[en] Radiotherapy is a curative treatment of malignant tumours. Radiotherapy techniques considerably evolved last years with the increasing integration of medical images in conformal radiotherapy. This technique makes it possible to elaborate a complex ballistics conforming to target volume and sparing healthy tissues. The examination currently used to delineate volumes of interest is Computed Tomography (CT), on account of its geometrical precision and the information that it provides on electronic densities needed to dose calculation. Magnetic Resonance Imaging (MRI) ensures a more precise delineation of target volumes in many locations, such as pelvis and brain. For pelvic tumours, the use of MRI needs image registration, which complicates treatment planning and poses the problem of the lack of in vivo standard method of validation. The obstacles in the use of MRI alone in treatment planning were evaluated. Neither geometrical distortion linked with the system and the patient nor the lack of information on electronic densities represent stumbling obstacles. Distortion remained low even in edge of large field of view on modern machines. The assignment of electronic densities to bone structures and soft tissues in MR images permitted to obtain equivalent dosimetry to that carried out on the original CT, with a good reproducibility and homogeneous distribution within target volume. The assignment of electronic densities could not be carried out using 20 MV photons and suitable ballistics. The development of Image Guided Radiotherapy could facilitate the use of MRI alone in treatment planning. Target volumes and organ at risk delineation is a time consuming task in radiotherapy planning. We took part in the development and evaluated a method of automatic and semi automatic delineation of volumes of interest from MRI images for prostate cancer radiotherapy. For prostate and organ at risk automatic delineation an organ model-based method and a seeded region growing method were used respectively. Our results are reproducible with minimal repercussion on dosimetry. (author)

[en] Late complications are one of the major factors limiting radiotherapy treatment, and their treatment is not codified. Hyperbaric oxygen (HBO) has been used in combination with radiotherapy for over half a century, either to maximise its effectiveness or in an attempt to treat late complications. In this latter case, retrospective trials and case reports are prevailing in literature. This prompted European Society for Therapeutic Radiotherapy and Oncology and European Committee for Hyperbaric Medicine to organise a consensus conference in October 2001, dealing with the HBO indications on radiotherapy for the treatment and prevention of late complications. This updated literature review is part of the documents the jury based its opinion on. A systematic search was done on literature from 1960 to 2004, by only taking into account the articles that appeared in peer review journals. Hyperbaric oxygen treatment involving complications to the head and neck, pelvis and nervous system, and the prevention of complications after surgery in irradiated tissues have been studied. Despite the small number of controlled trials, it may be indicated for the treatment of mandibular osteoradionecrosis in combination with surgery, haemorrhagic cystitis resistant to conventional treatments and the prevention of osteoradionecrosis after dental extraction, whose level of evidence seems to be the most significant though randomised trials are still necessary. The other treatment methods are also outlined for each location

[en] A retrospective study of the use of palliative external beam radiotherapy (EBRT) in nine patients with Erdheim-Chester disease was conducted through the Rare Cancer Network. Patients received EBRT for bone pain, brain infiltration, or retro-orbital involvement. EBRT typically provided short-term palliation, with later recurrence of symptoms in most cases

[en] We have developed a 0D model of aqueous organic redox flow battery to have a better understanding of the impact of oxygen and hydrogen evolution as a parasitic side reaction on the evolution of the battery performances. This lumped approach model is able to account for multiple redox processes at each electrode, which, to our knowledge has not been described in the literature. In this article the study is focused on alkaline battery and the model has been validated on 2,6-dihydroanthraquinone/ferrocyanide electrolytes at laboratory full cell level. The model considers the electrochemical reactions, the electrolyte flow rate, the diffusion of the electroactive molecules from the bulk to the reaction sites, the transfer of cations through a perfluorosulfonic membrane and the ohmic losses. Furthermore, the electrochemical reactions accounted for include the reduction and the oxidation of water modeled with Tafel slopes. Thanks to this approach, we highlight the non-negligible role of oxygen evolution reaction in these conditions. The model is used as a tool to optimize operating conditions as well as to predict the most advantageous potential of electrolytes to enhance performances and limit side reactions. For example, under alkaline condition (pH = 14), the negolyte standard potential can be targeted to -0.8 V without competing with HER, however, the posolyte potential must be kept below 0.65 V to avoid competition with OER.

[en] Purpose: Given that postprostatectomy recurrence of prostate cancer occurs in 10-40% of patients, the best use of immediate postoperative radiotherapy (RT) in high-risk patients and salvage RT for biochemical recurrence remains a topic of debate. We assessed the levels of evidence (in terms of efficacy, prognostic factors, and toxicity) for the following treatment strategies: immediate postoperative RT alone, salvage RT alone, and the addition of androgen deprivation therapy to the two RT strategies. Methods and Materials: A systematic literature search for controlled randomized trials, noncontrolled trials, and retrospective studies between 1990 and 2008 was performed on PubMed, CancerLit, and MEDLINE. Only relevant articles that had appeared in peer-reviewed journals were selected. We report on the levels of evidence (according to the National Cancer Institute guidelines) supporting the various treatment strategies. Results: Immediate postoperative RT improves biochemical and clinical progression-free survival (Level of evidence, 1.ii) but has no significant effect on metastasis-free survival or overall survival. A pathologic review is of particular importance for correctly analyzing the treatment strategies. Low-grade morbidity has been significantly greater in the postoperative groups, but no severe toxicity has been observed. The influence of immediate postoperative RT on postprostatectomy continence appears to be slight; therefore, immediate postoperative RT should be considered in patients with major risk factors for local relapse (Level of evidence, 1.ii). On the basis of extensive retrospective data, salvage RT is effective in biochemical relapse after prostatectomy; some patients with few adverse prognostic factors might also benefit from salvage RT (Level of evidence, 3.ii). The addition of androgen deprivation therapy to immediate postoperative or salvage RT has only been supported by weak, retrospective data (Level of evidence, 3.ii). Conclusion: Prospective randomized trials are needed to compare immediate postoperative RT with salvage RT and to assess the value of androgen deprivation therapy in this setting

