Using density computed tomography images for photon dose calculations in radiation oncology: A patient study.

Background And Purpose: Conventional workflows for dose calculations require conversions between Hounsfield Units (HU) and the mass or electron density for Computed Tomography (CT) images in the Treatment Planning System (TPS). These conversions are scanner- and mostly kVp-dependent. A density representation or reconstruction at the CT level can potentially simplify the workflow.

Efficiency and Accuracy Evaluation of Multiple Diffusion-Weighted MRI Techniques Across Different Scanners.

Background: The choice between different diffusion-weighted imaging (DWI) techniques is difficult as each comes with tradeoffs for efficient clinical routine imaging and apparent diffusion coefficient (ADC) accuracy.

Purpose: To quantify signal-to-noise-ratio (SNR) efficiency, ADC accuracy, artifacts, and distortions for different DWI acquisition techniques, coils, and scanners.

Study Type: Phantom, in vivo intraindividual biomarker accuracy between DWI techniques and independent ratings.

Evaluation of surface image guidance and Deep inspiration Breath Hold technique for breast treatments with Halcyon.

Purpose: To evaluate the accuracy/agreement of a three-camera Catalyst Surface Guided Radiation Therapy (SGRT) system on a closed-gantry Halcyon for Free-Breathing (FB) and Deep Inspiration Breath Hold (DIBH) breast-only treatments.

Methods: The SGRT positioning agreement with Halcyon couch and cone-beam computed tomography (CBCT) was evaluated on phantom and by evaluation of 2401 FB and 855 DIBH breast-only treatment sessions. The DIBH agreement was evaluated using a programmable moving support.

Stereotactic Radioablation for Ventricular Tachycardia in the Setting of Electrical Storm.

Background: Stereotactic body radiotherapy (SBRT) has been reported as a safe and efficient therapy for treating refractory ventricular tachycardia (VT) despite optimal medical treatment and catheter ablation. However, data on the use of SBRT in patients with electrical storm (ES) is lacking. The aim of this study was to assess the clinical outcomes associated with SBRT in the context of ES.

News in magnetic resonance imaging use for radiation oncology.

The purpose of this article is to give a summary of the progress of magnetic resonance imaging (MRI) in radiotherapy. MRI is an important imaging modality for treatment planning in radiotherapy. However, the registration step with the simulation scanner can be a source of errors, motivating the implementation of all-MRI simulation methods and new accelerators coupled with on-board MRI.

Comparison of compressed sensing and controlled aliasing in parallel imaging acceleration for 3D magnetic resonance imaging for radiotherapy preparation.

Magnetic resonance imaging (MRI) for radiotherapy is often based on 3D acquisitions, but suffers from low signal-to-noise ratio due to immobilization device and flexible coil use. The aim of this study was to investigate if Compressed Sensing (CS) improves image quality for 3D Turbo Spin Echo acquisitions compared with Controlled Aliasing k-space-based parallel imaging in equivalent acquisition time for intracranial T1, T2-Fluid-Attenuated Inversion Recovery (FLAIR) and pelvic T2 imaging. Qualitative ratings suffered from large inter-rater variability.

Evaluation of an ultrasound bladder scanner in supine and standing position.

Purpose: This study examined the performance of a bladder volume measuring device, the BladderScan (BS) BVI9400. The use of the BS offers the possibility of assessing the bladder volume before positioning the patient and performing the daily image-guided radiotherapy procedure. Patients often cannot lie down before entering the treatment vault.

Technical note: Unexpected external markers artifact in 3D k-space based parallel imaging turbo spin-echo magnetic resonance imaging.

Purpose: MRI for radiotherapy planning requires spatial referencing using immobilization devices and markers. Clinical images of a difficult-to-interpret artifact are presented, resembling a metastasis, which occurs when combining CAIPIRINHA k-space-based parallel imaging (PI), 3D distortion correction, and external markers.

Methods: A 3D variable flip angle Turbo Spin Echo sequence was used on a 1.

[Radiotherapy for patients with early-stage glottic squamous cell carcinoma of the larynx: Interest of hypofractionation?].

