Task-Based Image Quality Assessment Comparing Classical and Iterative Cone Beam CT Images on Halcyon.

Background: Despite the development of iterative reconstruction (IR) in diagnostic imaging, CBCT are generally reconstructed with filtered back projection (FBP) in radiotherapy. Varian medical systems, recently released with their latest Halcyon V2.0 accelerator, a new IR algorithm for CBCT reconstruction.

Assessment of combined use of ArcCheck detector and portal dosimetry for delivery quality assurance of head and neck and prostate volumetric-modulated arc therapy.

Purpose: To assess the efficiency of combined use of ArcCheck detector (AC) and portal dosimetry (PDIP) for delivery quality assurance of head and neck and prostate volumetric-modulated arc therapy.

Materials And Methods: Measurement processes were studied with the Gamma index method according to three analysis protocols. The detection sensitivity to technical errors of each individual or combined measurement processes was studied by inserting collimator, dose and MLC opening error into five head and neck and five prostate initial treatment plans.

Mixed modality treatment planning of accelerated partial breast irradiation: to improve complex dosimetry cases.

Background: Although 3D-conformal accelerated partial breast irradiation (APBI) is widely used, several questions still remain such as what are the optimal treatment planning modalities. Indeed, some patients may have an unfavorable anatomy and/or inadequate dosimetric constraints could be fulfilled ("complex cases"). In such cases, we wondered which treatment planning modality could be applied to achieve 3D-conformal APBI (2 mini-tangents and an "en face" electron field or non-coplanar photon multiple fields; or a mixed technique combining non-coplanar photon multiple fields with an "en face" electron beam).

[Debate about breast cancer: "Cons: Intraoperative radiotherapy"].

Early breast cancer incidence increases owing to mammography screening. Hypofractionated radiotherapy is more and more proposed in women with low local relapse risk breast cancer, especially accelerated partial breast irradiation. Various irradiation modalities have been reported: brachytherapy, intraoperative irradiation, 3D-conformal accelerated partial breast irradiation.

[Intensity modulation in breast radiotherapy: development of an innovative field-in-field technique at Institut Gustave-Roussy].

Purpose: To assess the potential dosimetric gain of presegmentation modulated radiotherapy (OAPS, DosiSoft™) of breast, compared to routine 3D conformal radiotherapy.

Patients And Methods: Twenty patients treated with conservative surgery for breast cancer (9 right and 11 left sided) with various breast volume (median 537 cm(3); range [100-1049 cm(3)]) have been selected. For each patient, we have delineated a breast volume and a compensation volume (target volumes), as well as organs at risk (lungs and heart).