Gamma Ray Shield Slits for Particle Beam Position Resolution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional particle beam systems face challenges in measuring the position irradiated with charged particle beams with sufficient sensitivity and spatial resolution.
Innovation Solution
A gamma ray detector with multiple detection elements is disposed along the particle beam's travel direction, and a shield with multiple transmission portions is placed between the irradiation axis and the detector. The system estimates the Bragg peak by analyzing the count value distribution of gamma rays passing through the transmission portions and detected by the elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the width of the gap between collimators is increased to improve sensitivity to immediate gamma rays, then measurement sensitivity is improved, but spatial resolution of the irradiated position is reduced
Solution Approach 1:
The shield is divided into multiple transmission portions (collimators) arranged in the depth direction. Each transmission portion corresponds to a specific depth region, allowing gamma rays from different depths to be spatially separated and detected by different detection elements. This segmentation enables simultaneous achievement of high sensitivity (through multiple transmission portions) and high spatial resolution (through depth-dependent spatial separation of gamma ray paths).
Solution Approach 2:
The invention transitions from a single-dimension measurement approach to a two-dimension detection approach. By arranging transmission portions and detection elements in the depth direction (z-axis) and detecting gamma rays at positions along the irradiation axis (x-axis), the system creates a correspondence between depth position and detection position. This dimensional mapping allows gamma rays from different depths to be distinguished by their detection positions, achieving high spatial resolution while maintaining sensitivity through multiple detection channels.
2Measurement precision
If a gamma ray pinhole camera or collimator-based gamma camera is used to measure dose distribution in the depth direction, then the Bragg peak position can be determined, but measurement sensitivity and spatial resolution are insufficient
Solution Approach 1:
The shield with transmission portions acts as an intermediary optical element between the gamma ray source (irradiation site) and the detector. It selectively transmits gamma rays from specific depth regions while blocking others, creating a spatially resolved gamma ray distribution on the detector that corresponds to the depth distribution of the particle beam. This intermediary structure enables precise Bragg peak determination without the sensitivity and resolution limitations of conventional pinhole or collimator-based cameras.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances measurement sensitivity and spatial resolution, allowing for accurate confirmation of the particle beam's irradiation position, which improves treatment efficiency and expands the application of particle therapy.
Implementation Method 1
when the particle beam travels inside the irradiation target, immediate gamma rays are generated by collision between the particle beam and atoms inside the irradiation target
Implementation Method 2
a shield in which a plurality of transmission portions of the gamma ray are provided along the traveling direction of the beam is disposed between the irradiation axis and the gamma ray detector
Implementation Method 3
a gamma ray detector in which a plurality of detection elements are disposed along a traveling direction of a particle beam
Data Source
AI summary
An object of the present invention is to increase sensitivity and position resolution of measurement of an arrival position of a charged particle beam irradiated during treatment. A beam monitoring system includes: a gamma ray detector that detects gamma rays generated by interaction between a charged particle beam and an irradiation target; a shield that is disposed between the gamma ray detector and an irradiation axis of the beam and has a plurality of slits; and a calculation unit that analyzes a detection result of the gamma ray detector and reconfigures a count distribution of the detected gamma rays into a distribution of the beam irradiation axis based on a geometric arrangement of the shield, the detector, and the irradiation axis of the beam. The calculation unit obtains the arrival position of the particle beam from the reconfigured distribution.