Book ChapterDOI
Evaluation of dosimetric characteristics of a grid block fabricated for Mega-voltage grid therapy purposes
TLDR
The measured dosimetric characteristics of grid block indicate that the mega-voltage grid therapy can be applied as a possible clinical modality for palliative cases.Abstract:
In conventional radiation therapy, regarding normal tissue tolerance, the treatment of bulk tumors is one of the remaining challenges. In order to cope with, Grid Radiation Therapy (GRT) is a technique to deliver high doses, approximately 15 - 20 Gy per fraction, to several small volumes located in a large radiation field. This can be performed using a grid block. The current work concentrates on the dosimetric characteristics of a designed mega-voltage grid, used for a unique treatment modality. A square 16 × 16 array grid block was designed and fabricated. Several dosimetric characteristics including: depth dose, Valley To Peak (VTP) ratio, and grid out-put factor were evaluated using a calibrated diode dosimeter for a range of radiation fields. The percent depth dose curves, measured in the presence of grid block, lie within those measured for the corresponding open field and a narrow beam. At the Dmax, the VTP ratio was fond to be within 17% -28%, while these ranges between 23% - 35% at a depth of 10 cm. The grid out-put factor found to be 0.78 and it slightly decreases with increasing of radiation field size. The measured dosimetric characteristics of grid block indicate that the mega-voltage grid therapy can be applied as a possible clinical modality for palliative cases.read more
Citations
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Journal ArticleDOI
Non-linear adaptive phenomena which decrease the risk of infection after pre-exposure to radiofrequency radiation
Seyed Mohammad Javad Mortazavi,Mohammad Motamedifar,G. Namdari,Mohammad Taheri,A.R. Mortazavi,Nasrin Shokrpour +5 more
TL;DR: The findings contribute to the assumption that radiofrequency-induced adaptive response can be used as an efficient method for decreasing the risk of infection in immunosuppressed irradiated individuals.
Journal ArticleDOI
The effect of combined exposure of 900 MHz radiofrequency fields and doxorubicin in HL-60 cells.
TL;DR: RF pre-exposure appear to protect the HL-60 cells from the toxic effects of subsequent treatment with doxorubicin, similar to earlier data which suggested that pre-Exposure of mice to 900 MHz RF had a protective effect in hematopoietic tissue damage induced by subsequent gamma-irradiation.
Journal ArticleDOI
Adaptive response in mammalian cells exposed to non-ionizing radiofrequency fields: A review and gaps in knowledge.
TL;DR: Observations suggested the ability of radiofrequency fields to induce adaptive response and also indicated some potential mechanisms for the induction of such response.
Journal ArticleDOI
Induction of an adaptive response in human blood lymphocytes exposed to radiofrequency fields: Influence of the universal mobile telecommunication system (UMTS) signal and the specific absorption rate
Olga Zeni,Anna Sannino,Stefania Romeo,Rita Massa,Maurizio Sarti,Abishek B. Reddy,Thomas J. Prihoda,Vijayalaxmi,Maria Rosaria Scarfì +8 more
TL;DR: Overall data suggest that the induction of AR depends on RF frequency, type of the signal and SAR, and further characterization of RF-induced AR is in progress.
Journal ArticleDOI
Adaptive response in mice exposed to 900 MHz radiofrequency fields: primary DNA damage.
TL;DR: RF pre-exposure is capable of inducing adaptive response in mice exposed to non-ionizing radiofrequency fields and it is suggested that the pre-Exposure for more than 4 hours for 1 day is necessary to elicit such AR.
References
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Journal ArticleDOI
Adaptive Response of Human Lymphocytes to Low Concentrations of Radioactive Thymidine
TL;DR: When human lymphocytes were cultured with [3H]thymidine, which acts as a source of low-level chronic radiation, and then exposed to 150 rad of x-rays at 5, 7, 9, or 11 hours before fixation, the yield of chromatid aberrations was less than the sum of the yields of aberration induced by [3 H]thcyidine and x-ray separately.
Journal ArticleDOI
Mammalian lignan production from various foods
TL;DR: Lignan production with the in vitro method related well to the urinary lignan excretion observed in rats and humans and should be useful in the estimation of lignans production from a given diet and in the formulation of high-lignan-producing diet for the purpose of reducing the cancer risk.
Journal ArticleDOI
Lignans and Human Health
TL;DR: Evidence suggests that fiber- and lignan-rich whole-grain cereals, beans, berries, nuts, and various seeds are the main protective foods.
Journal ArticleDOI
Very high background radiation areas of Ramsar, Iran: preliminary biological studies.
TL;DR: Inhabitants of high background radiation areas had about 56% the average number of induced chromosomal abnormalities of normal background radiation area inhabitants following this exposure, which suggests that adaptive response might be induced by chronic exposure to natural background radiation as opposed to acute exposure to higher levels of radiation in the laboratory.
Journal ArticleDOI
Human lymphocytes exposed to low doses of ionizing radiations become refractory to high doses of radiation as well as to chemical mutagens that induce double-strand breaks in DNA.
TL;DR: The results indicate that prior exposure to 0.01 Gy of X-rays reduces the number of chromosome breaks induced by double-strand breaks, and perhaps even by cross-links, in DNA, but has the opposite effect on breaks inducing by the alkylating agent MMS.