[Home ] [Archive]    
:: Main :: About :: Current Issue :: Archive :: Search :: Submit :: Contact ::
Main Menu
Home::
IJRR Information::
For Authors::
For Reviewers::
Subscription::
News & Events::
Web Mail::
::
Search in website

Advanced Search
..
Receive site information
Enter your Email in the following box to receive the site news and information.
..
ISSN
Hard Copy 2322-3243
Online 2345-4229
..
Online Submission
Now you can send your articles to IJRR office using the article submission system.
..

AWT IMAGE

AWT IMAGE

:: Search published articles ::
Showing 3 results for Fractionated Radiation

A.s. Meigooni, U. Malik, H. Zhang, S.a. Dini, N. J. Meigooni, K. Komanduri, M. Mohiuddin,
Volume 2, Issue 4 (3-2005)
Abstract

Background:

An effective method for management of large and bulky malignant tumors. This treatment modality is also known as Specially Fractionated Radiation Therapy (SFRT). In this treatment technique a grid block converted the open radiation field into a series of pencil beams. Dosimetric characteristics of an external beam grid radiation field have been investigated using experimental and Monte Carlo simulation technique.

Grid radiation therapy, using the megavoltage X-ray beam, has been proven to be

Materials and Methods:

radiation field have been determined using experimental and Monte Carlo simulation technique, for 6- and 18 MV X-ray beams from a Varian Clinics 2100C/D. The measurements were performed using LiF TLD and film in Solid Water phantom Material. Moreover, the MCNP Monte Carlo code was utilized to calculate the dose distribution in the grid radiation field in the same phantom material. The results of the experimental data were compared to the theoretical values, to validate this technique. Upon the agreement between the two techniques, dose distributions can be calculated for the grid field with different patterns and sizes of holes, in order to find an optimal design of the grid block.

Dose distributions (%DD as well as the beam profiles) of a grid

Results:

simulation technique was in good agreement with the measured data. In addition, the 3D dose distribution of the grid field generated by the Monte Carlo simulation gave more detailed information about the dose pattern of the grid.

The results of dose profiles for 6 MV X-ray beams obtained with the Monte Carlo

Conclusion:

Carlo simulation technique can be utilized to optimize the pattern, size and spacing between the holes, for optimal clinical results.

The grid block can be used as a boost for treatment of bulky tumors. The MonteIran. J. Radiat. Res., 2005 2 (4): 167-174


Dr. Y.a. Zorkina, E.a. Zubkov, Z.i. Storozheva, G.e. Gorlachev, A.v. Golanov, V.p. Chekhonin,
Volume 13, Issue 2 (4-2015)
Abstract

Background: Ionizing radiation causes cognitive impairment in adult brain. However, the effects of various irradiation protocols with fractionated fixed total dose on hippocampal function have not yet been studied. Materials and Methods: Fractionated whole brain irradiation with a total dose of 36 Gy was performed according to the following protocols: 2Gy-18 fractions (2Gy*18), 4Gy-9 fraction (4Gy*9) and 6Gy-6 fractions (6Gy*6). Changes in spatial memory were studied in Morris water maze tests at 12th and 17th day after irradiation with a hidden platform and at 38th day after irradiation without a platform. Levels of expression of brain derived neurotrophic factor (BDNF) and vascular endothelial growth factor (VEGF) genes were evaluated using qPCR. Results: Expression of genes of neurotrophic factors (BDNF and VEGF) was decreased at 4th and 8th week after irradiation, the decrease depended on fractionation. The Morris water maze test with a hidden platform showed improvement in long-term spatial memory at 12th and 17th day after irradiation. In the Morris water maze test without platform cognitive deficit was detected only in 6Gy*6 group at 4th week after irradiation. Conclusion: Our study shows that different fractionation protocols affect hippocampal functions differently, and that the greatest negative impact has the protocol with the maximum single dose. In addition, decrease in expression of genes of neurotrophic factors might play an important role in cognitive impairment.


K. Huang, M. Omura, C. Yan, L. Abdelghany, X. Zhang, M.d., T-S. Li,
Volume 21, Issue 4 (10-2023)
Abstract

Background: Fractionated radiotherapy is widely used for cancer treatment because of its advantages in the preservation of normal tissues; however, it may amplify the radioresistance of cancer cells. In this study, we aimed to understand whether and how fractionated radiation exposure induces radioresistance. Materials and Methods: HCT8 human colorectal cancer cells received a total X-ray dose of 5 Gy in either a single treatment (5 Gy administered once) or via fractionated exposure (1 Gy/day treatment for 5 consecutive days). We then examined the radioresistance of cancer cells exposed an additional 2 Gy X-ray by clonogenic assay and Western blot analysis. Results: Cells receiving fractionated exposure showed significantly greater proliferation and clonogenicity than those that received a single dose. Compared with the levels in the intact cells without radiation exposure, the expression levels of γH2AX, phospho-ATM and PARP were significantly enhanced only in the cells exposed to fractionated radiation. In contrast, the expression of cyclin D1 and cyclin E1 was enhanced only in the cells that received a single dose. In addition, the expression of SOD1 and SOD2 was slightly increased in the cells that received either the fractionated exposure or single exposure treatment. Conclusions: Fractionated radiation exposure facilitates radioresistance in HCT8 human colorectal cancer cells predominantly by enhancing their DNA repair capacity.


Page 1 from 1     

International Journal of Radiation Research
Persian site map - English site map - Created in 0.07 seconds with 39 queries by YEKTAWEB 4714