We consider the fractionation problem in radiation therapy. Tumor sites in which the dose-limiting organ at risk (OAR) receives a substantially lower dose than the tumor, bear potential for hypofractionation even if the α/β-ratio of the tumor is larger than the α/β-ratio of the OAR. In this work, we analyze the interdependence of the optimal fractionation scheme and the spatial dose distributio...

the present work was designed to study the antioxidant activity and to identify the main active components of the essential oil of ajowan (trachyspermum copticum) fruit. gc and gc-ms analyses of the essential oil showed the presence of eight compounds. the main constituents of the oil were thymol (43.7%), p-cymene (26.8%), and γ-terpinene (24.9%). the antioxidant and free radical scavenging act...

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 (...

PURPOSE The aim of this work was to compare value of doses calculated in healthy tissues according to chosen different HDR brachytherapy (HDRBT) fractionation schemas with doses given once and twice daily. MATERIAL AND METHODS Fifty one patients with head and neck cancers, brain tumors, breast cancers, sarcoma, penile cancer and rectal cancer were qualified for calculations. Doses were calcul...

PURPOSE To investigate the clinical implications of a variable relative biological effectiveness (RBE) on proton dose fractionation. Using acute exposures, the current clinical adoption of a generic, constant cell killing RBE has been shown to underestimate the effect of the sharp increase in linear energy transfer (LET) in the distal regions of the spread-out Bragg peak (SOBP). However, experi...

Total body irradiation/Pulmonary complications/Dose fractionation. Total body irradiation (TBI) is an important component of conditioning regimens for Allogeneic bone marrow transplantation (BMT). Interstitial pneumonitis (IP) and other pulmonary disorders are known regimen-related complications. The incidence of IP is related to the dose rate and dose fractionation; however, there is a paucity...

BACKGROUND AND PURPOSE Relative to X-ray beams, proton [(1)H] and carbon ion [(12)C] beams provide superior distributions due primarily to their finite range. The principal differences are LET, low for (1)H and high for (12)C, and a narrower penumbra of (12)C beams. Were (12)C to yield a higher TCP for a defined NTCP than (1)H therapy, would LET, fractionation or penumbra width be the basis? ...

The present work was designed to study the antioxidant activity and to identify the main active components of the essential oil of ajowan (Trachyspermum copticum) fruit. GC and GC-MS analyses of the essential oil showed the presence of eight compounds. The main constituents of the oil were thymol (43.7%), p-cymene (26.8%), and γ-terpinene (24.9%). The antioxidant and free radical scavenging act...