Hypofractionated radiotherapy of early-stage squamous cell carcinoma of the glottic larynx is a promising treatment option. This can be divided into radiotherapy with moderate hypofractionation (up to 2.5Gy per fraction), more intense hypofractionation (between 2.

Correlation between toxicity and dosimetric parameters for adjuvant intensity modulated radiation therapy of breast cancer: a prospective study.

Orcid: 0000-0001-6019-7309. In the treatment of breast cancer, intensity-modulated radiation therapy (IMRT) reportedly reduces the high-dose irradiation of at-risk organs and decreases the frequency of adverse events (AEs). Comparisons with conventional radiotherapy have shown that IMRT is associated with lower frequencies of acute and late-onset AEs.

Prospective Study of Intensity-Modulated Radiation Therapy for Locally Advanced Breast Cancer.

The objective of this study was to evaluate the acute and medium-term toxicities, the quality of life, and aesthetic results of patients with breast cancer (BC) treated with tomotherapy. This was a prospective study, including patients with BC treated by tomotherapy. Radiation therapy delivered 50 Gy in 25 fractions to the breast or chest wall and to lymph node areas, with a simultaneous integrated boost at a dose of 60 Gy at the tumor bed in cases of breast conservative surgery.

Integration of the M6 Cyberknife in the Moderato Monte Carlo platform and prediction of beam parameters using machine learning.

Purpose: This work describes the integration of the M6 Cyberknife in the Moderato Monte Carlo platform, and introduces a machine learning method to accelerate the modelling of a linac.

Methods: The MLC-equipped M6 Cyberknife was modelled and integrated in Moderato, our in-house platform offering independent verification of radiotherapy dose distributions. The model was validated by comparing TPS dose distributions with Moderato and by film measurements.

[Radiotherapy treatment planning of prostate cancer using magnetic resonance imaging].

Purpose: Magnetic resonance imaging (MRI) plays an increasing role in radiotherapy dose planning. Indeed, MRI offers superior soft tissue contrast compared to computerized tomography (CT) and therefore could provide a better delineation of target volumes and organs at risk than CT for radiotherapy. Furthermore, an MRI-only radiotherapy workflow would suppress registration errors inherent to the registration of MRI with CT.

[Left-sided breast cancer locoregional radiation therapy with rotational intensity-modulated irradiation and deep inspiration breath hold: Dosimetric comparison].

Purpose: Adjuvant left-sided breast cancer locoregional radiotherapy can be accounted for long-term cardiac toxicity. The deep inspiration breath hold techniques can reduce cardiac doses. Only a few studies have investigated rotational intensity-modulated radiotherapy with deep inspiration breath hold.

Intensity-modulated radiation therapy with simultaneous integrated boost for locally advanced breast cancer: a prospective study on toxicity and quality of life.

Radiotherapy after breast conserving surgery and mastectomy with node positive disease has been shown to reduce risk of recurrence and mortality in the treatment of breast cancer. Intensity-modulated radiation therapy (IMRT) after conservative surgery offers several advantages over conventional RT including improved acute and late toxicity and quality of life (QoL). We undertook this study to prospectively evaluate acute (≤90 days after last dose of radiotherapy) and long-term (>90 days) cutaneous, esophageal, and fibrosis toxicity and QoL in breast cancer patients treated by adjuvant IMRT after breast surgery.

On the conversion of dose to bone to dose to water in radiotherapy treatment planning systems.

Background And Purpose: Conversion factors between dose to medium (D) and dose to water (D) provided by treatment planning systems that model the patient as water with variable electron density are currently based on stopping power ratios. In the current paper it will be illustrated that this conversion method is not correct.

Materials And Methods: Monte Carlo calculations were performed in a phantom consisting of a 2 cm bone layer surrounded by water.

Abstract ID: 222 Clinical implementation of a Monte Carlo based QA platform for validation of Tomotherapy and Cyberknife treatment plans.

Introduction: This work describes the clinical implementation of a Monte Carlo based platform for treatment plan validation for Tomotherapy and Cyberknife, including a semi-automatic plan evaluation module based on dose constraints for organs-at-risk (OAR).

