Ion Beam Depth Modulation for Target Volume Movement Compensation
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Solution Overview
Problem
Conventional ion beam irradiation systems struggle to accurately compensate for three-dimensional movements of a target volume during treatment, leading to inadequate dose distribution and homogeneity due to slow longitudinal adjustments and sensitivity to changes in tissue density and composition, especially during patient movement.
Innovation Solution
An apparatus with a position location and tracking system, coupled with a movement measurement, control, and read-out module, and a depth modulator, uses real-time data from ultrasound or X-ray images to vectorially break down target volume movements and adjust the ion beam's depth penetration and transverse deflection, ensuring precise compensation and dose homogeneity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional raster scanning method is used for ion beam irradiation, then transverse corrections can be made in fractions of milliseconds, but longitudinal settings can be changed only in synchronicity with the accelerator cycle, resulting in very slow response to target volume movements
Solution Approach 1:
The correction system is segmented into two independent components: transverse correction handled by the raster scanning apparatus and longitudinal correction handled by the depth modulator. This allows each component to operate at its optimal speed without being constrained by the other, resolving the contradiction between fast transverse response and slow longitudinal response.
Solution Approach 2:
A control unit acts as an intermediary that receives movement information from a position location system and independently controls both the raster scanning apparatus and the depth modulator. This intermediary coordinates the two correction mechanisms, enabling synchronized transverse and longitudinal corrections with fast response times.
2Manufacturing precision
If ion beam energy is increased to penetrate deeper tissue, then dose escalation occurs in the target volume, but changes in healthy tissue density and composition cause dose distribution to shift, missing the target volume
Solution Approach 1:
The system incorporates a position location and tracking system that continuously monitors target volume position and provides real-time movement information to the control unit. This feedback loop enables dynamic adjustment of beam energy and depth of penetration to compensate for tissue density changes and maintain precise dose delivery to the moving target volume.
Solution Approach 2:
The depth modulator dynamically adjusts the depth of penetration of the ion beam in real-time based on detected target volume movements and tissue density changes. This dynamic adaptation allows the system to maintain precise dose delivery despite variations in healthy tissue composition and density.
3Measurement precision
If patient movement is detected using precision video cameras, then longitudinal displacement can be detected, but exact beam modification or correction cannot be carried out from beam position to beam position
Solution Approach 1:
The system replaces mechanical beam adjustment mechanisms with electronic control of the raster scanning apparatus and depth modulator. The control unit processes position information from video cameras and automatically generates correction signals, enabling exact beam modification from beam position to beam position without manual intervention or complex mechanical adjustments.
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 solution enables high-precision irradiation of moving target volumes by dynamically adjusting the ion beam in all three spatial directions, maintaining dose homogeneity comparable to static conditions, even during patient movement, thus improving therapy success and patient comfort.
Implementation Method 1
real-time data from ultrasound or X-ray images
Implementation Method 2
real-time data from ultrasound or X-ray images
Implementation Method 3
depth modulator, by means of which the depth of penetration of the ion beam can be re-adjusted
Implementation Method 4
raster scanning apparatus, which makes possible transverse deflection of the ion beam in fractions of milliseconds
Data Source
AI summary
The invention relates to an apparatus and method for compensation of three-dimensional movements of a target volume (1) during ion beam irradiation. For the purpose, the apparatus comprises a position location and tracking system (4) for detecting the movements and a depth modulator (6) for modifying the depth of penetration of the ion beam. For the purpose of compensation, the movements are divided vectorially into a transverse component and a longitudinal component. The transverse component is compensated from irradiation point to irradiation point using the raster scanning apparatus (3) and the longitudinal component is compensated from irradiation point to irradiation point using the depth modulator (6) by means of the fact that, in addition to the change in the location of the target volume, the change in the structure of healthy tissue covering the target volume is, in the preliminaries to irradiation, detected and modelled and stored in the form of a look-up table in a memory of a movement measurement, control and read-out module SAMB and compared with the actual values during irradiation.