scholarly journals “Warm liquid” detector for measuring dose profiles from ionizing radiation

2020 ◽  
Vol 22 (3) ◽  
pp. 228-236
Author(s):  
V. V. Siksin
Keyword(s):  
Proton Beam ◽  
Proton Therapy ◽  
Dose Distribution ◽  
Bragg Peak ◽  
Beam Width ◽  
Great Accuracy ◽  
Therapy Session ◽  
High Dose ◽  
Water Phantom ◽  
Accuracy Measure

The use of “warm liquid” tetramethylsilane (TMS) in ionization chambers for measuring dose profiles in water phantoms to prepare the accelerator for a proton therapy session is relevant. One of the promising areas of radiation therapy is proton therapy. To increase the conformality of proton therapy, it is important to know exactly the dose distributions from the energy release of the proton beam in the water phantom before conducting a proton therapy session. A television-type detector (TTD), which measures the profiles of the Bragg peak by the depth of the beam in the water phantom, helps to increase the accuracy of the dose distribution knowledge. To accurately determine the profile of the Bragg peak by the beam width in the water phantom, an additional method is proposed that will allow TTD to quickly determine the profile by the width of the Bragg peak in on-line mode. This prefix to the TTD will improve the quality of summing up the therapeutic beam-thanks to accurate knowledge of the profile by width, and therefore the formed high-dose distribution field will correspond to the irradiated volume in the patient and will increase the conformality of irradiation. The additional prefix to the TTD is designed on an organosilicon “warm liquid” and represents a high-precision ionization chamber with coordinate sensitivity along the width of the water phantom. The fully developed technology for obtaining “warm liquid” TMS allows creating both microdosimeters for proton therapy and detectors for measuring “dose profiles” in water phantoms during accelerator calibration. The considered prefix to the TTD detector - the calibrator meter of the dose field (KIDP) - can also be used independently of the TTD and with great accuracy measure the dose profiles of the Bragg peak in the water phantom, both in depth and width. KIDP can also be used to measure the outputs of secondary “instantaneous” neutrons and gamma quanta emitted from the water phantom orthogonally to the direction of the proton beam.

scholarly journals An Iterating Method to Calculate the Geometry of Range Modulation Wheel in Passive Proton Therapy

2019 ◽  
pp. 1-11
Author(s):  
Zahra Sadat Tabatabaeian ◽  
Mahdi Sadeghi ◽  
Mohammad Reza Ghasemi
Keyword(s):  
Monte Carlo Simulation ◽  
Monte Carlo ◽  
Penetration Depth ◽  
Proton Beam ◽  
Proton Therapy ◽  
Bragg Peak ◽  
Particle Energy ◽  
Absorption Energy ◽  
Energy Proton ◽  
Spread Out Bragg Peak

In the passive method of proton therapy, range modulation wheel is used to scatter the single energy proton beam. It rounds and scatters the single energy proton beam to the spectrum of particles that covers cancerous tissue by a change in penetration depth. Geant4 is a Monte Carlo simulation platform for studying particles behaviour in a matter. We simulated proton therapy nozzle with Geant4. Geometric properties of this nozzle have some effects on this beam absorption plot. Concerning the relation between penetration depth and proton particle energy, we have designed a range modulation wheel to have an approximately flat plot of absorption energy. An iterative algorithm programming helped us to calculate the weight and thickness of each sector of range modulation wheel. Flatness and practical range are calculated for resulting spread-out Bragg peak.

scholarly journals Multifunctional ionization chamber and its electronic path for use on the medical accelerator "Prometeus"

2020 ◽  
Vol 23 (3) ◽  
pp. 229-240
Author(s):  
V. V. Siksin
Keyword(s):  
Proton Therapy ◽  
Ionization Chamber ◽  
Accurate Determination ◽  
Absorbed Dose ◽  
Incident Beam ◽  
Operating Mode ◽  
Therapy Session ◽  
Proton Accelerator ◽  
High Dose ◽  
Scanning Beam

