scholarly journals A novel range telescope concept for proton CT

Author(s):  
Marc Granado-González ◽  
César Jesús-Valls ◽  
Thorsten Lux ◽  
Tony Price ◽  
Federico Sánchez

Abstract Proton beam therapy can potentially offer improved treatment for cancers of the head and neck and in paediatric patients. There has been asharp uptake of proton beam therapy in recent years as improved delivery techniques and patient benefits are observed. However, treatments are currently planned using conventional x-ray CT images due to the absence of devices able to perform high quality proton computed tomography(pCT) under realistic clinical conditions. A new plastic-scintillator-based range telescope concept, named ASTRA, is proposed here to measure the proton’s energy loss in a pCT system. Simulations conducted using GEANT4 yield an expected energy resolution of 0.7%. If calorimetric information is used the energy resolution could be further improved to about 0.5%. In addition, the ability of ASTRA to track multiple protons simultaneously is presented. Due to its fast components, ASTRA is expected to reach unprecedented data collection rates, similar to 10^8 protons/s.The performance of ASTRA has also been tested by simulating the imaging of phantoms. The results show excellent image contrast and relative stopping power reconstruction.

2021 ◽  
Author(s):  
Khalid Labib Alsamadony ◽  
Ertugrul Umut Yildirim ◽  
Guenther Glatz ◽  
Umair bin Waheed ◽  
Sherif M. Hanafy

Abstract Computed tomography (CT) is an important tool to characterize rock samples allowing quantification of physical properties in 3D and 4D. The accuracy of a property delineated from CT data is strongly correlated with the CT image quality. In general, high-quality, lower noise CT Images mandate greater exposure times. With increasing exposure time, however, more wear is put on the X-Ray tube and longer cooldown periods are required, inevitably limiting the temporal resolution of the particular phenomena under investigation. In this work, we propose a deep convolutional neural network (DCNN) based approach to improve the quality of images collected during reduced exposure time scans. First, we convolve long exposure time images from medical CT scanner with a blur kernel to mimic the degradation caused because of reduced exposure time scanning. Subsequently, utilizing the high- and low-quality scan stacks, we train a DCNN. The trained network enables us to restore any low-quality scan for which high-quality reference is not available. Furthermore, we investigate several factors affecting the DCNN performance such as the number of training images, transfer learning strategies, and loss functions. The results indicate that the number of training images is an important factor since the predictive capability of the DCNN improves as the number of training images increases. We illustrate, however, that the requirement for a large training dataset can be reduced by exploiting transfer learning. In addition, training the DCNN on mean squared error (MSE) as a loss function outperforms both mean absolute error (MAE) and Peak signal-to-noise ratio (PSNR) loss functions with respect to image quality metrics. The presented approach enables the prediction of high-quality images from low exposure CT images. Consequently, this allows for continued scanning without the need for X-Ray tube to cool down, thereby maximizing the temporal resolution. This is of particular value for any core flood experiment seeking to capture the underlying dynamics.


2020 ◽  
Vol 165 ◽  
pp. 109295
Author(s):  
Kenta Takada ◽  
Hiroaki Kumada ◽  
Akira Matsumura ◽  
Hideyuki Sakurai ◽  
Takeji Sakae

2019 ◽  
Vol 20 (8) ◽  
pp. 1894 ◽  
Author(s):  
Changhoon Choi ◽  
Chansu Lee ◽  
Sung-Won Shin ◽  
Shin-Yeong Kim ◽  
Sung Noh Hong ◽  
...  

When radiotherapy is applied to the abdomen or pelvis, normal tissue toxicity in the gastrointestinal (GI) tract is considered a major dose-limiting factor. Proton beam therapy has a specific advantage in terms of reduced doses to normal tissues. This study investigated the fundamental differences between proton- and X-ray-induced intestinal injuries in mouse models. C57BL/6J mice were irradiated with 6-MV X-rays or 230-MeV protons and were sacrificed after 84 h. The number of surviving crypts per circumference of the jejunum was identified using Hematoxylin and Eosin staining. Diverse intestinal stem cell (ISC) populations and apoptotic cells were analyzed using immunohistochemistry (IHC) and a terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) assay, respectively. The crypt microcolony assay revealed a radiation-dose-dependent decrease in the number of regenerative crypts in the mouse jejunum; proton irradiation was more effective than X-ray irradiation with a relative biological effectiveness of 1.14. The jejunum is the most sensitive to radiations, followed by the ileum and the colon. Both types of radiation therapy decreased the number of radiosensitive, active cycling ISC populations. However, a higher number of radioresistant, reserve ISC populations and Paneth cells were eradicated by proton irradiation than X-ray irradiation, as shown in the IHC analyses. The TUNEL assay revealed that proton irradiation was more effective in enhancing apoptotic cell death than X-ray irradiation. This study conducted a detailed analysis on the effects of proton irradiation versus X-ray irradiation on intestinal crypt regeneration in mouse models. Our findings revealed that proton irradiation has a direct effect on ISC populations, which may result in an increase in the risk of GI toxicity during proton beam therapy.


