A student trained convolutional neural network competing with a commercial AI software and experts in organ at risk segmentation.

This retrospective, multi-centered study aimed to improve high-quality radiation treatment (RT) planning workflows by training and testing a Convolutional Neural Network (CNN) to perform auto segmentations of organs at risk (OAR) for prostate cancer (PCa) patients, specifically the bladder and rectum. The objective of this project was to develop a clinically applicable and robust artificial intelligence (AI) system to assist radiation oncologists in OAR segmentation. The CNN was trained using manual contours in CT-datasets from diagnostic Ga-PSMA-PET/CTs by a student, then validated (n = 30, PET/CTs) and tested (n = 16, planning CTs).

Outcome of intraoperative brachytherapy as a salvage treatment for locally recurrent rectal cancer.

Background: Locally advanced recurrent rectal cancer (RRC) requires a multimodal approach. Intraoperative high-dose-rate brachytherapy (HDR-BT) may reduce the risk of local recurrence. However, the optimal therapeutic regimen remains unclear.

Evaluating the impact of a rigid and a deformable registration method of pre-treatment images for hypoxia-based dose painting.

Purpose: To assess the impact of rigid and deformable image registration methods (RIR, DIR) on the outcome of a hypoxia-based dose painting strategy.

Materials And Methods: Thirty head and neck cancer patients were imaged with [F]FMISO-PET/CT before radiotherapy. [F]FMISO-PET/CT images were registered to the planning-CT by RIR or DIR.

Predictors of radiation-induced late rectal toxicity in prostate cancer treatment: a volumetric and dosimetric analysis.

Introduction: Prostate cancer (PCa) is a prevalent malignancy in European men, often treated with radiotherapy (RT) for localized disease. While modern RT achieves high success rates, concerns about late gastrointestinal (GI) toxicities persist. This retrospective study aims to identify predictors for late GI toxicities following definitive conventionally fractionated external beam RT (EBRT) for PCa, specifically exploring the dose to the rectal wall.

The significance of partial volume effect on the estimation of hypoxic tumour volume with [F]FMISO PET/CT.

Background: The purpose of this study was to evaluate how a retrospective correction of the partial volume effect (PVE) in [F]fluoromisonidazole (FMISO) PET imaging, affects the hypoxia discoverability within a gross tumour volume (GTV). This method is based on recovery coefficients (RC) and is tailored for low-contrast tracers such as FMISO. The first stage was the generation of the scanner's RC curves, using spheres with diameters from 10 to 37 mm, and the same homogeneous activity concentration, positioned in lower activity concentration background.

The role of the soft palate dose regarding normal tissue toxicities in older adults with head and neck cancer undergoing definitive radiotherapy.

Purpose: The number of older adults with head and neck squamous cell carcinoma (HNSCC) is continuously increasing. Older HNSCC patients may be more vulnerable to radiotherapy-related toxicities, so that extrapolation of available normal tissue complication probability (NTCP) models to this population may not be appropriate. Hence, we aimed to investigate the correlation between organ at risk (OAR) doses and chronic toxicities in older patients with HNSCC undergoing definitive radiotherapy.

Development and evaluation of two open-source nnU-Net models for automatic segmentation of lung tumors on PET and CT images with and without respiratory motion compensation.

Objectives: In lung cancer, one of the main limitations for the optimal integration of the biological and anatomical information derived from Positron Emission Tomography (PET) and Computed Tomography (CT) is the time and expertise required for the evaluation of the different respiratory phases. In this study, we present two open-source models able to automatically segment lung tumors on PET and CT, with and without motion compensation.

Materials And Methods: This study involved time-bin gated (4D) and non-gated (3D) PET/CT images from two prospective lung cancer cohorts (Trials 108237 and 108472) and one retrospective.

Evaluation of RADIANCE Monte Carlo algorithm for treatment planning in electron based Intraoperative Radiotherapy (IOERT).

Purpose: To perform experimental as well as independent Monte Carlo (MC) evaluation of the MC algorithm implemented in RADIANCE version 4.0.8, a dedicated treatment planning system (TPS) for 3D electron dose calculations in intraoperative radiation therapy (IOERT).

Free automatic software for quality assurance of computed tomography calibration, edges and radiomics metrics reproducibility.

Purpose: To develop a QA procedure, easy to use, reproducible and based on open-source code, to automatically evaluate the stability of different metrics extracted from CT images: Hounsfield Unit (HU) calibration, edge characterization metrics (contrast and drop range) and radiomic features.

Methods: The QA protocol was based on electron density phantom imaging. Home-made open-source Python code was developed for the automatic computation of the metrics and their reproducibility analysis.

Recurrence analysis of glioblastoma cases based on distance and dose information.

Background And Purpose: Radiation therapy for glioblastoma (GBM) typically involves large target volumes. The aim of this study was to examine the recurrence pattern of GBM following modern radiochemotherapy according to EORTC guidelines and provide dose and distance information for the choice of optimal target volume margins.

Materials And Methods: In this study, the recurrences of 97 GBM patients, treated with radiochemotherapy from 2013 to 2017 at the Medical Center- University of Freiburg, Germany were analysed.

Comparison of protocols with respiratory-gated (4D) motion compensation in PET/CT: open-source package for quantification of phantom image quality.

Background: Patient's breathing affects the quality of chest images acquired with positron emission tomography/computed tomography (PET/CT) studies. Movement correction is required to optimize PET quantification in clinical settings. We present a reproducible methodology to compare the impact of different movement compensation protocols on PET image quality.

The use of deep learning in interventional radiotherapy (brachytherapy): A review with a focus on open source and open data.

