Handheld Spherical Antenna for Surgical Transponder Detection
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Solution Overview
Problem
Existing automated systems for detecting surgical objects using transponders are hindered by the high cost and variability in signal frequency of inexpensive transponders, leading to inaccurate detection in noisy environments, which can result in objects being mistakenly left in patients during surgery.
Innovation Solution
A hand-held transponder detection device with a spherically shaped coil form and three orthogonal antenna elements that emit wideband interrogation signals and filter return signals to determine the presence of resonant tag elements, using a processor to adjust signal detection thresholds based on noise levels and Q values for accurate detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If inexpensive transponders are used, then cost is reduced, but signal frequency variability increases making accurate detection difficult
Solution Approach 1:
The system dynamically adjusts the detection frequency range to match the actual resonant frequency of each transponder. The processor sweeps through a broad frequency spectrum (e.g., 100-200 kHz) to identify the peak response frequency of the transponder, then centers subsequent measurements on this dynamically determined frequency, allowing accurate detection despite transponder frequency variations
Solution Approach 2:
The system changes the detection parameter from a fixed frequency to a variable frequency that adapts to each transponder's resonant characteristics. By measuring Q-factor across multiple frequencies and identifying the peak response, the system determines the optimal detection frequency for each transponder instance, resolving the frequency variability issue
2Reliability
If a single detection system is installed in each surgery theater, then detection coverage is improved, but system cost increases
Solution Approach 1:
The detection system is designed as a universal platform that can serve multiple surgical theaters. The portable handheld detector can be moved between different operating rooms, and the system supports multiple transponder types and frequencies, making it adaptable to various surgical environments and reducing the need for dedicated systems in each theater
3Ease of manufacture
If transponders with large frequency variation are used, then transponder cost is reduced, but detection accuracy in noisy environments deteriorates
Solution Approach 1:
The system uses feedback from the transponder's actual response to adjust detection parameters. By measuring the Q-factor and identifying the peak frequency response, the system continuously adapts its detection frequency and threshold settings, enabling it to distinguish transponder signals from background noise even when transponders have large frequency variations
Solution Approach 2:
The system performs a preliminary frequency sweep to identify the transponder's resonant frequency before conducting the actual detection. This preliminary action characterizes the transponder's frequency response and sets optimal detection parameters, ensuring accurate detection in noisy environments before the surgical procedure begins
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
The device provides accurate and efficient detection of surgical objects, reducing the risk of leaving objects in patients and improving surgical safety by using inexpensive transponders effectively in noisy environments.
Implementation Method 1
a first antenna element which includes a first electrical wire wound around the outer coil support surface of a first one of the three coil support channels, the first antenna element arranged to transmit and receive signals
Implementation Method 2
resonant tag elements that produce return signals in response to energization
Data Source
AI summary
A hand-held antenna system allows medical personnel to ascertain the presence or absence of objects (e.g., medical supplies) tagged with transponders in an environment in which medical procedures are performed. In use, the hand-held antenna system may be positioned proximate a patient at a time after a medical procedure, such as after child birth, so the system can scan the patient's body to determine the presence of objects tagged with transponders. The antenna system includes three antenna elements arranged mutually orthogonal to each other to transmit and receive signals in three coordinate directions. A controller is coupled to the antenna elements to transmit signals to the transponders and to receive response signals. The antenna system may operate in a static scan mode wherein the antenna system is held in a fixed position by a user and a dynamic scan mode wherein the antenna system is moved by a user.