scholarly journals A New Technology for Fast Two-Dimensional Detection of Proton Therapy Beams

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Robert Hollebeek ◽  
Mitch Newcomer ◽  
Godwin Mayers ◽  
Brian Delgado ◽  
Gaurav Shukla ◽  
...  
Keyword(s):  
Dose Rate ◽  
Spatial Resolution ◽  
Proton Therapy ◽  
Time Resolution ◽  
High Energy Physics ◽  
High Energy ◽  
High Dose Rate ◽  
High Dose ◽  
High Time Resolution ◽  
High Count

The Micromesh Gaseous Structure, or Micromegas, is a technology developed for high count-rate applications in high-energy physics experiments. Tests using a Micromegas chamber and specially designed amplifiers and readout electronics adapted to the requirements of the proton therapy environment and providing both excellent time and high spatial resolution are presented here. The device was irradiated at the Roberts Proton Therapy Center at the University of Pennsylvania. The system was operated with ionization gains between 10 and 200 and in low and intermediate dose-rate beams, and the digitized signal is found to be reproducible to 0.8%. Spatial resolution is determined to be 1.1 mm (1σ) with a 1 ms time resolution. We resolve the range modulator wheel rotational frequency and the thicknesses of its segments and show that this information can be quickly measured owing to the high time resolution of the system. Systems of this type will be extremely useful in future treatment methods involving beams that change rapidly in time and spatial position. The Micromegas design resolves the high dose rate within a proton Bragg peak, and measurements agree with Geant4 simulations to within 5%.

Development of a simultaneous imaging system to measure the optical and gamma ray images of Ir-192 source for high-dose-rate brachytherapy

2021 ◽  
Vol 16 (12) ◽  
pp. T12005
Author(s):  
J. Nagata ◽  
S. Yamamoto ◽  
Y. Noguchi ◽  
T. Nakaya ◽  
K. Okudaira ◽  
...  
Keyword(s):  
Dose Rate ◽  
Spatial Resolution ◽  
Gamma Camera ◽  
Gamma Ray ◽  
Imaging System ◽  
High Dose Rate ◽  
High Dose ◽  
Cmos Camera ◽  
Absolute Position ◽  
The Absolute

Abstract In high-dose-rate (HDR) brachytherapy, verification of the Ir-192 source's position during treatment is needed because such a source is extremely radioactive. One of the methods used to measure the source position is based on imaging the gamma rays from the source, but the absolute position in a patient cannot be confirmed. To confirm the absolute position, it is necessary to acquire an optical image in addition to the gamma ray image at the same time as well as the same position. To simultaneously image the gamma ray and optical images, we developed an imaging system composed of a low-sensitivity, high-resolution gamma camera integrated with a CMOS camera. The gamma camera has a 1-mm-thick cerium-doped yttrium aluminum perovskite (YAIO3: YAP(Ce)) scintillator plate optically coupled to a position-sensitive photomultiplier (PSPMT), and a 0.1-mm-diameter pinhole collimator was mounted in front of the camera to improve spatial resolution and reduce sensitivity. We employed the concept of a periscope by placing two mirrors tilted at 45 degrees facing each other in front of the gamma camera to image the same field of view (FOV) for the gamma camera and the CMOS camera. The spatial resolution of the imaging system without the mirrors at 100 mm from the Ir-192 source was 3.2 mm FWHM, and the sensitivity was 0.283 cps/MBq. There was almost no performance degradation observed when the mirrors were positioned in front of the gamma camera. The developed system could measure the Ir-192 source positions in optical and gamma ray images. We conclude that the developed imaging system has the potential to measure the absolute position of an Ir-192 source in real-time clinical measurements.

A quantitative FLASH effectiveness model to reveal potentials and pitfalls of high dose rate proton therapy

2022 ◽  
Author(s):  
Miriam Krieger ◽  
Steven Water ◽  
Michael M Folkerts ◽  
Alejandro Mazal ◽  
Silvia Fabiano ◽  
...  
Keyword(s):  
Dose Rate ◽  
Proton Therapy ◽  
High Dose Rate ◽  
High Dose ◽  
Effectiveness Model

Imaging of Ir-192 source using a high energy gamma camera for high-dose-rate brachytherapy

2019 ◽  
Vol 126 ◽  
pp. 106128 ◽  
Author(s):  
Seiichi Yamamoto ◽  
Katsunori Yogo ◽  
Yumiko Noguchi ◽  
Takayoshi Nakaya ◽  
Kuniyasu Okudaira
Keyword(s):  
Dose Rate ◽  
Gamma Camera ◽  
High Energy ◽  
High Dose Rate ◽  
High Dose ◽  
High Dose Rate Brachytherapy ◽  
High Energy Gamma ◽  
Energy Gamma

scholarly journals Advanced scintillation materials for calorimetry at circular colliders

