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To report an interim clinical evaluation of combined external beam irradiation (EBRT) and interstitial or regional hyperthermia in the treatment of locally advanced prostate cancer. From 1997 to 2001, 26 patients with T3-4/NX/0M0 prostate carcinoma were treated with a combination of conformal EBRT and hyperthermia. Fourteen patients received five weekly regional hyperthermia treatments within an optimization (phase II) study, using the coaxial transverse electrical magnetic system. Twelve patients received one interstitial hyperthermia treatment within a feasibility study (phase I), using the multi-electrode current source system. Irradiation was delivered using a conformal three-field technique, administering 70 Gy in 2-Gy fractions in 7 weeks. The mean initial prostate-specific antigen level was 26 ng/mL. Three patients had a T4 and 23 a T3 tumour; the tumours were classified as well (four), moderately (16) and poorly (six) differentiated. The mean follow-up was 36 months. In the combined treatments there was no toxicity of more than grade 2. In regional hyperthermia the mean index temperature (T90 and T50, i.e. exceeded by 90% and 50% of the measurements) was 40.2 °C and 40.8 °C, and for interstitial hyperthermia 39.4 °C and 41.8 °C, respectively. All patients survived; seven patients had a biochemical relapse (27%), three in the regional and four in the interstitial group. The actuarial probability of freedom from biochemical relapse was 70% at 36 months for all patients together, 79% for regional and 57% for interstitial. No factors were found that could be used to predict relapse. The clinical outcome in these patients with advanced localized prostate cancer seems to compare favourably with most series using irradiation alone, and the treatment caused no severe complications. [ABSTRACT FROM AUTHOR]

• Deep-learning networks for prediction of PBS and VMAT doses were established. • Relative errors between planned and predicted doses were minimal in the target. • Strong correlation (r > 0.9) was found between planned and predicted DVH metrics. • The networks classified the PBS dosimetric benefit over VMAT with 98% precision. • Proposed networks can accurately predict the treatment modality selection outcome. Dose prediction using deep learning networks prior to radiotherapy might lead tomore efficient modality selections. The study goal was to predict proton and photon dose distributions based on the patient-specific anatomy and to assess their clinical usage for paediatric abdominal tumours. Data from 80 patients with neuroblastoma or Wilms' tumour was included. Pencil beam scanning (PBS) (5 mm/ 3%) and volumetric-modulated arc therapy (VMAT) plans (5 mm) were robustly optimized on the internal target volume (ITV). Separate 3-dimensional patch-based U-net networks were trained to predict PBS and VMAT dose distributions. Doses, planning-computed tomography images and relevant optimization masks (ITV, vertebra and organs-at-risk) of 60 patients were used for training with a 5-fold cross validation. The networks' performance was evaluated by computing the relative error between planned and predicted dose-volume histogram (DVH) parameters for 20 inference patients. In addition, the organs-at-risk mean dose difference between modalities was calculated using planned and predicted dose distributions (ΔD mean = D VMAT -D PBS). Two radiation oncologists performed a blind PBS/VMAT modality selection based on either planned or predicted ΔD mean. Average DVH differences between planned and predicted dose distributions were ≤ |6%| for both modalities. The networks classified the organs-at-risk D mean difference as a gain (ΔD mean > 0) with 98% precision. An identical modality selection based on planned compared to predicted ΔD mean was made for 18/20 patients. Deep learning networks for accurate prediction of proton and photon dose distributions for abdominal paediatric tumours were established. These networks allowing fast dose visualisation might aid in identifying the optimal radiotherapy technique when experience and/or resources are unavailable. [ABSTRACT FROM AUTHOR]

Radiation therapy (RT) is an essential component of effective cancer care and is used across nearly all cancer types. The delivery of RT is becoming more precise through rapid advances in both computing and imaging. The direct integration of magnetic resonance imaging (MRI) with linear accelerators represents an exciting development with the potential to dramatically impact cancer research and treatment. These impacts extend beyond improved imaging and dose deposition. Real-time MRI-guided RT is actively transforming the work flows and capabilities of virtually every aspect of RT. It has the opportunity to change entirely the delivery methods and response assessments of numerous malignancies. This review intends to approach the topic of MRI-based RT guidance from a vendor neutral and international perspective. It also aims to provide an introduction to this topic targeted towards oncologists without a speciality focus in RT. Speciality implications, areas for physician education and research opportunities are identified as they are associated with MRI-guided RT. The uniquely disruptive implications of MRI-guided RT are discussed and placed in context. We further aim to describe and outline important future changes to the speciality of radiation oncology that will occur with MRI-guided RT. The impacts on RT caused by MRI guidance include target identification, RT planning, quality assurance, treatment delivery, training, clinical workflow, tumour response assessment and treatment scheduling. In addition, entirely novel research areas that may be enabled by MRI guidance are identified for future investigation. • We present a review on the current state of MR-guided RT (RT). • Speciality implications, areas for physician education and research opportunities are identified. • Some impacts include target identification, quality assurance and tumour response assessment. [ABSTRACT FROM AUTHOR]

Poster discussion: PH: Adaptive radiotherapy and interfraction motion management 2 PD-0557: Biomechanical quality assurance criteria for deformable registration in image guided radiotherapy C. Zachiu, B. Denis de Senneville, M. Ries, B.W. Raaymakers. [Extracted from the article]

Poster Highlights: Poster highlights 17 CL: Palliation PH-0529: Prostate intrafraction motion during the full course of MR-guided radiotherapy sessions D. De Muinck Keizer, L.G.W. Kerkmeijer, T. Willigenburg, M.D. Den Hartogh, J.R.N. Van der Voort van Zyp, E.N. De Groot-van Breugel, B.W. Raaymakers, J.J.W. Lagendijk, H.C.J. De Boer. [Extracted from the article]