Method for measuring and detecting beam dosage distribution

Abstract

The invention discloses a method for measuring and detecting beam dosage distribution. The method comprises following steps that S1, a computer detects a beam signal and judges the state of the beam, if the beam is in the starting state, the step 2 is entered and if the beam is in the closed state, the step 3 is entered; step 2, a detector module detects second gamma photon, and transmits a detected second gamma photon signal to the computer; S3, the detector module carries out positive electronic mode detection and transmits a detected positive electrode mode signal to the computer; and step 4, the computer carries out signal processing on the second gamma photon signal and the positive electronic mode signal which are obtained through detection, and obtains spatial distribution of the beam dosage. According to the invention, distribution of the beam dosage after the beam is after the beam passes through a simulated human body, so emission dosage of a beam emission end is further detected and accuracy of the detected dosage distribution is judged.

Description

Technical field [0001] The invention belongs to the technical field of dose verification equipment, and in particular relates to a method for measuring and detecting beam dose distribution. Background technique [0002] The principle of preoperative dose verification is to use a phantom instead of the patient, irradiate the proton / heavy ion terminal with a designed treatment plan, and actually measure the spatial distribution of the proton beam / heavy ion beam dose in the phantom, and compare it to expectations Comparing the spatial distribution of, verify whether there is a deviation to ensure that the accelerator is working in a normal state. [0003] The basic technical route for intraoperative and postoperative dose verification of proton / heavy ion therapy is positron emission tomography (PET). The principle of this technical route is as follows: where protons / heavy ions deposit doses after entering the human body, they will react with the nuclei in the human body to generate p...

AI Technical Summary

Problems solved by technology

This measurement has three main disadvantages: First, due to the movement of the patient's body, soft tissues and organs have already undergone displacement and deformation compared with the treatment, so the PET image needs to be processed with complex registration processing with the CT image of the treatment terminal. Increased the difficulty of measurement result processing while reducing measurement accuracy

The second is that it takes a certain amount of time (about 20 minutes) from the end of the treatment to the PET scan. At this time, 15O (half-life of 2 minutes) basically decays, and most of 13N (half-life of 10 minutes) decays, so only part of it can be measured. 11C (half-life 20 minutes) information, lost valuable information

Third, the reconstruction algorithms used in clinical PET are all designed for the injection of positron drugs (positron activity is in the mCi order), and cannot be well applied to patients with low positron activity after proton / heavy ion therapy. However, the imaging error is large, which reduces the accuracy of the measurement

Even when this technology matures, it will be very expensive

[0005] At present, the dose measurement instrument used for intraoperative verification is mainly online PET, which is installed on the proton / heavy ion therapy terminal to measure while irradiating. It is necessary to build a large ring detector, which is bulky and expensive, and has not yet been widely used in clinical practice. application

And it is not real-time online measurement, real synchronization cannot be achieved, and PET scan is required after the treatment, which takes a long time

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