Simultaneous Integrated Boost Volumetric Modulated Arc Therapy for Middle or Lower Esophageal Cancer Using Elective Nodal Irradiation: Comparison with 3D Conformal Radiotherapy

We investigated the feasibility of simultaneous integrated boost (SIB) volumetric modulated arc therapy (VMAT) using elective nodal irradiation (ENI) for middle or lower esophageal cancer and compared it with three-dimensional conformal radiotherapy (3D-CRT). The study included 15 patients. The prescribed doses included a standard dose (50.4 Gy) and a high dose (60 Gy) for the planning target volume (PTV) of the involved lesions. The objective of the whole lung volume receiving ≥ 20 Gy (V20Gy) was 20% reduction in the mean against 3D-CRTs. Our results demonstrate the feasibility of SIB-VMAT for the treatment of middle or lower esophageal cancer with ENI. Although attention should be paid to the low-dose area of the lungs, SIB-VMAT would be a promising treatment option with improved outcomes for esophageal cancer

Ethnic comparison in takotsubo syndrome : novel insights from the International Takotsubo Registry

© The Author(s) 2021. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.Background: Ethnic disparities have been reported in cardiovascular disease. However, ethnic disparities in takotsubo syndrome (TTS) remain elusive. This study assessed differences in clinical characteristics between Japanese and European TTS patients and determined the impact of ethnicity on in-hospital outcomes. Methods: TTS patients in Japan were enrolled from 10 hospitals and TTS patients in Europe were enrolled from 32 hospitals participating in the International Takotsubo Registry. Clinical characteristics and in-hospital outcomes were compared between Japanese and European patients. Results: A total of 503 Japanese and 1670 European patients were included. Japanese patients were older (72.6 ± 11.4 years vs. 68.0 ± 12.0 years; p < 0.001) and more likely to be male (18.5 vs. 8.4%; p < 0.001) than European TTS patients. Physical triggering factors were more common (45.5 vs. 32.0%; p < 0.001), and emotional triggers less common (17.5 vs. 31.5%; p < 0.001), in Japanese patients than in European patients. Japanese patients were more likely to experience cardiogenic shock during the acute phase (15.5 vs. 9.0%; p < 0.001) and had a higher in-hospital mortality (8.2 vs. 3.2%; p < 0.001). However, ethnicity itself did not appear to have an impact on in-hospital mortality. Machine learning approach revealed that the presence of physical stressors was the most important prognostic factor in both Japanese and European TTS patients. Conclusion: Differences in clinical characteristics and in-hospital outcomes between Japanese and European TTS patients exist. Ethnicity does not impact the outcome in TTS patients. The worse in-hospital outcome in Japanese patients, is mainly driven by the higher prevalence of physical triggers.Open Access funding provided by Universität Zürich. CT has been supported by the H.H. Sheikh Khalifa bin Hamad Al-Thani Research Programme and the Swiss Heart Foundation. L.S.M. has been supported by EU HORIZON 2020 (SILICOFCM ID777204). J.R.G has received a grant “Filling the gap” from the University of Zurich. The InterTAK Registry is supported by The Biss Davies Charitable Trust.info:eu-repo/semantics/publishedVersio

Ethnic comparison in takotsubo syndrome: novel insights from the International Takotsubo Registry

Background Ethnic disparities have been reported in cardiovascular disease. However, ethnic disparities in takotsubo syndrome (TTS) remain elusive. This study assessed differences in clinical characteristics between Japanese and European TTS patients and determined the impact of ethnicity on in-hospital outcomes.Methods TTS patients in Japan were enrolled from 10 hospitals and TTS patients in Europe were enrolled from 32 hospitals participating in the International Takotsubo Registry. Clinical characteristics and in-hospital outcomes were compared between Japanese and European patients.Results A total of 503 Japanese and 1670 European patients were included. Japanese patients were older (72.6 +/- 11.4 years vs. 68.0 +/- 12.0 years; p Conclusion Differences in clinical characteristics and in-hospital outcomes between Japanese and European TTS patients exist. Ethnicity does not impact the outcome in TTS patients. The worse in-hospital outcome in Japanese patients, is mainly driven by the higher prevalence of physical triggers.</p