2021 ◽  
Vol 57 (4) ◽  
pp. 479-484
Author(s):  
M. V. Korzhik
Keyword(s):  
Time Resolution ◽  
First Generation ◽  
High Energy Physics ◽  
Hadron Collider ◽  
High Energy ◽  
High Time ◽  
Wide Energy Range ◽  
High Time Resolution ◽  
Electron Positron ◽  
Wide Energy

The most probable scenario for the development of experimental high-energy physics in the next 50 years is the creation of a family of Future Circular Colliders (FCC) at CERN, a Circular Electron–Positron Collider at China, and a Future Electron-Ion Collider at Brookhaven (USA), which continue the Large Hadron Collider (LHC) scientific program within the framework of the Standard Model and beyond it. The first generation of colliders to be put into operation will utilize the electron beam as one of the colliding species to provide precise mass spectroscopy in a wide energy range. Similarly to the measurements at the high luminosity phase of the LHC operation, the most important property of the detectors to be used in the experimental setup is a combination of the short response of the detectors and their high time resolution. The radiation tolerance to a harsh irradiation environment remains mandatory but not the main factor of the collider’s experiments using electronic beams. A short response in combination with high time resolution ensures minimization of the influence of the pile-up and spill-over effects at the high frequency of collisions (higher than 50 MGz). The radiation hardness of the materials maintains the long-term high accuracy of the detector calibration. This paper discusses the prospects for using modern inorganic scintillation materials for calorimetric detectors at future colliders.

scholarly journals Early Toxicities After High Dose Rate Proton Therapy in Cancer Treatments

2021 ◽  
Vol 10 ◽  
Author(s):  
Jérôme Doyen ◽  
Marie-Pierre Sunyach ◽  
Fabien Almairac ◽  
Véronique Bourg ◽  
Arash O. Naghavi ◽  
...  
Keyword(s):  
Dose Rate ◽  
Proton Therapy ◽  
Malignant Tumors ◽  
Retrospective Chart Review ◽  
High Dose Rate ◽  
High Dose ◽  
Cancer Treatments ◽  
Conventional Dose ◽  
Grade 3

BackgroundThe conventional dose rate of radiation therapy is 0.01–0.05 Gy per second. According to preclinical studies, an increased dose rate may offer similar anti-tumoral effect while dramatically improving normal tissue protection. This study aims at evaluating the early toxicities for patients irradiated with high dose rate pulsed proton therapy (PT).Materials and MethodsA single institution retrospective chart review was performed for patients treated with high dose rate (10 Gy per second) pulsed proton therapy, from September 2016 to April 2020. This included both benign and malignant tumors with ≥3 months follow-up, evaluated for acute (≤2 months) and subacute (>2 months) toxicity after the completion of PT.ResultsThere were 127 patients identified, with a median follow up of 14.8 months (3–42.9 months). The median age was 55 years (1.6–89). The cohort most commonly consisted of benign disease (55.1%), cranial targets (95.1%), and were treated with surgery prior to PT (56.7%). There was a median total PT dose of 56 Gy (30–74 Gy), dose per fraction of 2 Gy (1–3 Gy), and CTV size of 47.6 ml (5.6–2,106.1 ml). Maximum acute grade ≥2 toxicity were observed in 49 (38.6%) patients, of which 8 (6.3%) experienced grade 3 toxicity. No acute grade 4 or 5 toxicity was observed. Maximum subacute grade 2, 3, and 4 toxicity were discovered in 25 (19.7%), 12 (9.4%), and 1 (0.8%) patient(s), respectively.ConclusionIn this cohort, utilizing high dose rate proton therapy (10 Gy per second) did not result in a major decrease in acute and subacute toxicity. Longer follow-up and comparative studies with conventional dose rate are required to evaluate whether this approach offers a toxicity benefit.

The effect of high dose rate transient gamma radiation on high-energy optical fibers

2009 ◽  
Author(s):  
A. Akinci ◽  
M. D. Bowden ◽  
M. C. Cheeseman ◽  
S. L. Knowles ◽  
D. C. Meister ◽  
...  
Keyword(s):  
Gamma Radiation ◽  
Dose Rate ◽  
Optical Fibers ◽  
High Energy ◽  
High Dose Rate ◽  
High Dose
Sign in / Sign up

Export Citation Format

Share Document