Methods: The Monte Carlo-based platform Moderato [1] is based on BEAMnrc/DOSXYZnrc and allows for automated re-calculation of doses planned with Tomotherapy and Cyberknife techniques. The Prescription/Validation module generates a set of dose constraints based on the anatomical region and fractionation scheme considered.

Use of an in-house Monte Carlo platform to assess the clinical impact of algorithm-related dose differences on DVH constraints.

Purpose: The aim of the present work is to evaluate a semi-automatic prescription and validation system of treatment plans for complex delivery techniques, integrated in a Monte Carlo platform, and to investigate the clinical impact of dose differences due to the calculation algorithms, by assessing the changes in DVH constraints.

Methods: A new prescription module was implemented into the Moderato system, an in-house Monte Carlo platform, with corresponding dose constraints generated depending on the anatomical region and fractionation scheme considered. The platform was tested on 83 cases treated with Cyberknife and Tomotherapy machines, to assess whether dose variations between the re-calculated dose and the Treatment Planning System might impact the dose constraints on the sensitive structures.

About the non-consistency of PTV-based prescription in lung.

Purpose: The goal of this study is to show that the PTV concept is inconsistent for prescribing lung treatments when using type B algorithms, which take into account lateral electron transport. It is well known that type A dose calculation algorithms are not capable of calculating dose in lung correctly. Dose calculations should be based on type B algorithms.

Surface imaging, laser positioning or volumetric imaging for breast cancer with nodal involvement treated by helical TomoTherapy.

A surface imaging system, Catalyst (C-Rad), was compared with laser-based positioning and daily mega voltage computed tomography (MVCT) setup for breast patients with nodal involvement treated by helical TomoTherapy. Catalyst-based positioning performed better than laser-based positioning. The respective modalities resulted in a standard deviation (SD), 68% confidence interval (CI) of positioning of left-right, craniocaudal, anterior-posterior, roll: 2.

Clinical implementation of a Monte Carlo based treatment plan QA platform for validation of Cyberknife and Tomotherapy treatments.

Purpose: The main focus of the current paper is the clinical implementation of a Monte Carlo based platform for treatment plan validation for Tomotherapy and Cyberknife, without adding additional tasks to the dosimetry department.

Methods: The Monte Carlo platform consists of C++ classes for the actual functionality and a web based GUI that allows accessing the system using a web browser. Calculations are based on BEAMnrc/DOSXYZnrc and/or GATE and are performed automatically after exporting the dicom data from the treatment planning system.

Accelerated partial breast irradiation using robotic radiotherapy: a dosimetric comparison with tomotherapy and three-dimensional conformal radiotherapy.

Background: Accelerated partial breast irradiation (APBI) is a new breast treatment modality aiming to reduce treatment time using hypo fractionation. Compared to conventional whole breast irradiation that takes 5 to 6 weeks, APBI is reported to induce worse cosmetic outcomes both when using three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). These late normal tissue effects may be attributed to the dose volume effect because a large portion of the non-target breast tissue volume (NTBTV) receives a high dose.

Characterization of recombination effects in a liquid ionization chamber used for the dosimetry of a radiosurgical accelerator.

Most modern radiation therapy devices allow the use of very small fields, either through beamlets in Intensity-Modulated Radiation Therapy (IMRT) or via stereotactic radiotherapy where positioning accuracy allows delivering very high doses per fraction in a small volume of the patient. Dosimetric measurements on medical accelerators are conventionally realized using air-filled ionization chambers. However, in small beams these are subject to nonnegligible perturbation effects.

Treatment and technical intervention time analysis of a robotic stereotactic radiotherapy system.

The purpose of this study is to obtain a better operational knowledge of Stereotactic Body Radiotherapy (SBRT) treatments with CyberKnife(r). An analysis of both In-room Times (IRT) and technical interventions of 5 years of treatments was performed, during which more than 1600 patients were treated for various indications, including liver (21%), lung (29%), intracranial (13%), head and neck (11%) and prostate (7%). Technical interventions were recorded along with the time of the failure, time to the intervention, and the complexity and duration of the repair.