Enhanced head and neck radiotherapy target definition through multidisciplinary delineation and peer review: A prospective single-center study.

This study evaluates the benefit of weekly delineation and peer review by a multidisciplinary team (MDT) of radiation oncologists (ROs), radiologists (RXs), and nuclear medicine (NM) physicians in defining primary and lymph node tumor volumes (GTVp and GTVn) for head and neck cancer (HNC) radiotherapy. This study includes 30 consecutive HNC patients referred for definitive curative (chemo)-radiotherapy. Imaging data including head and neck MRI, [18F]-FDG-PET and CT scan were evaluated by the MDT.

Pancreatic SABR using peritumoral fiducials, triggered imaging and breath-hold.

We aim to present our linear accelerator-based workflow for pancreatic stereotactic ablative radiotherapy (SABR) in order to address the following issues: intrafractional organ motion management, Cone Beam CT (CBCT) image quality, residual errors with dosimetric consequences, treatment time, and clinical results. Between 2016 and 2021, 14 patients with locally advanced pancreatic cancer were treated with induction chemotherapy and SABR using volumetric modulated arc therapy (VMAT). Internal target volume (ITV) concept (5), phase-gated (4), or breath hold (5) techniques were used.

Impact of consensus guidelines on delineation of primary tumor clinical target volume (CTVp) for head and neck cancer: Results of a national review project.

Background And Purpose: A significant interobserver variability (IOV) for clinical target volume of the primary tumor (CTVp) delineation was shown in a previous national review project. Since then, international expert consensus guidelines (CG) for the delineation of CTVp were published. The aim of this follow-up study was to 1) objectify the extent of implementation of the CG, 2) assess its impact on delineation quality and consistency, 3) identify any remaining ambiguities.

Results of a multicenter 4D computed tomography quality assurance audit: Evaluating image accuracy and consistency.

Background And Purpose: 4D Computed Tomography (4DCT) technology captures the location and movement of tumors and nearby organs at risk over time. In this study, a multi-institutional multi-vendor 4DCT audit was initiated to assess the accuracy of current imaging protocols.

Materials And Methods: Twelve centers, including thirteen scanners performed a 4DCT acquisition of a dynamic thorax phantom using the institution's own protocol with the in-house breathing monitoring system.

A comprehensive quality assurance program for four-dimensional computed tomography in radiotherapy.

This study aimed to develop and validate a comprehensive, reproducible and automatic 4DCT Quality Assurance (QA) workflow (QAMotion) that evaluates image accuracy across various regular and irregular breathing patterns. Volume and amplitude deviations, CT number accuracy, and spatial integrity were used as evaluation metrics. For repeatability tests, tolerances were respected with a mean CT number deviation < 10 HU, volume deviation < 2% and diameter and amplitude deviation < 2 mm except for irregular amplitude curves for which an amplitude deviation up to 6 mm was measured.

Patient-reported outcomes in terms of swallowing and quality of life after prophylactic versus reactive percutaneous endoscopic gastrostomy tube placement in advanced oropharyngeal cancer patients treated with definitive chemo-radiotherapy: Swall PEG study.

Background: Percutaneous endoscopic gastrostomy (PEG) is often used to provide nutritional support in locally advanced head and neck cancer patients undergoing multimodality treatment. However, there is little published data on the impact of prophylactic versus reactive PEG. PEG placement may affect swallowing-related physiology, function, and quality of life.

Pre-trial quality assurance of diffusion-weighted MRI for radiomic analysis and the role of harmonisation.

Purpose: The aim of this study was to perform a quantitative quality assurance of diffusion-weighted MRI to assess the variability of the mean apparent diffusion coefficient (ADC) and other radiomic features across the scanners involved in the REGINA trial.

Materials And Methods: The NIST/QIBA diffusion phantom was acquired on six 3 T scanners from five centres with a rectum-specific diffusion protocol. All sequences were repeated in each scan session without moving the phantom from the table.