Deep learning advanced to one of the most important technologies in almost all medical fields. Especially in areas, related to medical imaging it plays a big role. However, in interventional radiotherapy (brachytherapy) deep learning is still in an early phase.

Deep inspiration breath-hold radiation therapy in left-sided breast cancer patients: a single-institution retrospective dosimetric analysis of organs at risk doses.

Background: Radiotherapy can induce cardiac injury in left-sided breast cancer cases. Cardiac-sparing irradiation using the deep inspiration breath-hold (DIBH) technique can achieve substantial dose reduction to vulnerable cardiac substructures compared with free breathing (FB). This study evaluated the dosimetric differences between both techniques at a single institution.

Determination of the dose rate around a HDR Ir brachytherapy source with the microDiamond and the microSilicon detector.

Purpose: To employ the microDiamond and the microSilicon detector (mDD and mSD, both PTW-Freiburg, Germany) to determine the dose rate around a HDR Ir brachytherapy source (model mHDR-v2r, Elekta AB, Sweden).

Methods: The detectors were calibrated with a Co beam at the PTW Calibration Laboratory. Measurements around the Ir source were performed inside a PTW MP3 water phantom.

Cost effectiveness and health-related quality of life of chemoradiotherapy versus radiation therapy alone in elderly head and neck cancer patients.

Purpose: Radiotherapy (RT) constitutes a mainstay in the treatment of elderly patients with head and neck cancer (HNC), but use of simultaneous chemoradiotherapy (CRT) remains controversial. We have conducted a prospective analysis based on real-world patient data to examine the health-related quality of life (HRQoL) and cost effectiveness (CE) of CRT vs. RT in elderly HNC patients.

Incidental irradiation of the regional lymph nodes during deep inspiration breath-hold radiation therapy in left-sided breast cancer patients: a dosimetric analysis.

Background: Radiotherapy using the deep inspiration breath-hold (DIBH) technique compared with free breathing (FB) can achieve substantial reduction of heart and lung doses in left-sided breast cancer cases. The anatomical organ movement in deep inspiration also cause unintended exposure of locoregional lymph nodes to the irradiation field.

Methods: From 2017-2020, 148 patients with left-sided breast cancer underwent breast conserving surgery (BCS) or mastectomy (ME) with axillary lymph node staging, followed by adjuvant irradiation in DIBH technique.

PSMA-PET- and MRI-Based Focal Dose Escalated Radiation Therapy of Primary Prostate Cancer: Planned Safety Analysis of a Nonrandomized 2-Armed Phase 2 Trial (ARO2020-01).

Purpose: The bicentric HypoFocal phase 2 trial investigates the implementation of molecular imaging with positron-emission tomography targeting prostate-specific membrane antigen (PSMA-PET) into modern focal dose-escalation radiation therapy (RT) concepts in 2 nonrandomized arms. We present the planned safety analysis after 6 months of follow-up.

Materials And Methods: Intermediate- and high-risk localized primary prostate cancer patients staged with multiparametric magnet resonance tomography and PSMA-PET were either treated with focal dose-escalated moderately hypofractionated RT (arm A) or single fraction high-dose-rate brachytherapy followed by external beam RT (arm B).

Optimization of hippocampus sparing during whole brain radiation therapy with simultaneous integrated boost-tutorial and efficacy of complete directional hippocampal blocking.

Purpose: Hippocampus-avoidance whole brain radiotherapy with simultaneous integrated boost (HA-WBRT+SIB) is a complex treatment option for patients with multiple brain metastases, aiming to prevent neurocognitive decline and simultaneously increase tumor control. Achieving efficient hippocampal dose reduction in this context can be challenging. The aim of the current study is to present and analyze the efficacy of complete directional hippocampal blocking in reducing the hippocampal dose during HA-WBRT+SIB.

Feasibility, pitfalls and results of a structured concept-development phase for a randomized controlled phase III trial on radiotherapy in primary prostate cancer patients.

Objective: Failure rate in randomized controlled trials (RCTs) is > 50%, includes safety-problems, underpowered statistics, lack of efficacy, lack of funding or insufficient patient recruitment and is even more pronounced in oncology trials. We present results of a structured concept-development phase (CDP) for a phase III RCT on personalized radiotherapy (RT) in primary prostate cancer (PCa) patients implementing prostate specific membrane antigen targeting positron emission tomography (PSMA-PET).

Materials And Methods: The 1 yr process of the CDP contained five main working packages: (i) literature search and scoping review, (ii) involvement of individual patients, patients' representatives and patients' self-help groups addressing the patients' willingness to participate in the preparation process and the conduct of RCTs as well as the patient informed consent (PIC), (iii) involvement of national and international experts and expert panels (iv) a phase II pilot study investigating the safety of implementation of PSMA-PET for focal dose escalation RT and (v) in-silico RT planning studies assessing feasibility of envisaged dose regimens and effects of urethral sparing in focal dose escalation.

The value of plasma hypoxia markers for predicting imaging-based hypoxia in patients with head-and-neck cancers undergoing definitive chemoradiation.

Background: Tumor hypoxia worsens the prognosis of head-and-neck squamous cell carcinoma (HNSCC) patients, and plasma hypoxia markers may be used as biomarkers for radiotherapy personalization. We therefore investigated the role of the hypoxia-associated plasma proteins osteopontin, galectin-3, vascular endothelial growth factor (VEGF) and connective tissue growth factor (CTGF) as surrogate markers for imaging-based tumor hypoxia.

Methods: Serial blood samples of HNSCC patients receiving chemoradiation within a prospective trial were analyzed for osteopontin, galectin-3, VEGF and CTGF concentrations.