[en] The establishment of an MRI-only workflow in radiotherapy depends on the ability to generate an accurate synthetic CT (sCT) for dose calculation. Previously proposed methods have used a Generative Adversarial Network (GAN) for fast sCT generation in order to simplify the clinical workflow and reduces uncertainties. In the current paper we use a conditional Generative Adversarial Network (cGAN) framework called pix2pixHD to create a robust model prone to multicenter data.

This study included T2-weighted MR and CT images of 19 patients in treatment position from 3 different sites. The cGAN was trained on 2D transverse slices of 11 patients from 2 different sites. Once trained, the network was used to generate sCT images of 8 patients coming from a third site. The Mean Absolute Errors (MAE) for each patient were evaluated between real and synthetic CTs. A radiotherapy plan was optimized on the sCT series and re-calculated on CTs to assess the dose distribution in terms of voxel-wise dose difference and Dose Volume Histograms (DVH) analysis.

It takes on average of $7.5s$ to generate a complete sCT (88 slices) for a patient on our GPU. The average MAE in HU between the sCT and actual patient CT (within the body contour) is 48.5 ± 6 HU with our method. The maximum dose difference to the target is 1.3%.

This study demonstrates that an sCT can be generated in a multicentric context, with fewer pre-processing steps while being fast and accurate. (paper)

[en] Limited pelvic nodal relapse of prostatic cancer is a paramount challenge for locoregional salvage treatments. Salvage whole pelvis radiation therapy as considered in the BLINDED trial is an attractive option, but there are concerns about its toxicity. This article describes early toxicity with the technique.

[en] To assess the efficacy and safety of salvage stereotactic body radiation therapy (SBRT) in patients with biopsy-proven local prostate cancer recurrence after radiation therapy.

[en] Accelerated partial breast irradiation (APBI) is a new breast treatment modality aiming to reduce treatment time using hypo fractionation. Compared to conventional whole breast irradiation that takes 5 to 6 weeks, APBI is reported to induce worse cosmetic outcomes both when using three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). These late normal tissue effects may be attributed to the dose volume effect because a large portion of the non-target breast tissue volume (NTBTV) receives a high dose. In the context of APBI, non-coplanar beams could spare the NTBTV more efficiently. This study evaluates the dosimetric benefit of using the Cyberknife (CK) for APBI in comparison to IMRT (Tomotherapy) and three dimensional conformal radiotherapy (3D-CRT). The possibility of using surgical clips, implanted during surgery, to track target movements is investigated first. A phantom of a female thorax was designed in-house using the measurements of 20 patients. Surgical clips of different sizes were inserted inside the breast. A treatment plan was delivered to the mobile and immobile phantom. The motion compensation accuracy was evaluated using three radiochromic films inserted inside the breast. Three dimensional conformal radiotherapy (3D-CRT), Tomotherapy (TOMO) and CK treatment plans were calculated for 10 consecutive patients who received APBI in Lille. To ensure a fair comparison of the three techniques, margins applied to the CTV were set to 10 mm. However, a second CK plan was prepared using 3 mm margins to evaluate the benefits of motion compensation. Only the larger clips (VITALITEC Medium-Large) could be tracked inside the larger breast (all gamma indices below 1 for 1 % of the maximum dose and 1 mm). All techniques meet the guidelines defined in the NSABP/RTOG and SHARE protocols. As the applied dose volume constraints are very strong, insignificant dosimetric differences exist between techniques regarding the PTV coverage and the sparing of the lung and heart. However, the CK may be used to reduce high doses received by the NTBTV more efficiently. Robotic stereotactic radiotherapy may be used for APBI to more efficiently spare the NTBTV and improve cosmetic results of APBI

[en] Highlights: • Composition of the gut microbiome modulates cancer immune set-points. • Microbiome may trigger immune system to observe more systemic abscopal effect. • Current evidence suggests that the gut microbiome influences radiotherapy efficacy. • Gut microbiome is a key modulator in radiation-induced gastro-intestinal mucositis. Radiation therapy (RT) is an essential component of therapy either curative or palliative armamentarium in oncology, but its efficacy varies considerably among patients through many extrinsic and intrinsic mechanisms of the tumour, which are beginning to be better understood. Recent studies have shown that the gut microbiome represents a key factor in the modulation of the systemic immune response and consequently on patients’ outcome. Moreover, the emergence of biomarkers that are derived from the gut microbiota has fuelled the development of adjuvant strategies for patients treated with immunotherapy in combination or not with RT. Despite progress in development of more precise radiotherapy techniques, almost all patients undergoing RT to the abdomen, pelvis, or rectum develop acute adverse events as a consequence of several dose-limiting parameters such as the location of irradiation that may subsequently damage normal tissue including the intestinal epithelium. Several lines of evidence in preclinical models identified that vancomycin improves RT-induced gastrointestinal toxicities such as diarrhea and oral mucositis. In order to gain further insight into this rapidly evolving field, we have systematically reviewed the studies that have described how the gut microbiome may directly or indirectly modulate RT efficacy and its gastro-intestinal toxicities. Lastly, we outline current knowledge gaps and discuss potentially more satisfactory therapeutic options to restore the functionality of the gut microbiome of patients treated with RT.