A deep learning model for inter-fraction head and neck anatomical changes in proton therapy.

To assess the performance of a probabilistic deep learning based algorithm for predicting inter-fraction anatomical changes in head and neck patients.A probabilistic daily anatomy model (DAM) for head and neck patients DAM (DAM) is built on the variational autoencoder architecture. The model approximates the generative joint conditional probability distribution of the repeat computed tomography (rCT) images and their corresponding masks on the planning CT images (pCT) and their masks.

Neurovascular bundle sparing in hypofractionated radiotherapy maintained with realistic treatment uncertainties.

Background And Purpose: Erectile dysfunction is a common side effect of radiotherapy for prostate cancer. To mitigate this toxicity, it has been suggested to limit the dose to critical nerves and vessels. We investigated the feasibility of sparing the neuro-vascular bundles (NVBs) in stereotactic body radiotherapy under the impact of realistic treatment uncertainties.

Treatment-related toxicity, utility and patient-reported outcomes of head and neck cancer patients treated with proton therapy: A longitudinal study.

Objective: In comparison to current standard photon irradiation, proton therapy (PT) significantly reduces dose to the surrounding normal tissue and therefore is expected to reduce toxicity and improve health related quality of life (HRQoL). Despite the high expectations of PT, there is very limited data on patients' HRQoL after radiotherapy. This study evaluated HRQoL in head and neck cancer (HNC) patients receiving PT and established a robust benchmark for future comparison of PT and the radiotherapy advancements.

First-in-Men Online Adaptive Robotic Stereotactic Body Radiation Therapy: Toward Ultrahypofractionation for High-Risk Prostate Cancer Patients.

Purpose: Ultrahypofractionation presents challenges for a subset of high-risk prostate cancer patients due to the large planning target volume (PTV) margin required for the seminal vesicles. Online adaptive radiation therapy could potentially reduce this margin. This paper focuses on the development, preclinical validation, and clinical testing of online adaptive robotic stereotactic body radiation therapy for this patient group.

Characterisation of the HollandPTC R&D proton beamline for physics and radiobiology studies.

HollandPTC is an independent outpatient center for proton therapy, scientific research, and education. Patients with different types of cancer are treated with Intensity Modulated Proton Therapy (IMPT). Additionally, the HollandPTC R&D consortium conducts scientific research into the added value and improvements of proton therapy.

Results of a Single-Arm Phase 2 Clinical Trial: Online Adaptive Stereotactic Body Radiation Therapy for Abdominal-Pelvic Oligometastases.

Purpose: This study reports on the clinical outcomes of the single-arm phase-2 STEAL trial investigating online adaptive stereotactic body radiation therapy (SBRT) for abdominal-pelvic lymph node (A-P LN) oligometastases.

Methods And Materials: Patients with oligometastatic A-P LN were enrolled and treated to a total dose of 45 Gy in 5 fractions on the CyberKnife. For each patient, a library of 3 plans was created using a pretreatment diagnostic computed tomography (CT) scan and the treatment planning CT scan.

Margin and robustness settings for a library-of-plans IMPT strategy for locally advanced cervical cancer.

This study aims to determine a margin and robustness setting for treating locally advanced cervical cancer (LACC) with a library-of-plans (LoP) based online-adaptive intensity-modulated proton therapy (IMPT).We analyzed 13 LACC patients with delineated planning and weekly repeat CT scans (reCTs). For each patient, 120 IMPT treatments of 25 fractions were simulated with a LoPs approach.

Evaluating and reporting LET and RBE-weighted dose in proton therapy for glioma - The Dutch approach.

Background And Purpose: With proton therapy, the relative biological effectiveness (RBE) accounts for increased DNA damage caused by higher linear energy transfer (LET) compared to photons. However, the LET and hence the RBE varies along the proton range, particularly at the Bragg peak, introducing challenges in proton treatment planning for brain tumors. The aim of this paper is to standardize evaluating and reporting LET and RBE in proton therapy for patients with grade 2 and 3 IDH mutant gliomas among the Dutch proton therapy centers.

