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Background: The aim of this study was to describe the clinical implementation of the Calypso system with its potential impact on the treatment delivery. Materials and methods: The influence of the electromagnetic array was investigated on the kilovoltage cone beam computed tomography (kV-CBCT) image quality using the CATPHAN 504 CBCT images. Then, the QFix kVue Calypso couch top and the array attenuation, and their dosimetric influence on the Volumetric modulated arc therapy (VMAT) treatments of prostate was evaluated. Results: Regarding the image quality, a significant increase of noise (p < 0.01) was detected with the array in place, resulting in a significant decrease in signal noise ratio (SNR) (p < 0.01). No difference in absolute contrast was observed. Finally, there was a significant decrease in contrast noise ratio (CNR) (p < 0.01) even if the deviation was only of 2.5%. For the dosimetric evaluation, the maximum attenuation of the couch was 12.02% and 13.19% for X6 and X6 flattening filter free (FFF), respectively (configuration of rails out). Besides, the mean attenuation of the array was 1.15% and 1.67% for X6 and X6 FFF, respectively. For the VMAT treatment plans, the mean dose was reduced by 0.61% for X6 and by 0.31% for X6 FFF beams when using the electromagnetic array. Conclusions: The Calypso system does not affect significantly the kV-CBCT image quality and the VMAT plan dose distribution. [ABSTRACT FROM AUTHOR]

This publication is a resume of the GOCO Congress (Montpellier 2017). A part of this congress was about the use of MRI in clinical practice, focused on the oncology field. The role of this tool was described in diagnosis, staging of tumors, evaluation of treatment response and the future use in prognostic and investigation (radiomics). After that, in the context of the present and future uses of MRI in radiation oncology, MRI guided radiotherapy was explained, as a method that allows an increased precision in image guided treatments. This publication is a resume of the GOCO Congress (Montpellier 2017). A part of this congress was about the use of MRI in clinical practice, focused on the oncology field. The role of this tool was described in diagnosis, staging of tumors, evaluation of treatment response and the future use in prognostic and investigation (radiomics). [ABSTRACT FROM AUTHOR]

Abstract Background The management of breath-induced tumor motion is a major challenge for lung stereotactic body radiation therapy (SBRT). Three techniques are currently available for these treatments: tracking (T), gating (G) and free-breathing (FB). Aim To evaluate the dosimetric differences between these three treatment techniques for lung SBRT. Materials and methods Pretreatment 4DCT data were acquired for 10 patients and sorted into 10 phases of a breathing cycle, such as 0% and 50% phases defined respectively as the inhalation and exhalation maximum. GTV ph , PTV ph (=GTV ph + 3 mm) and the ipsilateral lung were contoured on each phase. For the tracking technique, 9 fixed fields were adjusted to each PTV ph for the 10 phases. The gating technique was studied with 3 exhalation phases (40%, 50% and 60%). For the free-breathing technique, ITV FB was created from a sum of all GTV ph and a 3 mm margin was added to define a PTV FB. Fields were adjusted to PTV FB and dose distributions were calculated on the average intensity projection (AIP) CT. Then, the beam arrangement with the same monitor units was planned on each CT phase. The 3 modalities were evaluated using DVHs of each GTV ph , the homogeneity index and the volume of the ipsilateral lung receiving 20 Gy (V 20Gy). Results The FB system improved the target coverage by increasing D mean (75.87 (T) –76.08 (G) –77.49 (FB) Gy). Target coverage was slightly more homogeneous, too (HI: 0.17 (T and G) –0.15 (FB)). But the lung was better protected with the tracking system (V 20Gy : 3.82 (T) –4.96 (G) –6.34 (FB) %). Conclusions Every technique provides plans with a good target coverage and lung protection. While irradiation with free-breathing increases doses to GTV, irradiation with the tracking technique spares better the lung but can dramatically increase the treatment complexity. [ABSTRACT FROM AUTHOR]

Stereotactic body radiotherapy (SBRT) has developed over the last few years for the treatment of primary and metastatic hepatic tumors. The tumoral and adjacent peritumoral modifications caused by this radiosurgery limit the evaluation of response by anatomic imaging and dimensional criteria alone, such as with RECIST. This suggests that it is of interest to also take into account the residual enhancement and hyper metabolism of these hepatic targets. We have reviewed the English language literature regarding the response of hepatic lesions treated by SBRT, and found that only seven articles were specifically concerned with this problem. The response of the hepatocellular carcinoma after SBRT has been studied specifically with multiphase enhanced CT-scan. Criteria set by the European Association of Study of the Liver better estimate response at each time point of follow up than RECIST does. Non-enhancement, reflecting tumor necrosis, is additionally an early indicator of response with extended response in time and a best non-enhancement percentage is observed at 12 months. The response after treatment by SBRT of cholangiocarcinoma has not yet generated a specific report. Use of RECIST criteria is also inadequate in the evaluation of response after SBRT for hepatic metastases. Response of liver metastases to SBRT is better assessed with a combination of size and enhancement pattern. The occurrence of a lobulated enhancement during follow up is efficient to predict local progression in a specific, reproducible, and sensitive way. Patients with FDG-avid hepatic metastases are also better evaluated with PET-CT and functional criteria than routine imaging and metric evaluation alone. [ABSTRACT FROM AUTHOR]