SU-E-T-26: A Study On the Influence of Photonuclear Reactions On the Biological Effectiveness of Therapeutic High Energy X-Ray Beam

Purpose:Photons from a modern high-energy therapeutic linear accelerator used in X-ray radiotherapy causes photonuclear reactions in an accelerator or patient\u27s body. The aim of this study is to evaluate the biological effectiveness including these particles by Microdosimetric Kinetic Model (MKM) based on microdosimetry.Methods:A linear accelerator operating at 15 MV was used. CR-39 was used to obtain LET spectra of secondary ions selectively, as CR-39 is regarded insensitive to photons. CR-39 was put on the central axis of the X-ray beam at depths of 0, 5 and 10 cm in plastic phantom at a source to detector distance of 100 cm. Pits formed by the traversal of ions were etched then analyzed to obtain restricted LET distribution. Frequency-mean and dose-mean lineal energy was evaluated from the relationship between the restricted LET and the lineal energy required to evaluate the biological effectiveness by MKM. The relationship was calculated by Monte Carlo simulations with GEANT4.Results:Restricted LET distributions of secondary particles showed broad distributions that decreases exponentially with increasing LET. Frequency-mean and dose-mean lineal energy were determined uniquely within the scope of the energies of secondary particles generated from photons of 15 MeV. The frequency-mean lineal energies at the depth of 0, 5 and 10 cm were 15.1, 16.0 and 19.7 keV/μm respectively, and the dose-mean lineal energies were 18.6, 20.5 and 19.6 keV/μm, respectively. RBE of secondary particles for HSG cell evaluated by MKM was about 2.0 at all depths, and RBE of all particles including photons was evaluated 1.0.Conclusion:We investigated the biological effectiveness of secondary particles by photonuclear reactions. The method to evaluate RBE by MKM was established with measurements and simulations. However, the influence of these secondary ions on RBE was found negligible in the entire biological effectiveness of the high-energy X-ray

Characteristics of a laser-produced proton beam improved by a synchronous RF field

We have succeeded to compress the energy spread of a laser-produced proton beam to 1.6% at FWHM by an RF electric field synchronous to the pulse laser. Protons generated by this laser originally had a continuous energy spectrum with no peaks. Radial focusing and defocusing effects caused by the transverse component of the RF field were also observed. Concerning these effects, we simulated the energy spectra from the calculated value of the electric field by POISSON; the simulation could almost reproduce the experimental results. By applying this beam as an inject ion beam of a synchrotron,a compact acceleration system for particle cancer therapy is expected to be realized

Independent assessment of source position for gynecological applicator in high-dose-rate brachytherapy

Purpose : The aim of this study is to describe a phantom designed for independent examination of a source position in brachytherapy that is suitable for inclusion in an external auditing program. Material and methods : We developed a phantom that has a special design and a simple mechanism, capable of firmly fixing a radiochromic film and tandem-ovoid applicators to assess discrepancies in source positions between the measurements and treatment planning system (TPS). Three tests were conducted: 1) reproducibility of the source positions (n = 5); 2) source movements inside the applicator tube; 3) changing source position by changing curvature of the transfer tubes. In addition, as a trial study, the phantom was mailed to 12 institutions, and 23 trial data sets were examined. The source displacement ΔX and ΔY (reference = TPS) were expressed according to the coordinates, in which the positive direction on the X-axis corresponds to the external side of the applicator perpendicular to source transfer direction Y-axis. Results : Test 1: The 1σ fell within 1 mm irrespective of the dwell positions. Test 2: ΔX were greater around the tip of the applicator owing to the source cable. Test 3: All of the source position changes fell within 1 mm. For postal audit, the mean and 1.96σ in ΔX were 0.8 and 0.8 mm, respectively. Almost all data were located within a positive region along the X-axis due to the source cable. The mean and 1.96σ in ΔY were 0.3 and 1.6 mm, respectively. The variance in ΔY was greater than that in ΔX, and large uncertainties exist in the determination of the first dwell position. The 95% confidence limit was 2.1 mm. Conclusions : In HDR brachytherapy, an effectiveness of independent source position assessment could be demonstrated. The 95% confidence limit was 2.1 mm for a tandem-ovoids applicator