crucial prerequisite for the planning of radiation therapy or a surgical neck dissection. Our approach was evaluated on 17 lymph nodes. The detection rate of the lymph nodes was 94%; and 88% of the lymph nodes were correctly assigned to their corresponding lymph node level. The proposed algorithm targets a very important topic in clinical practice. The first results are already very promising. The next step has to be the evaluation on a larger data set.