Strap-Based Head Immobilization with Force Gauges
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Solution Overview
Problem
Current immobilization devices for radiation therapy, such as thermoplastic masks, are uncomfortable and restrictive, causing anxiety in patients, particularly those with claustrophobia, and are not adaptable to changes in patient anatomy due to weight loss or tumor shrinkage, leading to unreliable positioning and increased treatment costs.
Innovation Solution
A head and neck immobilization device using straps with force gauges that apply precise and replicable forces to position the patient, eliminating the need for masks and allowing control over neck extension, ensuring consistent positioning for radiation therapy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermoplastic mask is used to immobilize the patient's head, then the positioning reliability is improved, but the patient comfort deteriorates and anxiety increases
Solution Approach 1:
The mask is divided into multiple independent straps (first strap over forehead, second strap over chin, third strap over nose) that can be adjusted separately. Each strap is connected to force gauges that can be independently calibrated, allowing the system to maintain reliable positioning while improving comfort through segmented, adjustable components rather than a single restrictive mask structure.
2Reliability
If a thermoplastic mask is used to immobilize the patient's head, then the positioning reliability is improved, but the adaptability to anatomical changes deteriorates
Solution Approach 1:
The system uses adjustable straps with force gauges that can be recalibrated to match new anatomical positions. When weight loss or tumor shrinkage occurs, the force gauges can be re-calibrated to the new strap lengths and tensions, allowing the system to adapt to anatomical changes while maintaining positioning reliability. This dynamic recalibration capability replaces the static, non-adjustable nature of traditional masks.
Solution Approach 2:
The force applied by each strap is a controllable parameter that can be adjusted via the force gauges. When anatomical changes occur, the force parameters can be modified to compensate for changes in head shape or size, maintaining effective positioning. The system transitions from fixed geometric constraints to adjustable force parameters that can adapt to various anatomical configurations.
3Measurement precision
If a thermoplastic mask is used to immobilize the patient's head, then the positioning precision is improved, but the device complexity increases
Solution Approach 1:
The complex thermoplastic mask structure is replaced with a simpler mechanical system of straps and force gauges. The force gauges provide precise measurement of the force applied by each strap, enabling accurate positioning control through mechanical means rather than relying on the complex molded structure of a thermoplastic mask. This substitution reduces device complexity while maintaining or improving positioning precision.
4Reliability
If a thermoplastic mask is used to immobilize the patient's head, then the positioning reliability is improved, but the treatment cost increases
Solution Approach 1:
The force gauges can be removed from the straps after calibration and reused for subsequent patients or treatment sessions. Rather than discarding the entire mask system after one use, the reusable force gauge components can be recovered and applied to multiple patients, reducing the per-patient cost while maintaining positioning reliability through consistent force measurement and control.
Data Source
AI summary
An immobilization apparatus having at least one or more straps that engage a surface; wherein at least one of the straps comprises a force gauge to determine the amount of force applied to a patient immobilized with said straps; wherein the position of the patient is replicable for treatment of radiation and other head or neck treatments.