The article describes the proposed new multifunctional ionization chamber (MIC) designed to measure dose profiles when the medical accelerator "Prometheus" is operating in the scanning "pencil beam" mode. A digital image acquisition detector (DIDE) with a tissue-equivalent water phantom is used to calibrate the accelerator before a radiation therapy session. The application of the CPPI on the beam of a proton accelerator operating in the mode of beam splitting into spots with a scanning beam is considered. The CDPI detector allows for a few accelerator pulses in on-line mode to see how the energy release of each spot is distributed over the area of the irradiated target, which is the actual calibration of the accelerator before the proton therapy session. During the proton therapy session, it is planned to install the MIC directly in front of the patient. The MIC chamber contains two ionization chambers operating simultaneously — a pad chamber (PC) operating on gas or "warm liquid" and a strip ionization chamber operating only on gas (SC). At the accelerator "Prometheus" it is proposed to use a MIC, which will be used in the mode of operation by the method of active scanning with a "pencil" proton beam. The use of the MIC operation is intended to control the density of the beam intensity during the irradiation of the "target" in the patient during the proton therapy session. In case of violation of the planned operating mode of the accelerator and the beam goes beyond the parameters preset before the session, the deviation detection control system (SDMS) will turn off the accelerator. The device of the readout electronics (SE) of the MIC and SKOO cameras is described. This proposed detector, including the MIC and SKOO camera and the reading electronics serving it, will improve the quality of the therapeutic beam supply, due to the accurate determination of the absorbed dose density supplied by the scanning beam to each spot of the irradiated target, and therefore the generated high dose distribution field will correspond to the irradiated volume of the patient and will increase the safety and control of patient exposure to the target. The PC included in the MIC is designed on a "warm liquid" (or gas) and is a high-precision ionization chamber with coordinate sensitivity over the width of the irradiated target. The SC included in the MIC operates on gas and controls the direction of the incident beam to a given spot in the target. A version of the charge-sensitive preamplifier (QCD) and the SE system designed for experimental verification of the MIC prototype has been developed. The SCOO circuit working in conjunction with the MIC camera allows you to control the predetermined parameters of the irradiation of the patient's target boundaries and turns off the accelerator if these parameters deviate from the initially specified ones.

scholarly journals Multi-Institutional Phase II Study of High-Dose Hypofractionated Proton Beam Therapy in Patients With Localized, Unresectable Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma

2016 ◽  
Vol 34 (5) ◽  
pp. 460-468 ◽  
Author(s):  
Theodore S. Hong ◽  
Jennifer Y. Wo ◽  
Beow Y. Yeap ◽  
Edgar Ben-Josef ◽  
Erin I. McDonnell ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Proton Beam ◽  
Phase Ii ◽  
Proton Therapy ◽  
Intrahepatic Cholangiocarcinoma ◽  
Performance Status ◽  
Proton Beam Therapy ◽  
Phase Iii ◽  
High Dose ◽  
Ecog Performance Status

Purpose To evaluate the efficacy and safety of high-dose, hypofractionated proton beam therapy for hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC). Materials and Methods In this single-arm, phase II, multi-institutional study, 92 patients with biopsy-confirmed HCC or ICC, determined to be unresectable by multidisciplinary review, with a Child-Turcotte-Pugh score (CTP) of A or B, ECOG performance status of 0 to 2, no extrahepatic disease, and no prior radiation received 15 fractions of proton therapy to a maximum total dose of 67.5 Gy equivalent. Sample size was calculated to demonstrate > 80% local control (LC) defined by Response Evaluation Criteria in Solid Tumors (RECIST) 1.0 criteria at 2 years for HCC patients, with the parallel goal of obtaining acceptable precision for estimating outcomes for ICC. Results Eighty-three patients were evaluable: 44 with HCC, 37 with ICC, and two with mixed HCC/ICC. The CTP score was A for 79.5% of patients and B for 15.7%; 4.8% of patients had no cirrhosis. Prior treatment had been given to 31.8% of HCC patients and 61.5% of ICC patients. The median maximum dimension was 5.0 cm (range, 1.9 to 12.0 cm) for HCC patients and 6.0 cm (range, 2.2 to 10.9 cm) for ICC patients. Multiple tumors were present in 27.3% of HCC patients and in 12.8% of ICC patients. Tumor vascular thrombosis was present in 29.5% of HCC patients and in 28.2% of ICC patients. The median dose delivered to both HCC and ICC patients was 58.0 Gy. With a median follow-up among survivors of 19.5 months, the LC rate at 2 years was 94.8% for HCC and 94.1% for ICC. The overall survival rate at 2 years was 63.2% for HCC and 46.5% ICC. Conclusion High-dose hypofractionated proton therapy demonstrated high LC rates for HCC and ICC safely, supporting ongoing phase III trials of radiation in HCC and ICC.

scholarly journals A Literature Review of Proton Beam Therapy for Prostate Cancer in Japan

2019 ◽  
Vol 8 (1) ◽  
pp. 48 ◽  
Author(s):  
Rika Maglente Hoshina ◽  
Taeko Matsuura ◽  
Kikuo Umegaki ◽  
Shinichi Shimizu
Keyword(s):  
Prostate Cancer ◽  
Data Analysis ◽  
Literature Review ◽  
Proton Beam ◽  
Proton Therapy ◽  
Secondary Data ◽  
Proton Beam Therapy ◽  
Secondary Data Analysis ◽  
High Dose ◽  
Pubmed Database