Aim To evaluate the different techniques used for liver metastases Stereotactic Body Radiation Therapy (SBRT) planning. We especially focused on immobilization devices, motion management and imaging used for contouring. Background Although some guidelines exist, there is no consensus regarding the minimal requirements for liver SBRT treatments. Materials and methods We reviewed the main liver metastases SBRT publications and guidelines; and compared the techniques used for immobilization, motion management, margins and imaging. Results There is a wide variety of techniques used for immobilization, motion management and planning imaging. Conclusions We provide a subjective critical analysis of minimal requirements and ideal technique for liver SBRT planning. [ABSTRACT FROM AUTHOR]

Background Motion management is a major challenge in abdominal SBRT. We present our study of SBRT for liver tumors using intrafraction motion review (IMR) allowing simultaneous KV information and MV delivery to synchronize the beam during gated RapidArc treatment. Materials and methods Between May 2012 and March 2015, 41 patients were treated by liver SBRT using gated RapidArc technique in a Varian Novalis Truebeam STx linear accelerator. PTV was created by expanding 5 mm from the ITV. Dose prescription ranged from 40 to 50 Gy in 5–10 fractions. The prescribed dose and fractionation were chosen depending on hepatic function and dosimetric results. Thirty-four patients with a minimal follow-up of six months were analyzed for local control and toxicity. Accuracy for tumor repositioning was evaluated for the first ten patients. Results With a median follow-up of 13 months, the treatment was well tolerated and no patient presented RILD, perforation or gastrointestinal bleeding. Acute toxicity was found in 3 patients with G1 abdominal pain, 2 with G1 nausea, 10 with G1 asthenia and 1 with G2 asthenia. 6 patients presented asymptomatic transitory perturbation of liver enzymes. In-field local control was 90.3% with 7 complete responses, 14 partial responses and 7 stabilisations. 3 patients evolved “in field”. 12 patients had an intrahepatic progression “out of field”. Mean intrafraction deviation of fiducials in the craneo-caudal direction was 0.91 mm (0–6 mm). Conclusion The clinical tolerance and oncological outcomes were favorable when using image-guided liver SBRT with real-time adaptive tumor gating. [ABSTRACT FROM AUTHOR]

Aim To evaluate the tumor repositioning during gated volumetric modulated arc therapy (VMAT) for liver stereotactic body radiotherapy(SBRT) treatment using implanted fiducial markers and intrafraction kilovoltage (kV) images acquired during dose delivery. Materials and methods Since 2012, 47 liver cancer patients with implanted fiducial markers were treated using the gated VMAT technique with a Varian Truebeam STx linear accelerator. The fiducial markers were implanted inside or close to the tumor target before treatment simulation. They were defined at the maximum inhalation and exhalation phases on a 4-dimensionnal computed tomography (4DCT) acquisition. During the treatment, kV images were acquired just before the beam-on at each breathing cycle at maximum exhalation and inhalation phases to verify the fiducial markers positions. For the five first fractions of treatment in the first ten consecutive patients, a total of 2705 intrafraction kV images were retrospectively analyzed to assess the differences between expected and actual positions of the fiducial markers along the cranio-caudal (CC) direction during the exhalation phase. Results The mean absolute intrafractional fiducial marker deviation along the CC direction was 1.0 mm at the maximum exhalation phase. In 99%, 95% and 90% cases, the fiducial marker deviations were ≤4.5 mm, 2.8 mm and 2.2 mm, respectively. Conclusion Intrafraction kV images allowed us to ensure the consistency of tumor repositioning during treatment. In 99% cases, the fiducial marker deviations were ≤4.5 mm corresponding to our 5 mm treatment margin. This margin seems to be well-adapted to the gated VMAT SBRT treatment in liver disease. [ABSTRACT FROM AUTHOR]

Abstract: The SFjRO was created ten years ago to promote radiation oncology teaching in France. Our society has now more than 120 members from all around the country. Each year, two national courses are organized where all members are invited. [Copyright &y& Elsevier]