2015 ◽  
Vol 54 (9) ◽  
pp. 1638-1642 ◽  
Author(s):  
David C. Hansen ◽  
Joao Seco ◽  
Thomas Sangild Sørensen ◽  
Jørgen Breede Baltzer Petersen ◽  
Joachim E. Wildberger ◽  
...  

2007 ◽  
Author(s):  
E. Hashimoto ◽  
A. Maksimenko ◽  
H. Sugiyama ◽  
K. Hirano ◽  
K. Hyodo ◽  
...  

2009 ◽  
Vol 19 (03n04) ◽  
pp. 143-155 ◽  
Author(s):  
KI-HONG KIM ◽  
HONG-TAE KIM ◽  
JONG-HEE KIM ◽  
SEUNG-JUN SEO ◽  
DUCK-SOO CHUNG ◽  
...  

In order to investigate the potential cytotoxic effects of particle-induced x-ray emission (PIXE) on tumor cells, 45 MeV proton beam was irradiated on C6 glioma cell lines that had taken up alginate-coated ferrite nanoparticles (Alg-SNP). Cells were anchored in vertical 96-well dishes facing a horizontal beam where the Bragg peak was placed on the upper part of the 96-well dish. Experimental groups included cells without SNP as a control (No-SNP), and cells incubated with SNP for 6 hours (6hr-SNP) or overnight (ON-SNP). A 0 to 200 Gy proton beam from an MC50 cyclotron (Scanditronix, Sweden) at the Korea Cancer Center Hospital (Seoul, Korea) was used to irradiate each experimental group. Perinuclear Alg-SNP nanoparticle distribution was observed in glioma cells. The test groups (6hr-SNP or ON-SNP) showed an estimated 20-28% (ANOVA, P < 0.05) less cell survival compared to the control group based on MTT assay. Nuclear damage, indicating apoptosis, was present at a higher frequency in the 6hr-SNP and ON-SNP groups up to relatively low radiation dose of 100 Gy by fluorescence microscopy upon Hoechst 33342 and Acridine Orange staining. Ferrite nanoparticles alone were not cytotoxic at the experimental concentration of 0.15 mg/ml. Therefore ferrite nanoparticles may induce additional cytotoxicity from X-ray emission from potential PIXE effects. PIXE and metal nanoparticles may be developed as a therapeutic factor and prodrug for localized proton beam therapy without side effects of solid or disseminate tumors on the surrounding normal tissue.


2022 ◽  
Vol 17 (01) ◽  
pp. C01010
Author(s):  
S. Kaser ◽  
T. Bergauer ◽  
A. Burker ◽  
I. Frötscher ◽  
A. Hirtl ◽  
...  

Abstract Proton computed tomography aims at improving proton-beam therapy, which is an established method to treat deep-seated tumours in cancer therapy. In treatment planning, the stopping power (SP) within a patient, describing the energy loss of a proton in a tissue, has to be known with high accuracy. However, conventional computed tomography (CT) returns Hounsfield units (HU), which have to be converted to SP values to perform the required treatment planning, thus introducing range uncertainties in the calculated dose distribution. Using protons not only for therapy but also for the preceding planning CT enables the direct measurement of the SP. Hence, this imaging modality eliminates the need for further conversion and therefore offers the possibility to improve treatment planning in proton therapy. In order to examine the principles of such a proton CT (pCT) setup, a demonstrator system, consisting of four double-sided silicon strip detectors and a range telescope, was built. The performance of the pCT demonstrator was tested with measurements at the MedAustron facility in Wiener Neustadt, Austria. In this paper, 2D imaging modalities going beyond the idea of a standard proton radiography, will be discussed. Namely, fluence loss imaging and scattering radiography results obtained with the demonstrator will be shown. The advantage of these modalities is that they do not rely on an additional energy measurement and can therefore be conducted only with the tracker of the demonstrator.


Sign in / Sign up

Export Citation Format

Share Document