Aim: Patients of proton beam therapy (PBT) for prostate cancer had been continuously growing in number due to its promising characteristics of high dose distribution in the tumor target and a sharp distal fall-off. Considering the large number of proton beam facilities in Japan, the further increase of patients undergoing this treatment is due to the emendations by Japanese National Health Insurance (NHI) and the development of medical equipment and technology, it is necessary to know what kind of research and advancements has been done on proton therapy for prostate cancer in the country. For these reasons, this literature review was conducted. The aim of this review is to identify and discuss research studies of proton beam therapy for prostate cancer in Japan. These include observational, interventional, and secondary data analysis of published articles. Method: A literature review on published works related to proton beam therapy for prostate cancer in Japan was conducted using articles that were gathered in the PubMed database of June 2018. We went through abstracts and manuscripts written in English with the keywords ‘proton beam therapy’, ‘prostate cancer’, and ‘Japan’. Results: A total of 23 articles were included. Fourteen articles were observational studies, most of which focused on the adverse effects of Proton Beam Therapy (PBT). Seven articles were interventional studies related on treatment planning, equipment parts, as well as target positioning. Two were secondary data analysis. The included studies were published in 13 different journals by different institutions using various equipment. Conclusion: Despite the favorable results of proton beam therapy, future research should include more patients and longer follow-up schedules to clarify the definitive role of PBT, yet, up to recent retrospective studies, included in this paper, concluded that PBT can be a suitable treatment option for localized prostate cancer. In addition, interventional studies were conducted by several institutions to further embellish proton therapy.

scholarly journals Pet imaging of dose distribution in proton-beam cancer therapy

2005 ◽  
Vol 20 (1) ◽  
pp. 23-26 ◽  
Author(s):  
Joanne Beebe-Wang ◽  
Avraham Dilmanian ◽  
Stephen Peggs ◽  
David Schlyer ◽  
Paul Vaska
Keyword(s):  
Positron Emission Tomography ◽  
Proton Beam ◽  
Proton Therapy ◽  
Dose Distribution ◽  
Nuclear Interaction ◽  
Target Volume ◽  
Emission Tomography ◽  
Positron Emission ◽  
Positron Emitters ◽  
Radio Isotopes

Proton therapy is a treatment modality of increasing utility in clinical radiation oncology mostly because its dose distribution conforms more tightly to the target volume than X-ray radiation therapy. One important feature of proton therapy is that it produces a small amount of positron-emitting isotopes along the beam-path through the non-elastic nuclear interaction of protons with target nuclei such as 12C, 14N, and 16O. These radio isotopes, mainly 11C, 13N, and 15O, al low imaging the therapy dose distribution using positron emission tomography. The resulting positron emission tomography images provide a powerful tool for quality assurance of the treatment, especially when treating inhomogeneous organs such as the lungs or the head-and-neck, where the calculation of the dose distribution for treatment planning is more difficult. This pa per uses Monte Carlo simulations to predict the yield of positron emitters produced by a 250 MeV proton beam, and to simulate the productions of the image in a clinical PET scanner.

scholarly journals Detectors for in vivo range and dose verification in proton therapy

2016 ◽  
Vol 44 ◽  
pp. 1660217 ◽  
Author(s):  
R. Alarcon ◽  
D. Blyth ◽  
E. Galyaev ◽  
J. Holmes ◽  
L. Ice ◽  
...  
Keyword(s):  
Proton Beam ◽  
Proton Therapy ◽  
Bragg Peak ◽  
Dose Verification ◽  
Particle Detection ◽  
Under Construction ◽  
Proton Dose ◽  
Better Than ◽  
Range Verification

Particle detection instrumentation to address the in vivo verifications of proton dose and range is under development as part of a proton therapy research program focused on patient quality assurance. For in vivo proton range verification, a collimated gamma detector array is under construction to indirectly measure the position of the Bragg peak for each proton beam spot to within 1–2 mm precision. For dose flux verification, a proton fluence detector based on the technology of the Micromegas is under construction. This detector has an active area of about 100 cm2, coordinate resolution of better than 1 mm, and handling of incident proton beam fluxes of 109–1013 particles/s.

Comparison of beam optics for normal conducting and superconducting gantry beamlines applied to proton therapy

2019 ◽  
Vol 34 (36) ◽  
pp. 1942015 ◽  
Author(s):  
Bin Qin ◽  
Runxiao Zhao ◽  
Xu Liu ◽  
Qushan Chen ◽  
Heming Chen ◽  
...  
Keyword(s):  
Proton Therapy ◽  
Dose Distribution ◽  
Bragg Peak ◽  
Distribution Characteristics ◽  
Comparison Study ◽  
Beam Optics ◽  
Design Considerations ◽  
Peak Dose ◽  
Multiple Field ◽  
Related Design

Due to the unique “Bragg peak” dose-distribution characteristics of proton beams, the proton therapy (PT) is recognized as one of the most precise and effective radiotherapy methods for tumors. A gantry is required to project the beam onto a tumor at various angles for multiple-field irradiation, and a superconducting beamline can significantly reduce the size and weight of the gantry. A PT system is under development at Huazhong University of Science and Technology (HUST), and this paper presents a comparison study of the beam optics and related design considerations for normal conducting and superconducting gantry beamlines.

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