Radiomics software comparison using digital phantom and patient data: IBSI-compliance does not guarantee concordance of feature values.

Introduction: Radiomics is a promising imaging-based tool which could enhance clinical observation and identify representative features. To avoid different interpretations, the Image Biomarker Standardisation Initiative (IBSI) imposed conditions for harmonisation. This study evaluates IBSI-compliant radiomics applications against a known benchmark and clinical datasets for agreements.

Additional Value of 18F-FDOPA Amino Acid Analog Radiotracer to Irradiation Planning Process of Patients With Glioblastoma Multiforme.

Purpose: To investigate the added value of 6-(18F]-fluoro-L-3,4-dihydroxyphenylalanine (FDOPA) PET to radiotherapy planning in glioblastoma multiforme (GBM).

Methods: From September 2017 to December 2020, 17 patients with GBM received external beam radiotherapy up to 60 Gy with concurrent and adjuvant temozolamide. Target volume delineations followed the European guideline with a 2-cm safety margin clinical target volume (CTV) around the contrast-enhanced lesion+resection cavity on MRI gross tumor volume (GTV).

Interobserver variability in organ at risk delineation in head and neck cancer.

Background: In radiotherapy inaccuracy in organ at risk (OAR) delineation can impact treatment plan optimisation and treatment plan evaluation. Brouwer et al. showed significant interobserver variability (IOV) in OAR delineation in head and neck cancer (HNC) and published international consensus guidelines (ICG) for OAR delineation in 2015.

Prophylactic gastrostomy in locally advanced head and neck cancer: results of a national survey among radiation oncologists.

Background: Nutritional complications in patients with locally advanced head and neck cancer (LA-HNC) treated by concurrent chemoradiotherapy (CCRT) often lead to placement of a prophylactic gastrostomy (PG) tube, while indication lacks harmonization. Our aim was to explore the current PG tube utilization among Belgian radiation oncology centers.

Methods: A survey was distributed to all 24 Belgian Radiation oncology departments, with questions about the number of patient treated per year, whether the PG indication is discussed at the multidisciplinary board, placement technique, time of starting nutrition and removal, its impact on swallowing function and importance of clinical factors.

Improving generalization in MR-to-CT synthesis in radiotherapy by using an augmented cycle generative adversarial network with unpaired data.

Purpose: MR-to-CT synthesis is one of the first steps in the establishment of an MRI-only workflow in radiotherapy. Current MR-to-CT synthesis methods in deep learning use unpaired MR and CT training images with a cycle generative adversarial network (CycleGAN) to minimize the effect of misalignment between paired images. However, this approach critically assumes that the underlying interdomain mapping is approximately deterministic and one-to-one.

Monte Carlo as quality control tool of stereotactic body radiation therapy treatment plans.

Purpose/objective: The objective of this study was to verify the accuracy of treatment plans of stereotactic body radiation therapy (SBRT) and to verify the feasibility of the use of Monte Carlo (MC) as quality control (QC) on a daily basis.

Material/methods: Using EGSnrc, a MC model of Agility™ linear accelerator was created. Various measurements (Percentage depth dose (PDD), Profiles and Output factors) were done for different fields sizes from 1x1 up to 40x40 (cm).

[Linac-based stereotactic ablative radiotherapy for pancreatic cancer with intrafractional triggered imaging].

Our aim was to present different treatment strategies (non-gated [NG], respiratory-gated [RG] and deep inspiration breath-hold [DIBH] technique) of linac-based stereotaxic ablative radiotherapy (SABR) for pancreatic cancer in terms of use of marker, abdominal compression, image quality, and time efficiency. From October 2016 to October 2020 14 patients were treated with VMAT-based SABR (NG: 6/14, 8/14 RG RT including 3/8 DIBH SABR). Treatment verification consisted of 3D/4D CBCTs.

HDR brachytherapy boost using MR-only workflow for intermediate- and high-risk prostate cancer: 8-year results of a pilot study.