Development of patient-specific pre-treatment verification procedure for FLASH proton therapy based on time resolved film dosimetry.

Background: Pre-clinical studies demonstrate that delivering a high dose at a high dose rate result in less toxicity while maintaining tumor control, known as the FLASH effect. In proton therapy, clinical trials have started using 250 MeV transmission beams and more trials are foreseen. A novel aspect of FLASH treatments, compared to conventional radiotherapy, is the importance of dose rate next to dose and geometry.

Stereotactic body radiation therapy on abdominal-pelvic lymph node oligometastases: a systematic review on toxicity.

Background And Purpose: To review available data on toxicity during and/or after treatment of abdominal-pelvic lymph node oligometastases (A-P LN) with stereotactic body radiation therapy (SBRT) and to provide an overview of adverse events and its relation to dose or fractionation.

Material And Methods: For this systematic review, we searched MEDLINE, Embase, Web of Science Core Collection, and CINAH for studies published between the database inception and October 3rd, 2023. Inclusion criteria were (1) patients with 1-5 A-P LN oligometastases, (2) treatment with SBRT to a median prescribed dose of ≥55 Gy BED10, and (3) description of acute and/or late toxicity.

Dosimetric advantages of adaptive IMPT vs. Enhanced workload and treatment time - A need for automation.

Introduction: In head-and-neck IMPT, trigger-based offline plan adaptation (Offline) is often used. Our goal was to compare this to four alternative adaptive strategies for dosimetry, workload and treatment time, considering also foreseen further technological advancements, including anticipated automation.

Materials And Methods: Alternative strategies included weekly offline re-planning (Offline), daily plan selection from a library (Library and Library) and a fast, approximate daily online re-optimization approach (Online).

Assessment of integrated electromagnetic tracking for dwell position monitoring in a clinical HDR brachytherapy setting for prostate cancer.

Background: Electromagnetic Tracking (EMT) technology has been integrated in a prototype high-dose-rate brachytherapy (HDR-BT) afterloading device. Its potential for dwell position (DP) monitoring has earlier been demonstrated in prostate phantoms. However, its performance for prostate BT in the clinical setting remains to be assessed.

A probabilistic evaluation of the Dutch robustness and model-based selection protocols for Head-and-Neck IMPT: A multi-institutional study.

Background And Purpose: In the Netherlands, 2 protocols have been standardized for PT among the 3 proton centers: a robustness evaluation (RE) to ensure adequate CTV dose and a model-based selection (MBS) approach for IMPT patient-selection. This multi-institutional study investigates (i) inter-patient and inter-center variation of target dose from the RE protocol and (ii) the robustness of the MBS protocol against treatment errors for a cohort of head-and-neck cancer (HNC) patients treated in the 3 Dutch proton centers.

Materials And Methods: Clinical treatment plans of 100 HNC patients were evaluated.

Two-dimensional oxygen-diffusion modelling for FLASH proton therapy with pencil beam scanning-Impact of diffusive tissue properties, dose, dose rate and scan patterns.

Oxygen depletion is generally believed to play an important role in the FLASH effect-a differential reduction of the radiosensitivity of healthy tissues, relative to that of the tumour under ultra-high dose-rate (UHDR) irradiation conditions. In proton therapy (PT) with pencil-beam scanning (PBS), the deposition of dose, and, hence, the degree of (radiolytic) oxygen depletion varies both spatially and temporally. Therefore, the resulting oxygen concentration and the healthy-tissue sparing effect through radiation-induced hypoxia varies both spatially and temporally as well.

The impact of baseline health factors on second primary cancer risk after radiotherapy for prostate cancer.

Purpose: In evaluating second primary cancers (SPCs) following External Beam Radiotherapy (EBRT), the role of lifestyle factors is frequently not considered due to data limitations. We investigated the association between smoking, comorbidities, and SPC risks within EBRT-treated patients for localized prostate cancer (PCa).

Patients & Methods: The study included 1,883 PCa survivors aged 50-79, treated between 2006 and 2013, with intensity-modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3D-CRT).

