Imaging with protons at MedAustron Ulrich-Pur, F.; Bergauer, T.; Burker, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2020, Letnik:
978
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Ion beam therapy has become a frequently applied form of cancer therapy over the last years. The advantage of ion beam therapy over conventional radiotherapy using photons is the strongly localized ...dose deposition, leading to a reduction of dose applied to surrounding healthy tissue. Currently, treatment planning for proton therapy is based on X-ray computed tomography, which entails certain sources of inaccuracy in calculation of the stopping power (SP). A more precise method to acquire the SP is to directly use high energy protons (or other ions such as carbon) and perform proton computed tomography (pCT). With this method, the ions are tracked prior to entering and after leaving the patient and finally their residual energy is measured at the very end. Therefore, an ion imaging demonstrator, comprising a tracking telescope made from double-sided silicon strip detectors and a range telescope as a residual energy detector, was set up. First measurements with this setup were performed at beam tests at MedAustron, a center for ion therapy and research in Wiener Neustadt, Austria. The facility provides three rooms for cancer treatment with proton beams as well as one which is dedicated to non-clinical research.
This contribution describes the principle of ion imaging with proton beams in general as well as the design of the experimental setup. Moreover, first results from simulations and recent beam tests as well as ideas for future developments will be presented.
LGAD technology for HADES, accelerator and medical applications Krüger, W.; Bergauer, T.; Galatyuk, T. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
09/2022, Letnik:
1039
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Low Gain Avalanche Diode (LGAD) technology has been used to design and construct prototype and full-size beam detector systems for applications requiring simultaneous time and spatial precision. For ...these purposes, a dedicated LGAD strip sensor production has been conducted at Fondazione Bruno Kessler (FBK) with different strip geometries and sizes. This contribution will review a wide variety of LGAD applications ranging from the reaction time (T0) detector for experiments utilizing proton and pion beams with the High Acceptance Di-Electron Spectrometer (HADES) at GSI in Darmstadt, Germany, to beam structure monitoring at the Superconducting DArmstadt LINear ACcelerator (S-DALINAC) at the Technische Universität Darmstadt operated in energy recovery mode and medical applications at the MedAustron facility in Wiener Neustadt, Austria. We will also give a prospect of further upgrade projects at GSI and FAIR facilities.
Energy loss of protons from MedAustron in silicon strip sensors Paulitsch, P.; Bergauer, T.; Blöch, D. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
04/2020, Letnik:
958
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MedAustron is a hadron synchrotron primarily designed and built for tumor treatment. Besides its clinical purpose, it is equipped with a dedicated beam line for non-clinical research. This beam line ...can be used for beam tests utilizing protons with an energy up to 252.7MeV at the moment, but 800MeV protons and carbon ions will become available through 2019. We conducted first beam tests at MedAustron in order to understand the usability of this beam line for testing silicon detectors. This includes the design and commissioning of a trigger setup based on scintillators and PMTs, which is meant to stay permanently there. This allowed us to measure energy deposition utilizing silicon strip sensors read out by the ALiBaVa system. Nominal beam energies were varied between 62.4 and 252.7MeV and verified by determining the specific energy loss of protons in silicon. As these energies are rather low compared to typical HEP beam tests, the proton beam through the setup was simulated to determine the necessary energy correction due to losses through matter and air in front of the Si sensor. These approaches yielded good agreement with reference data from NIST, so MedAustron is considered as a reliable facility for future beam tests.
An extensive comparison of the path uncertainty in single particle tracking systems for ion imaging was carried out based on Monte Carlo simulations. The spatial resolution as function of system ...parameters such as geometry, detector properties and the energy of proton and helium beams was investigated to serve as a guideline for hardware developments. Primary particle paths were sampled within a water volume and compared to the most likely path estimate obtained from detector measurements, yielding a depth-dependent uncertainty envelope. The maximum uncertainty along this curve was converted to a conservative estimate of the minimal radiographic pixel spacing for a single set of parameter values. Simulations with various parameter settings were analysed to obtain an overview of the reachable pixel spacing as function of system parameters. The results were used to determine intervals of detector material budget and position resolution that yield a pixel spacing small enough for clinical dose calculation. To ensure a pixel spacing below 2 mm, the material budget of a detector should remain below 0.25 % for a position resolution of 200 \(\mathrm{\mu m}\) or below 0.75 % for a resolution of 10 \(\mathrm{\mu m}\). Using protons, a sub-millimetre pixel size could not be achieved for a phantom size of 300 mm or at a large clearance. With helium ions, a sub-millimetre pixel spacing could be achieved even for a large phantom size and clearance, provided the position resolution was less than 100 \(\mathrm{\mu m}\) and material budget was below 0.75 %.