Purpose: To report 8-year clinical outcome with high-dose-rate brachytherapy (HDRBT) boost using MRI-only workflow for intermediate (IR) and high-risk (HR) prostate cancer (PC) patients.

Methods And Materials: Fifty-two patients were treated with 46-60 Gy of 3D conformal radiotherapy preceded and/or followed by a single dose of 8-10 Gy MRI-guided HDRBT. Interventions were performed in a 0.

Combined quality and dose-volume histograms for assessing the predictive value of Tc-MAA SPECT/CT simulation for personalizing radioembolization treatment in liver metastatic colorectal cancer.

Background: The relationship between the mean absorbed dose delivered to the tumour and the outcome in liver metastases from colorectal cancer patients treated with radioembolization has already been presented in several studies. The optimization of the personalized therapeutic activity to be administered is still an open challenge. In this context, how well the Tc-MAA SPECT/CT predicts the absorbed dose delivered by radioembolization is essential.

Triggered Imaging With Auto Beam Hold and Pre-/Posttreatment CBCT During Prostate SABR: Analysis of Time Efficiency, Target Coverage, and Normal Volume Changes.

Purpose: Our purpose was to investigate time efficiency and target coverage for prostate stereotactic ablative radiation therapy (SABR) using triggered imaging (TI) and auto beam hold.

Methods And Materials: A total of 20 patients were treated with volumetric modulated arc-based SABR. Treatment verification consisted of pre- and post-radiation therapy cone beam computed tomography (CBCT) with gold marker-based TI every 3 seconds.

Stereotactic robotic body radiotherapy for patients with oligorecurrent pulmonary metastases.

Background: Our aim is to report treatment efficacy and toxicity of patients treated by robotic (Cyberknife®) stereotactic body radiotherapy (SBRT) for oligorecurrent lung metastases (ORLM). Additionally we wanted to evaluate influence of tumor, patient and treatment related parameters on local control (LC), lung and distant progression free- (lung PFS/Di-PFS) and overall survival (OS).

Methods: Consecutive patients with up to 5 ORLM (confirmed by FDG PET/CT) were included in this study.

[Multimodal imaging during lung and abdominal stereotactic ablative radiotherapy: from cine MRI through 3D/4D CBCT to intrafractional kV verification].

Our aim was to present our treatment and verification protocols of linear accelerator-based lung and abdominal stereotactic ablative radiotherapy (SABR). During our treatments both the volumetric imaging (3D/4D CBCT/CT) and triggered kV intrafractional tumor motion control could be combined allowing a full control on the whole workflow. The most optimal kV directions from which the tumor is well detectable were defined.

Interobserver variability in delineation of target volumes in head and neck cancer.

Background And Purpose: In the last decade precision of radiotherapy treatment execution increased, demanding more accurate delineations to fully exploit these developments. The aim of this study was to identify the extent of interobserver variability in delineation of head and neck cancer (HNC).

Materials And Methods: In February 2017 all Belgian radiotherapy departments were invited to complete an online survey and submit clinical target volumes for five HNC reference cases.

Prediction of GTV median dose differences eases Monte Carlo re-prescription in lung SBRT.

Background And Purpose: The use of Monte Carlo (MC) dose calculation algorithm for lung patients treated with stereotactic body radiotherapy (SBRT) can be challenging. Prescription in low density media and time-consuming optimization conducted CyberKnife centers to propose an equivalent path length (EPL)-to-MC re-prescription method based on GTV median dose. Unknown at the time of planning, GTV D50% practical application remains difficult.

A simple clinical method for predicting the benefit of prone vs. supine positioning in reducing heart exposure during left breast radiotherapy.

Background And Purpose: The benefit of reduced radiation heart exposure in the prone vs. supine position individually differs. In this prospective cohort study, the goal was to develop a simple method for the operation of a validated model for the prediction of preferable treatment position during left breast radiotherapy.