Accelerator radiant matter measurement method

Abstract

The invention relates to an accelerator radiant matter measurement method. The measurement method comprises the steps of disposing an ionization chamber in a water tank, wherein the axial direction ofthe ionization chamber is perpendicular to the bottom face of the water tank; adjusting the angle of a machine head of an accelerator, so that the direction of ray beams emitted by the accelerator isperpendicular to the axial direction of the ionization chamber; turning on the accelerator and a water tank system controller, and controlling the ionization chamber or the water tank to move from afirst position to a second position in the direction of the ray beams through the water tank system controller; measuring the percent depth dose PDDx and the percent depth dose PDDy of the ray beams corresponding to the first position and the second position in the water tank through a dosimeter, wherein x and y are thicknesses of water molds corresponding to the first position and the second position respectively; changing a dose rate value of the accelerator or changing a set dose MU for performing multiple groups of tests to obtain multiple groups of PDDx and PDDy; performing calculation according to PDDx and PDDy to obtain multiple groups of radiant matter indexes, wherein the radiant indexes are tissue phantom ratios TPRx and TPRy.

Description

technical field [0001] The invention relates to the field of measurement, in particular to a method for measuring accelerator radiation quality. Background technique [0002] In the field of measurement, about 90% of medical accelerators are electron linear accelerators, which produce high-energy photons for cancer treatment by accelerating electrons to target. Accelerators are calibrated for high-energy photons at 4MV, 6MV, 8MV, 10MV, 10MV, 12MV, 15MV, 18MV, 20MV, 21MV, and 25MV. This calibration is incomplete in clinical radiation therapy, and it is specific to each nominal value. The penetration ability of X-rays irradiated by different accelerators is different. Even for the same manufacturer and the same type of accelerator, the ray penetration ability produced by each nominal value is not exactly the same. The radiation quality of high-energy X-rays emitted by accelerators is usually described by the radiation quality index. Radiation quality index using tissue phan...

AI Technical Summary

Problems solved by technology

[0003] The current measurement methods for high-energy photon radiation quality of accelerators include dose ratio (D20 / D10) formula calculation method and tissue phantom ratio (TPR 20,10 ) direct experiment method, commonly used dosimeters and small water tanks to adjust the water depth to measure point by point, and the measurement and calculation workload is large and the error is large

Images