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I Rousselle

Publications and source records attributed to I Rousselle.

4 recordsLinked to original sources
PubMed1997

[Determination of target volume for dosimetric planning in stereotactic radiosurgery].

Stereotactic radiosurgery needs an accurate determination of the target volumes to be irradiated and of sensitive volumes to be spared: position, external boundaries, internal volume. These parameters can be obtained by using either projection imaging (radiographs, digital angiography), or tomographic imaging (magnetic resonance imaging, computerized tomography). The authors describe the methods used in these different imaging modalities and the problems encountered in target determination. Methods of validations are described. Results obtained on phantoms and on actual target volume are given and discussed.

Humans↗
PubMedDate not supplied

[Progress in dosage optimization for stereotactic radiosurgery].

Stereotactic radiosurgery is a technique for treatment of intracranial lesions requiring high precision in all steps--from image acquisition to final irradiation. One of most difficult steps is the treatment planning phase, consisting of determination of irradiation parameters sufficient to cover the target volume by avoiding sensitive volumes. A manual and empirical definition can be very long and difficult, especially in the case of complex target volumes situated in sensitive zones. As in conventional radiotherapy, stereotactic radiosurgery has taken advantages from dosimetric optimization. The question is: "What is the configuration of irradiation parameters used in order to obtain the treatment plan by satisfying defined constraints?". The purpose of this article is to summarize optimization methods used in radiosurgery and to describe the technical alternatives proposed for this treatment as well as the possibilities of plan evaluation between different techniques. This purpose will be illustrated by the optimization methodology used in the Center Oscar Lambret of Lille, France for the radiosurgical treatment with linear accelerator.

Algorithms↗
PubMedDate not supplied

[Dosimetric quality control in stereotactic radiotherapy with the aid of radiosensitivity].

Typical dosimeters used in stereotactic radiation therapy, such as ionization chambers, films, and thermoluminescent diodes, allow basic physical measurements. They are, however, neither well suited to discern small target volumes with high dose gradient, nor suitable for three-dimensional (3D) dose measurements. Gel dosimetry is becoming more and more interesting, owing to magnetic resonance imaging (MRI). It permits isocenter position planning verification of accuracy and the precision of the 3D dose mapping in the brain (when irradiated in realistic conditions), especially when several different targets are concerned. Many authors have assessed stereotactic radiation therapy quality control using different gels, and different irradiation procedures. This paper consists of the review of these different methods to assess quality control. Gel dosimetry cannot provide absolute dose measurements. However, gels can be used to check the 3D dose mapping with a high degree of detail. In our experiment, the difference between the stereotactic frame center and the isocenter is about 1 mm. The difference between the theoretical isodoses obtained by the treatment planning system and the experimental isodoses obtained by the MRI gray level calibration is also about 1 mm, the order of magnitude of the MRI pixel size.

Gels↗