[Pulse Dose Rate brachytherapy: optimization and place of imaging]. / La curiethérapie de débit pulsé: optimisation et place de l'imagerie.

Pulse Dose Rate (PDR) brachytherapy presents the potential radiobiological advantages of low dose rate and the technical and radiation protection advantages of high dose rate remote afterloading technology. The different algorithms provided by the treatment planning systems allow dose rate and isodose shape optimization regarding the volumes defined by the radiologist and the radiation oncologist. The contribution of imaging together with these new optimization tools should improve brachytherapy practice and the therapeutic ratio. These new evolutions of brachytherapy will be presented here.

[Partial breast irradiation: high dose rate peroperative brachytherapy technique using the MammoSite]. / Irradiation partielle du sein: technique de curiethérapie de haut débit de dose après l'implantation peropératoire du dispositif MammoSite.

In the conservative management of breast cancer, radiation therapy delivering 45 to 50 Gy to the whole breast, in 4.5 to 5 weeks, followed by a booster dose of 10 to 20 Gy is the standard of care. Based on the numerous studies which have reported that the local recurrences occurs within and surrounding the primary tumor site and in order to decrease the treatment duration and its morbidity, partial breast irradiation using several techniques has been developed. Partial irradiation may be considered as an alternative local adjuvant treatment for selected patients with favorable prognostic factors. Using external beam radiation therapy, the 3D-conformal technique is appropriate to deliver the whole dose to a limited volume. In UK, an intraoperative technique using a miniature beam of low energy of x-ray (50 Kv) has been developed (Targit). Milan's team have developed an intraoperative electrons beam radiotherapy using a dedicated linear accelerator in the operative room. In USA and Canada the MammoSite has been advised for clinical use in per-operative brachytherapy of the breast. These two last techniques are currently compared in phase III randomised studies to the standard whole breast irradiation followed by a tumour bed booster dose. In this review we will focus on the MammoSite technique and will describe the per-operative implantation procedure, radiological controls ad dosimetric aspects.

[In vivo dosimetry and radiation therapy of breast cancer]. / Dosimétrie in vivo et radiothérapie des cancers du sein.

INTRODUCTION: Verification of absorbed dose in target volume is a key factor for quality assurance in radiotherapy. In vivo measurements allow evaluation of the variations in dose with time and variations between measured doses and calculated doses by TPS. The aim of this work were to evaluate reproducibility of patient positioning and to compare calculated doses by 2 different TPS. PATIENTS AND METHODS: Twenty patients were divided in 2 groups according to the thickness of their breast (mean SSD = 92.9 cm). In vivo measurement was performed within the first two sessions. RESULTS: Reproducibility of SSD evaluation was made on 12 beams between 2 fractions. With a tolerance margin of 0.5 cm, positioning errors were present in 33% (4/12). The 2 TPS were in agreement in 75% (30/40). CONCLUSION: In vivo dosimetry can be a very interesting tool to assess patients positioning variations and TPS dose calculation.