Method for correcting individual computed tomography (CT) value in cone beam CT image for calculation of radio treatment dose

Abstract

The invention discloses a method for correcting an individual computed tomography (CT) value in a cone beam CT image for calculation of a radio treatment dose. The method comprises the following steps of: (1) establishing mapping relationship from a CT value of a fan beam CT image to an electron density value of an imaging target; (2) acquiring cone beam and fan beam CT images; (3) segmenting theoverlapped areas of the cone beam and fan beam CT images into N levels of local areas; (4) acquiring an individual multi-level CT value correction table; (5) correcting the cone beam CT image which is acquired sequentially by using the individual CT value correction table; and (6) calculating the radio treatment dose by using the mapping relationship in the step (1). The information of the cone beam CT image is quickly and conveniently converted into the electron density information by using the method for correcting the CT value, so that the cone-beam-CT-image-based radio treatment dose calculation is realized; by establishing the multi-level CT value correction table, the CT value correction information is more accurate and perfect; the multi-level CT value correction table is established based on a specific anatomical structure of a patient, so that the CT value correction process is more accurate.

Description

technical field [0001] The present invention relates to an individualized CT value correction method for cone-beam CT images used in radiotherapy dose calculation, more specifically, to a method for utilizing fan-beam CT value-electron density value mapping relationship and individualized CT value correction table A method for obtaining electron density values ​​from cone-beam CT images and using them for dose calculations. Background technique [0002] Modern radiotherapy techniques, such as three-dimensional conformal radiotherapy and intensity-modulated radiotherapy, usually rely on fan-beam CT scans to complete radiotherapy positioning and formulate radiotherapy plans accordingly. This is because there is a relatively stable mapping relationship between the CT value of the positioning fan beam CT image and the electron density of the imaging target. This mapping relationship is usually determined in advance and stored in the radiotherapy planning system, so that after t...

AI Technical Summary

Problems solved by technology

However, accurate 3D image registration usually requires a large amount of calculation and a long calculation time. At the same time, depending on the selected registration algorithm and the registration target change response in fan-beam CT and cone-beam CT images Different degrees of difficulty of registration will produce different degrees of registration error. Larger registration errors require further manual adjustment, which takes more time. Therefore, the time for patients lying on the treatment bed waiting for treatment It is very difficult to complete online field adjustment or replanning by precise image registration

Images