Synonymous point mutation of gtfB gene caused by therapeutic X-rays exposure reduced the biofilm formation and cariogenic abilities of Streptococcus mutans.

Background: The shift of oral microbiota is a critical factor of radiation caries in head and neck cancer patients after the radiotherapy. However, the direct effects of irradiation on the genome and virulence of cariogenic bacteria are poorly described. Here we investigated the genomic mutations and virulence change of Streptococcus mutans (S.

Error analysis of applicator position for combined internal/external radiation therapy in cervical cancer.

The aim of this study was to analyze the error variation in the applicator placement during the first and second radiotherapy session for cervical cancer. We recruited 22 patients with cervical cancer treated with radiotherapy. According to the image output in the first and second CT-Sim inspection, we conducted comparative analysis of image fusion to accurately measure the errors in applicator position in the horizontal (X-), longitudinal (Y-) and vertical (Z)-axes.

Preliminary clinical study on brass compensator-based intensity-modulated radiation therapy.

Objective: The objective of this study is to preliminarily evaluate the feasibility of brass compensator-based intensity-modulated radiation therapy (CB-IMRT).

Materials And Methods: Ten patients (three cases of nasopharyngeal cancer, four of esophageal cancer, and three of rectal cancer) who underwent an IMRT treatment planning were selected for this study. The transmission coefficient of brass plates with different thicknesses was measured under a 6 MV photon beam used in the treatment planning system, and the equation for thickness computation was fitted out.

A clinical study of lung cancer dose calculation accuracy with Monte Carlo simulation.

Background: The accuracy of dose calculation is crucial to the quality of treatment planning and, consequently, to the dose delivered to patients undergoing radiation therapy. Current general calculation algorithms such as Pencil Beam Convolution (PBC) and Collapsed Cone Convolution (CCC) have shortcomings in regard to severe inhomogeneities, particularly in those regions where charged particle equilibrium does not hold. The aim of this study was to evaluate the accuracy of the PBC and CCC algorithms in lung cancer radiotherapy using Monte Carlo (MC) technology.

Effects of lysophosphatidic acid and its receptors LPA⅓ on radiation pneumonitis.

Radiation pneumonitis (RP) is a serious complication of radiation therapy for thoracic tumors. Lysophosphatidic acid (LPA) and its receptors LPA⅓ were reported to participate in the processes of inflammation. We tested the hypothesis that LPA and its receptors LPA⅓, take part in the pathogenesis of RP.