Metal artefact reduction for accurate tumour delineation in radiotherapy.

Background And Purpose: Two techniques for metal artefact reduction for computed tomography were studied in order to identify their impact on tumour delineation in radiotherapy.

Materials And Methods: Using specially designed phantoms containing metal implants (dental, spine and hip) as well as patient images, we investigated the impact of two methods for metal artefact reduction on (A) the size and severity of metal artefacts and the accuracy of Hounsfield Unit (HU) representation, (B) the visual impact of metal artefacts on image quality and (C) delineation accuracy. A metal artefact reduction algorithm (MAR) and two types of dual energy virtual monochromatic (DECT VM) reconstructions were used separately and in combination to identify the optimal technique for each implant site.

A modeling study of functional magnetic resonance imaging to individualize target definition of seminal vesicles for external beam radiotherapy.

Background: Pre-treatment magnetic resonance imaging (MRI) can give patient-specific evaluation of suspected pathologically involved volumes in the seminal vesicles (SV) in prostate cancer patients. By targeting this suspicious volume we hypothesize that radiotherapy is more efficient without introducing more toxicity. In this study we evaluate the concept of using MRI-defined target volumes in terms of tumor control probability (TCP) and rectal normal tissue complication probability (NTCP).

Deep inspiration breath-hold radiotherapy for lung cancer: impact on image quality and registration uncertainty in cone beam CT image guidance.

Objective: We investigated the impact of deep inspiration breath-hold (DIBH) and tumour baseline shifts on image quality and registration uncertainty in image-guided DIBH radiotherapy (RT) for locally advanced lung cancer.

Methods: Patients treated with daily cone beam CT (CBCT)-guided free-breathing (FB) RT had an additional CBCT in DIBH at three fractions. These CBCT scans were offline rigidly registered (on tumour) to FB and DIBH CT scans acquired at planning.

Geometric uncertainties in voluntary deep inspiration breath hold radiotherapy for locally advanced lung cancer.

Background And Purpose: Deep inspiration breath hold (DIBH) increases lung volume and can potentially reduce treatment-related toxicity in locally advanced lung cancer. We estimated geometric uncertainties in visually guided voluntary DIBH and derived the appropriate treatment margins for different image-guidance strategies.

Material And Methods: Seventeen patients were included prospectively.

A treatment planning and delivery comparison of volumetric modulated arc therapy with or without flattening filter for gliomas, brain metastases, prostate, head/neck and early stage lung cancer.

Background: Flattening filter-free (FFF) beams are an emerging technology that has not yet been widely implemented as standard practice in radiotherapy centers. To facilitate the clinical implementation of FFF, we attempted to elucidate the difference in plan quality and treatment delivery time compared to flattening filter beams (i.e.

Reduced lung dose and improved inspiration level reproducibility in visually guided DIBH compared to audio coached EIG radiotherapy for breast cancer patients.

Introduction: Patients with left-sided breast cancer with lymph node involvement have routinely been treated with enhanced inspiration gating (EIG) for a decade at our institution. In a transition from EIG to deep inspiration breath hold (DIBH) we compared the two techniques with focus on target coverage, dose to organs at risk and reproducibility of the inspiration level (IL).

Material And Methods: Twenty-four patients were computed tomography (CT) scanned with EIG and DIBH.

Translational and rotational intra- and inter-fractional errors in patient and target position during a short course of frameless stereotactic body radiotherapy.

Background: Implementation of cone beam computed tomography (CBCT) in frameless stereotactic body radiotherapy (SBRT) of lung tumours enables setup correction based on tumour position. The aim of this study was to compare setup accuracy with daily soft tissue matching to bony anatomy matching and evaluate intra- and inter-fractional translational and rotational errors in patient and target positions.

Material And Methods: Fifteen consecutive SBRT patients were included in the study.

A closer look at RapidArc® radiosurgery plans using very small fields.

RapidArc® has become the treatment of choice for an increasing number of treatment sites in many clinics. The extensive use of multiple subfields in RapidArc® treatments presents unique challenges, especially for small targets treated in few fractions. In this work, very small static fields and subsequently RapidArc® and conventional plans for two targets (0.