Collimator scatter factor: Monte Carlo and in-air measurements approaches.

Background: Linac output as a function of field sizes has a phantom and a head scatter component. This last term can be measured in-air with appropriate build-up ensuring a complete electron equilibrium and the absence of the contaminant electrons. Equilibrium conditions could be achieved using a build-up cap or a mini-phantom.

Evaluation of target dose inhomogeneity in breast cancer treatment due to tissue elemental differences.

Background: Monte Carlo simulations were run to estimate the dose variations generated by thedifference arising from the chemical composition of the tissues.

Methods: CT datasets of five breast cancer patients were selected. Mammary gland was delineated as clinical target volume CTV, as well as CTV_lob and CTV_fat, being the lobular and fat fractions of the entire mammary gland.

Dosimetric evaluation of modern radiation therapy techniques for left breast in deep-inspiration breath-hold.

Purpose: The dosimetric differences between four radiation therapy techniques for left sided whole breast irradiation were evaluated side by side in the same patient population.

Methods: Radiotherapy treatment plans were retrospectively created with Accuray TomoDirect (TD), Elekta Volumetric Modulated Arc Therapy (E-VMAT), Varian RapidArc (RA) and Field-in-field (FinF) technique for 20 patients, who had received left breast irradiation during deep-inspiration breath-hold. Dose characteristics of planning target volume and organs at risk were compared.

Hypofractionated volumetric modulated arc therapy in ductal carcinoma in situ: toxicity and cosmetic outcome from a prospective series.

Objective: Hypofractionated radiotherapy in early stage breast cancer is an effective adjuvant treatment, but there is a lack of randomized data for patients with ductal carcinoma in situ (DCIS). The aim of this study is the evaluation of skin toxicity and cosmesis, and early clinical outcome of DCIS patients enrolled in an institutional Phase II trial of hypofractionated breast irradiation.

Methods: 137 DCIS patients were enrolled in the trial.

Critical Appraisal of the Risk of Secondary Cancer Induction From Breast Radiation Therapy With Volumetric Modulated Arc Therapy Relative to 3D Conformal Therapy.

Purpose: To evaluate the excess absolute risk (EAR) comparing volumetric modulated arc therapy (VMAT) and 3-dimensional (3D) conformal radiation therapy (CRT) in breast cancer radiation therapy treatment.

Methods And Materials: Two VMAT arrangements (VMAT_tang and VMAT_full, i.e.

On the gEUD biological optimization objective for organs at risk in Photon Optimizer of Eclipse treatment planning system.

Inverse planning optimization using biologically based objectives is becoming part of the intensity modulated optimization process. The performances and efficacy of the biologically based gEUD (generalized Equivalent Uniform Dose) objective implemented in the Photon Optimizer (PO) of Varian Eclipse treatment planning system have been here analyzed. gEUD is associated with the parameter a that accounts for the seriality of a structure, being higher for more serial organs.

Stereotactic/hypofractionated body radiation therapy as an effective treatment for lymph node metastases from colorectal cancer: an institutional retrospective analysis.

Objective: The colorectal cancer (CRC) might present loco-regional recurrence, including lymph-node metastasis. Stereotactic body radiotherapy (SBRT) is a non-invasive and well-tolerated ablative treatment. Aim of the present study is to evaluate efficacy and toxicity of SBRT with volumetric modulated arc therapy (VMAT) in this setting.

RapidPlan head and neck model: the objectives and possible clinical benefit.

Background: To evaluate a knowledge based planning model for RapidPlan (RP) generated for advanced head and neck cancer (HNC) patient treatments, as well its ability to possibly improve the clinical plan quality. The stability of the model was assessed also for a different beam geometry, different dose fractionation and different management of bilateral structures (parotids).

Methods: Dosimetric and geometric data from plans of 83 patients presenting HNC were selected for the model training.

Moderate hypofractionated radiotherapy with volumetric modulated arc therapy and simultaneous integrated boost for pelvic irradiation in prostate cancer.

Purpose: The optimal treatment for unfavourable intermediate/high-risk prostate cancer is still debated. In the present study, the pattern of toxicity and early clinical outcome of patients with localized prostate cancer was analyzed.

Methods: A cohort of 90 patients treated on pelvic lymph nodes from 2010 to 2015 was selected.

Dose calculation algorithm accuracy for small fields in non-homogeneous media: The lung SBRT case.

This review addresses the theme of dose calculation accuracy in the case of the stereotactic treatment of lung lesions. Based on the classical categories of type "a", "b" and "c" algorithms (according to their degree of complexity in the management of charged particle transport), a summary of findings from literature is reported. Two main critical areas have been identified: the use of small fields and the presence of low density medium.

Dosimetric trade-offs in breast treatment with VMAT technique.

Objective: Breast planning with volumetric modulated arc therapy (VMAT) has been explored, especially for left-sided breast treatments, with the primary intent of lowering the heart dose and improving target dose homogeneity. As a trade-off, larger healthy tissue volumes would receive low dose levels, with the potential risk of increasing late toxicities and secondary cancer induction, although no clinical data are available today to confirm the risk level. The scope of this work is to explore the dosimetric trade-offs using two different VMAT plans.

Evaluation of the dose calculation accuracy for small fields defined by jaw or MLC for AAA and Acuros XB algorithms.

Purpose: Small field measurements are challenging, due to the physical characteristics coming from the lack of charged particle equilibrium, the partial occlusion of the finite radiation source, and to the detector response. These characteristics can be modeled in the dose calculations in the treatment planning systems. Aim of the present work is to evaluate the MU calculation accuracy for small fields, defined by jaw or MLC, for anisotropic analytical algorithm (AAA) and Acuros XB algorithms, relative to output measurements on the beam central axis.

Phase II trial of hypofractionated VMAT-based treatment for early stage breast cancer: 2-year toxicity and clinical results.

Background: To report toxicity and early clinical outcomes of hypofractionated simultaneous integrated boost (SIB) approach with Volumetric Modulated Arc Therapy (VMAT) as adjuvant treatment after breast-conserving surgery.

Methods: Patients presenting early-stage breast cancer were enrolled in a phase II trial.

Eligibility Criteria: age > 18 years old, invasive cancer or ductal carcinoma in situ (DCIS), Stage I-II (T < 3 cm and N ≤ 3), breast-conserving surgery without oncoplastic reconstruction.