Effect of DNA Synthesis Inhibitors on the Biological Efficiency of a Proton Beam in a Modified Bragg Peak

2019 ◽  
Vol 16 (2) ◽  
pp. 153-158
Author(s):  
E. A. Krasavin ◽  
A. V. Boreyko ◽  
M. G. Zadneprianetc ◽  
E. V. Ilyina ◽  
R. A. Kozhina ◽  
...  
Keyword(s):  
Dna Synthesis ◽  
Proton Beam ◽  
Bragg Peak ◽  
Biological Efficiency ◽  
Dna Synthesis Inhibitors

BIOLOGICAL EFFICIENCY OF THE PROTON SCANNING BEAM OF THE THERAPEUTIC COMPLEX "PROMETHEUS" OF THE A.F. TSYB MEDICAL RADIOLOGICAL RESEARCH CENTER IN STUDIES ON CELL CULTURE OF MURINE MELANOMA B-16

2018 ◽  
Vol 64 (5) ◽  
pp. 678-682
Author(s):  
Yevgeniy Beketov ◽  
Olga Lepilina ◽  
Vyacheslav Saburov ◽  
Aleksandr Chernukha ◽  
Liliya Ulyanenko ◽  
...  
Keyword(s):  
Cell Culture ◽  
Proton Beam ◽  
Bragg Peak ◽  
Quadratic Model ◽  
Biological Efficiency ◽  
Proton Radiation ◽  
Linear Quadratic ◽  
Linear Quadratic Model ◽  
Number Of Factors ◽  
60Co Gamma

The basis for the use of protons for radiation therapy tasks is a fixed conventional value of their relative biological efficiency equal to 1,1. Numerous studies have showed that RBE of proton radiation is not a constant value and depends on a number of factors. The purpose of this study was to determine RBE of a thin scanning proton beam at the center of the distributed Bragg peak in experiments on the culture of murine B-16 melanoma cells. The cell suspension was irradiated in an aqueous phantom by a horizontal proton beam from three directions (0,90 and 180°) in doses from 2 to 8 Gy. Modulation of the energy of proton radiation was 47,5÷92,0 MeV. RBE protons were determined from the clonogenic activity of the cells compared with 60Co gamma quanta. A linear-quadratic model was used to construct the dose dependencies. Obtained RBE values of proton radiation (LET 3÷8 keV/μm) differed in the big party from the generally accepted value and was at the level of 10% survival rate of 1.5. The results obtained generally coincided with data of foreign authors performed on different facilities.

An MCNPX2.7.0 study of Bragg peak degradation owing to density heterogeneity patterns for a CGMH therapeutic proton beam

2017 ◽  
Vol 137 ◽  
pp. 121-124 ◽  
Author(s):  
Tsi-Chian Chao ◽  
Yi-Chun Tsai ◽  
Shih-Kuan Chen ◽  
Shu-Wei Wu ◽  
Chuan-Jong Tung ◽  
...  
Keyword(s):  
Proton Beam ◽  
Bragg Peak

scholarly journals Transitions of Liver and Biliary Enzymes during Proton Beam Therapy for Hepatocellular Carcinoma

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1840
Author(s):  
Taisuke Sumiya ◽  
Masashi Mizumoto ◽  
Yoshiko Oshiro ◽  
Keiichiro Baba ◽  
Motohiro Murakami ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Proton Beam ◽  
Liver Damage ◽  
Bragg Peak ◽  
Total Bilirubin ◽  
Normal Liver ◽  
Proton Beam Therapy ◽  
Gamma Glutamyl Transpeptidase ◽  
Preserve Liver Function ◽  
Glutamyl Transpeptidase

Proton beam therapy (PBT) is a curative treatment for hepatocellular carcinoma (HCC), because it can preserve liver function due to dose targeting via the Bragg peak. However, the degree of direct liver damage by PBT is unclear. In this study, we retrospectively analyzed liver/biliary enzymes and total bilirubin (T-Bil) as markers of direct liver damage during and early after PBT in 300 patients. The levels of these enzymes and bilirubin were almost stable throughout the treatment period. In patients with normal pretreatment levels, aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT), and T-Bil were abnormally elevated in only 2 (1.2%), 1 (0.4%), 0, 2 (1.2%), and 8 (3.5%) patients, respectively, and in 8 of these 13 patients (61.5%) the elevations were temporary. In patients with abnormal pretreatment levels, the levels tended to decrease during PBT. GGT and T-Bil were elevated by 1.62 and 1.57 times in patients who received 66 Gy (RBE) in 10 fractions and 74 Gy (RBE) in 37 fractions, respectively, but again these changes were temporary. These results suggest that direct damage to normal liver caused by PBT is minimal, even if a patient has abnormal pretreatment enzyme levels.

scholarly journals The Radiobiological Effects of Proton Beam Therapy: Impact on DNA Damage and Repair

Cancers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 946 ◽  
Author(s):  
Eirini Terpsi Vitti ◽  
Jason L Parsons
Keyword(s):  
Dna Damage ◽  
Dna Repair ◽  
Proton Beam ◽  
Bragg Peak ◽  
Proton Beam Therapy ◽  
High Energy ◽  
High Let ◽  
Repair Pathways ◽  
Radiobiological Effects ◽  
Photon Radiotherapy

Proton beam therapy (PBT) offers significant benefit over conventional (photon) radiotherapy for the treatment of a number of different human cancers, largely due to the physical characteristics. In particular, the low entrance dose and maximum energy deposition in depth at a well-defined region, the Bragg peak, can spare irradiation of proximal healthy tissues and organs at risk when compared to conventional radiotherapy using high-energy photons. However, there are still biological uncertainties reflected in the relative biological effectiveness that varies along the track of the proton beam as a consequence of the increases in linear energy transfer (LET). Furthermore, the spectrum of DNA damage induced by protons, particularly the generation of complex DNA damage (CDD) at high-LET regions of the distal edge of the Bragg peak, and the specific DNA repair pathways dependent on their repair are not entirely understood. This knowledge is essential in understanding the biological impact of protons on tumor cells, and ultimately in devising optimal therapeutic strategies employing PBT for greater clinical impact and patient benefit. Here, we provide an up-to-date review on the radiobiological effects of PBT versus photon radiotherapy in cells, particularly in the context of DNA damage. We also review the DNA repair pathways that are essential in the cellular response to PBT, with a specific focus on the signaling and processing of CDD induced by high-LET protons.

Sign in / Sign up

Export Citation Format

Share Document