The Effects of the Carbon Fiber Couch of Elekta Infinity Linear Accelerator on Absorbed Dose
Objective To explore the effect of iBEAM evo carbon fiber treatment couch with Elekta Infinity linear accelerator on the absorbed dose of 6 MV X-rays.Methods The Elekta Infinity linear accelerator and a(30×30×10)cm3 solid water phantom with SAD positioning were used for testing,and the beam setting conditions were(10×10)cm2 field,6 MV,and 100 MU.With the measure the reading of the dosimeter with gantry angle of±90°,it was ensured that the water model body was placed in the isocentral position of the linear accelerator,and dosimeter readings were measured and recorded at intervals of 10° from 0° to calculate the attenuation rate of rays at different positions of the linear accelerator treatment bed at different angles.Results With 6 MV X-ray irradiation,the attenuation rate of the main bed of the treatment couch was 1.51%to 5.31%;The attenuation rates at a distance of 3 cm and 7 cm from the connection point of the treatment bed were 0.85%to 35.18%and 0.52%to 17.96%,respectively;The attenuation rates of extension plate 650 and extension plate 415 at the joints with the main bed plate were 1.51%to 27.69%and 0.17%to 27.46%,respectively;The attenuation rates of the extension plate 650 at 3cm and 13cm from the connection junction were 1.29%to 5.65%and 0.35%to 5.29%,respectively.The attenuation rates of the extension plate 415 at 3cm and 13cm from the connection junction were 0.16%to 4.46%and 0.34%to 4.76%,respectively.Conclusions Different positions of the treatment bed have different attenuation rates of radiation,especially the connection area of the main bed plate has a large attenuation rate of radiation.In clinical treatment of patients,appropriate extension plates should be selected according to the situation or the patient's position should be moved to avoid the target area from the connection area.Meanwhile,a suitable treatment bed model should be established in the treatment planning system to reduce the influence of the treatment bed on the absorbed dose of patients.
Treatment bed boardDose attenuationIsocentric positioningAbsorbed dose
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