Radiotherapy Posture Tracking Bed for Respiratory Tumor Alignment
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Solution Overview
Problem
Existing radiotherapy systems face challenges in accurately irradiating tumor targets due to patient weight loss, irregular body contour changes, and respiratory motion, leading to poor fixation, increased normal tissue exposure, and low radiation utilization efficiency.
Innovation Solution
A real-time human posture tracking and calibration system using a matrix of telescopic support rods with non-metallic support balls and millimeter-wave detection, allowing for precise adjustment of patient posture through a U-shaped base and gear-driven rotation, compensating for real-time displacement of tumor targets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional posture fixation devices (thermoplastic film, foam rubber, vacuum bags) are used to fix the tumor area, then patient posture can be stabilized during irradiation, but gaps form with the body surface when patients experience weight loss and body contour changes, resulting in poor fixation accuracy
Solution Approach 1:
The patent employs a six-dimensional treatment bed with dynamic adjustment capabilities that can real-time compensate for body contour changes and respiratory motion. The bed allows independent adjustment of patient position in six degrees of freedom (three translational and three rotational movements), enabling continuous adaptation to changing body geometry throughout the treatment course, thereby maintaining reliable fixation without gaps even when patients experience weight loss.
Solution Approach 2:
The system changes the parameter of posture fixation from static traditional devices to dynamic adjustable positioning. The treatment bed can adjust multiple positional parameters (x, y, z translations and pitch, roll, yaw rotations) to match the patient's current body contour, transforming the fixation system from rigid and static to flexible and adaptive.
2Reliability
If the irradiation field is expanded to ensure the tumor's movement range remains within the field, then the tumor target area can be consistently irradiated, but the dose to normal tissues increases, raising the probability of normal tissue complications
Solution Approach 1:
The patent implements real-time feedback through imaging guidance systems that continuously monitor tumor position and body contour changes. The treatment bed adjusts patient positioning based on this feedback, keeping the tumor precisely within the irradiation field without requiring field expansion. This closed-loop control ensures reliable tumor coverage while minimizing normal tissue exposure by adapting to actual tumor position rather than using a fixed expanded field.
Solution Approach 2:
The system dynamically adjusts the irradiation field positioning to match the tumor's actual position in real-time, rather than using a static expanded field. The six-dimensional treatment bed enables continuous positional adjustments to keep the moving tumor target within the optimal irradiation zone, reducing the need for excessive field margins.
3Measurement precision
If gated radiotherapy is used to stop the radiation beam when the tumor position is off-target, then the tumor can be accurately targeted, but radiation utilization efficiency decreases and treatment time increases
Solution Approach 1:
The patent performs preliminary positioning adjustments using the six-dimensional treatment bed before radiation delivery begins. By pre-adjusting the patient position to account for predicted tumor movement (based on respiratory phase or body contour changes), the system eliminates the need for repeated beam interruptions. The tumor is proactively kept within the irradiation field through anticipatory positioning rather than reactive beam gating.
4Measurement precision
If a six-dimensional treatment bed is used to correct positioning errors through online adjustments, then tumor position accuracy can be improved, but the system complexity increases and requires precise initial fixation
Solution Approach 1:
The patent segments the positioning correction function into two parts: traditional fixation devices provide initial coarse stabilization, while the six-dimensional treatment bed provides fine precision adjustment. This segmentation allows each component to perform its specialized function optimally - the simple initial fixation and the complex refined positioning - reducing the overall system complexity burden while achieving high accuracy.
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
Ensures precise tumor target irradiation by maintaining the tumor within the irradiation field, reducing normal tissue exposure, and improving radiation efficiency without expanding the field, thus enhancing treatment efficacy.
Implementation Method 1
the foot of the treatment bed is equipped with a millimeter-wave detector, the millimeter-wave detector is capable of scanning all the support balls by emitting millimeter waves to detect a spatial position of each of the support balls
Data Source
AI summary
A real-time human posture tracking and calibration device and a system for tumor radiotherapy are provided, which may replace the traditional treatment bed of a linear accelerator. For tumor targets in areas such as the head and neck that do not move with respiration, the system tracks changes in the skin external contour and the static position of the tumor. For tumors in the chest and abdomen that are significantly affected by respiration, the system first tracks changes in the skin external contour and then compensates for the displacement of the tumor target moving with respiration.