Ion beam therapy has become a frequently applied form of cancer therapy over the last years. The advantage of ion beam therapy over conventional radiotherapy using photons is the strongly localized ...dose deposition, leading to a reduction of dose applied to surrounding healthy tissue. Currently, treatment planning for proton therapy is based on X-ray computed tomography, which entails certain sources of inaccuracy in alculation of the stopping power (SP). A more precise method to acquire the SP is to directly use high energy protons (or other ions such as carbon) and perform proton computed tomography (pCT). With this method, the ions are tracked prior to entering and after leaving the patient and finally their residual energy is measured at the very end. Therefore, an ion imaging demonstrator, comprising a tracking telescope made from double-sided silicon strip detectors and a range telescope as a residual energy detector, was set up. First measurements with this setup were performed at beam tests at MedAustron, a center for ion therapy and research in \mbox{Wiener Neustadt}, \mbox{Austria}. The facility provides three rooms for cancer treatment with proton beams as well as one which is dedicated to non-clinical research. This contribution describes the principle of ion imaging with proton beams in general as well as the design of the experimental setup. Moreover, first results from simulations and recent beam tests as well as ideas for future developments will be presented.
Background: Gemcitabine is an active antitumor agent in the treatment of advanced pancreatic cancer, and has shown potential synergistic activity with the oral fluoropyrimidine capecitabine in ...previous phase I/II trials. Based on this background and in order to define the therapeutic potential and tolerance of this combination more precisely, the present randomized multicenter phase II trial was initiated. Patients and methods: We prospectively randomized 83 patients to treatment with biweekly gemcitabine 2200 mg/m2 given as a 30 min intravenous infusion on day 1, or the same treatment plus oral capecitabine 2500 mg/m2 given from days 1 to 7. In both arms, chemotherapy was administered for a duration of 6 months unless there was prior evidence of progressive disease. The efficacy of the two treatment arms was evaluated according to standard criteria, i.e. objective response, progression-free survival (PFS) and overall survival (OS), as well as by analysis of clinical benefit response. Results: The overall objective response rate among the 42 patients treated with gemcitabine alone was 14% compared with 7/41 (17%) among those treated with the combination arm. Similar to response rates, there was no apparent difference between the two groups in terms of median PFS (4.0 versus 5.1 months) and median OS (8.2 versus 9.5 months) in the gemcitabine and combination arm, respectively. Of 61 patients with tumor-related symptoms, who were considered evaluable for clinical benefit response, 10/30 (33%) and 15/31 (48.4%) experienced significant palliation in the gemcitabine and combination arm, respectively. Chemotherapy was well tolerated in both arms with only four versus six patients experiencing WHO grade 3 symptoms. Apart from the occurrence of hand–foot syndrome in 10 patients, no major increase in incidence and/or degree of adverse reactions was noted in the combination arm. Conclusions: Results of this trial suggest a fairly good therapeutic index for the combination of biweekly high-dose gemcitabine and capecitabine for the treatment of advanced pancreatic cancer. Despite a somewhat superior clinical benefit response rate, no advantage over single-agent gemcitabine, however, was noted in terms of objective efficacy parameters.
There is no established second-line treatment for advanced pancreatic cancer after gemcitabine failure. In view of the urgent need for such therapy, and since preclinical and phase I clinical data ...suggest an encouraging, potentially synergistic activity between raltitrexed and irinotecan, the present randomised phase II study was initiated. A total of 38 patients with metastatic pancreatic adenocarcinoma, who progressed while receiving or within 6 months after discontinuation of palliative first-line chemotherapy with gemcitabine, were enrolled in this study. They were randomised to 3-weekly courses of raltitrexed 3 mg x m(-2) on day 1 (arm A) or irinotecan 200 mg x m(-2) on day 1 plus raltitrexed 3 mg x m(-2) on day 2 (arm B). The primary study end point was objective response, secondary end points included progression-free survival (PFS) and overall survival (OS), as well as clinical benefit response in symptomatic patients (n=28). In the combination arm, the IRC-confirmed objective response rate was 16% (three out of 19 patients had a partial remission; 95% CI, 3-40%), which was clearly superior to that in the comparator/control arm with raltitrexed alone, in which no response was obtained. Therefore, the trial was already stopped at the first stage of accrual. Also, the secondary study end points, median PFS (2.5 vs 4.0 months), OS (4.3 vs 6.5 months), and clinical benefit response (8 vs 29%) were superior in the combination arm. The objective and subjective benefits of raltitrexed+irinotecan were not negated by severe, clinically relevant treatment-related toxicities: gastrointestinal symptoms (42 vs 68%), partial alopecia (0 vs 42%), and cholinergic syndrome (0 vs 21%) were more commonly noted in arm B; however, grade 3 adverse events occurred in only three patients in both treatment groups. Our data indicate that combined raltitrexed+irinotecan seems to be an effective salvage regimen in patients with gemcitabine-pretreated pancreatic cancer. The superior response activity, PFS and OS (when compared to raltitrexed), as well as its tolerability and ease of administration suggest that future trials with this combination are warranted.
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