Robustness evaluation of pencil beam scanning proton therapy treatment planning: A systematic review.

Compared to conventional radiotherapy using X-rays, proton therapy, in principle, allows better conformity of the dose distribution to target volumes, at the cost of greater sensitivity to physical, anatomical, and positioning uncertainties. Robust planning, both in terms of plan optimization and evaluation, has gained high visibility in publications on the subject and is part of clinical practice in many centers. However, there is currently no consensus on the methods and parameters to be used for robust optimization or robustness evaluation.

Relating pre-treatment non-Gaussian intravoxel incoherent motion diffusion-weighted imaging to human papillomavirus status and response in oropharyngeal carcinoma.

Background And Purpose: Diffusion-weighted imaging (DWI) is a promising technique for response assessment in head-and-neck cancer. Recently, we optimized Non-Gaussian Intravoxel Incoherent Motion Imaging (NG-IVIM), an extension of the conventional apparent diffusion coefficient () model, for the head and neck. In the current study, we describe the first application in a group of patients with human papillomavirus (HPV)-positive and HPV-negative oropharyngeal squamous cell carcinoma.

Clinical practicality and patient performance for surface-guided automated VMAT gating for DIBH breast cancer radiotherapy.

Background And Purpose: To evaluate the performance of automated surface-guided gating for left-sided breast cancer with DIBH and VMAT.

Materials And Methods: Patients treated in the first year after introduction of DIBH with VMAT were retrospectively considered for analysis. With automated surface-guided gating the beam automatically switches on/off, if the surface region of interest moved in/out the gating tolerance (±3 mm, ±3°).

Dosimetric impact of bone marrow sparing for robustly optimized IMPT for locally advanced cervical cancer.

Background And Purpose: To investigate the trade-off between bone marrow sparing (BMS) and dose to organs at risk (OARs) for intensity modulated proton therapy (IMPT) for women with locally advanced cervical cancer (LACC).

Materials And Methods: Twenty LACC patients were retrospectively included. IMPT plans were created for each patient using automated treatment planning.

radiation sensitivity assessment for individual head and neck cancer patients using deep learning-based automated nuclei and DNA damage foci detection.

Introduction: Tumor biopsy tissue response to irradiation is potentially an interesting biomarker for tumor response, therefore, for treatment personalization. Tumor response can be characterized by DNA damage response, expressed by the large-scale presence of DNA damage foci in tumor nuclei. Currently, characterizing tumor nuclei and DNA damage foci is a manual process that takes hours per patient and is subjective to inter-observer variability, which is not feasible in for clinical decision making.

A fast and robust constraint-based online re-optimization approach for automated online adaptive intensity modulated proton therapy in head and neck cancer.

. In head-and-neck cancer intensity modulated proton therapy, adaptive radiotherapy is currently restricted to offline re-planning, mitigating the effect of slow changes in patient anatomies. Daily online adaptations can potentially improve dosimetry.

A review of the clinical introduction of 4D particle therapy research concepts.

Background And Purpose: Many 4D particle therapy research concepts have been recently translated into clinics, however, remaining substantial differences depend on the indication and institute-related aspects. This work aims to summarise current state-of-the-art 4D particle therapy technology and outline a roadmap for future research and developments.

Material And Methods: This review focused on the clinical implementation of 4D approaches for imaging, treatment planning, delivery and evaluation based on the 2021 and 2022 as well as a review of the most recent surveys, guidelines and scientific papers dedicated to this topic.

Evaluating AI-generated CBCT-based synthetic CT images for target delineation in palliative treatments of pelvic bone metastasis at conventional C-arm linacs.

Purpose: One-table treatments with treatment imaging, preparation and delivery occurring at one treatment couch, could increase patients' comfort and throughput for palliative treatments. On regular C-arm linacs, however, cone-beam CT (CBCT) imaging quality is currently insufficient. Therefore, our goal was to assess the suitability of AI-generated CBCT based synthetic CT (sCT) images for target delineation and treatment planning for palliative radiotherapy.