Dosimetric Audit for Clinical Linac X-Rays Calibration

2021 ◽  
Vol 91 (3) ◽  
pp. 102-113
Author(s):  
M. P. Shatenok ◽  
A. N. Moiseev ◽  
K. V. Tolkachev ◽  
S. A. Ryghov ◽  
Yu. V. Drughinina ◽  
...  

The CDT guidelines on external dosimetry audit of linear accelerators x-ray beams absolute calibration is described. The guidelines specify audits organization, conduction and results analysis for 4-20 MeV photon beams, including measurement methodology, equipment and staff specification. The guidelines are designed for medical physicists, dosimetrists and management of external beam radiotherapy departments.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seongwook Choi ◽  
Eun-Yeong Park ◽  
Sinyoung Park ◽  
Jong Hyun Kim ◽  
Chulhong Kim

AbstractX-ray induced acoustic imaging (XAI) is an emerging biomedical imaging technique that can visualize X-ray absorption contrast at ultrasound resolution with less ionizing radiation exposure than conventional X-ray computed tomography. So far, medical linear accelerators or industrial portable X-ray tubes have been explored as X-ray excitation sources for XAI. Here, we demonstrate the first feasible synchrotron XAI (sXAI). The synchrotron generates X-rays, with a dominant energy of 4 to 30 keV, a pulse-width of 30 ps, a pulse-repetition period of 2 ns, and a bunch-repetition period of 940 ns. The X-ray induced acoustic (XA) signals are processed in the Fourier domain by matching the signal frequency with the bunch-repetition frequency. We successfully obtained two-dimensional XA images of various lead targets. This novel sXAI tool could complement conventional synchrotron applications.


2019 ◽  
Vol 6 (06) ◽  
pp. 4505-4510
Author(s):  
Dr. Maha Alamodi Alghamdi ◽  
Abdulaziz Saleh Altwjri ◽  
Abdullah Alsuhaibani ◽  
Abdulaziz Alsaif

Intraoperative radiotherapy during breast-conserving surgery is being studied as an alternative to 6 weeks of external beam radiotherapy (EBRT) for low-risk women; it can be delivered using electrons (intraoperative electron radiotherapy, IOERT) or 50-kV X-rays. Intraoperative radiation therapy (IORT) may pose a risk for wound complications.  Between March 2018 and June 2018, 5 breast cancer patients, all eligible for breast conserving surgery (BCS), were treated at the King Saud Medical city with IORT using the IOERT. Complete data sets for age, stage (T, N, and M), and histology and hormone receptor status were available in 5 cases. Parameters to identify eligible patients are as follows: ESTRO: >50 years, invasive ductal carcinoma/other favourable histology (IDC), T1-2 (≤3 cm), N0, any hormone receptor status, M0; ASTRO: ≥60 years, IDC, T1, N0, positive estrogen hormone receptor status, M0; TARGIT E “elderly”, risk adapted radiotherapy with IORT followed by external beam radiotherapy in case of risk factors in final histopathology. Consecutive patients operated on with the same surgical technique and given IORT were included. Wound complications were evaluated.


2014 ◽  
Vol 32 (2) ◽  
pp. 233-241 ◽  
Author(s):  
F. Fiorini ◽  
D. Neely ◽  
R.J. Clarke ◽  
S. Green

AbstractWe present a new simulation method to predict the maximum possible yield of X-rays produced by electron beams accelerated by petawatt lasers irradiating thick solid targets. The novelty of the method lies in the simulation of the electron refiluxing inside the target implemented with the Monte Carlo code Fluka. The mechanism uses initial theoretical electron spectra, cold targets and refiluxing electrons forced to re-enter the target iteratively. Collective beam plasma effects are not implemented in the simulation. Considering the maximum X-ray yield obtained for a given target thickness and material, the relationship between the irradiated target mass thickness and the initial electron temperature is determined, as well as the effect of the refiluxing on X-ray yield. The presented study helps to understand which electron temperature should be produced in order to generate a particular X-ray beam. Several applications, including medical and security imaging, could benefit from laser generated X-ray beams, so an understanding of the material and the thickness maximizing the yields or producing particular spectral characteristics is necessary. On the other more immediate hand, if this study is experimentally reproduced at the beginning of an experiment in which there is an interest in laser-driven electron and/or photon beams, it can be used to check that the electron temperature is as expected according to the laser parameters.


2018 ◽  
Vol 45 (9) ◽  
pp. 4191-4200 ◽  
Author(s):  
Hao Lei ◽  
Wei Zhang ◽  
Ibrahim Oraiqat ◽  
Zhipeng Liu ◽  
Jun Ni ◽  
...  

2020 ◽  
Vol 13 (8) ◽  
Author(s):  
Solmaz Hashemi ◽  
Seyedmohammadreza Javadi ◽  
Mohammad Esmaeil Akbari ◽  
Hamid Reza Mirzaei ◽  
Seied Rabi Mahdavi

Background: Radiotherapy plays an essential role in breast cancer treatment following breast conserving surgery even in good-risk patients with ductal carcinoma in situ (DCIS) histology. It can be delivered by many techniques, among which is intraoperative radiotherapy (IORT). In recent years, intraoperative radiation therapy has had the same outcome compared with EBRT. Objectives: We studied whether whole breast radiotherapy (WBRT) could safely be replaced by IORT and its ability to control local recurrence like EBRT in pure DCIS. Methods: We assigned 138 patients into the external beam radiotherapy (EBRT), radical, and boost groups. The patients were treated during the last 6 years in the Cancer Research Center of Shahid Beheshti University of Medical Sciences. A total of 57 patients received EBRT, 45 patients received the radical dose of radiotherapy by IORT (36 patients received intraoperative electron radiotherapy [IOeRT] and 9 patients received intraoperative X-ray radiotherapy [IOxRT]) according to the IRIORT consensus protocol, and 36 patients received the boost dose of radiotherapy by IORT (15 patients received IOeRT and 21 patients received IOxRT). The IORT and EBRT groups were compared. The primary endpoint was local recurrence and death and the secondary endpoint was the role of variables in local recurrence. Results: With the mean follow-up of 37 months for the IORT group and 40.1 months for the EBRT group, local recurrence occurred in 8.8% (5 patients), 13.9% (5 patients), and 2.2% (1 patient) of the patients in the EBRT, boost, and radical groups, respectively. Concerning the local recurrence, no significant difference was observed between the radical and EBRT groups (P = 0.058) and between the boost and EBRT groups (P = 0.12). Hazard ratios (HRs) of grade, hormone receptor (HR), tumor size, and age in disease-free survival were evaluated and none of these variables had a significant role in local recurrence. Conclusions: IORT is a good alternative for WBRT in DCIS patients because of its non-inferiority results in comparison with EBRT. Being careful about age, tumor size, biological markers, and margin status is of high importance when using IORT for DCIS.


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