Phased Array Tumor Marker Localization With Adaptive Impedance Matching
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Solution Overview
Problem
Current systems for real-time tumor positioning in radiation therapy face challenges such as limited field of view, high electromagnetic radiation exposure to patients, and inefficiencies due to antenna impedance mismatch, particularly for patients with large body sizes and during radiotherapy.
Innovation Solution
A phased array antenna system with a processor that transmits and receives wireless signals to implanted markers, using adaptive impedance matching and a ferromagnetic layer to reduce EM radiation exposure and improve tracking accuracy, while allowing for precise localization of tumors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a wireless transceiver is placed on top of the patient to track tumor location, then millimeter range accuracy is achieved, but the system blocks the beam path during radiotherapy and exposes the patient to significantly high EM radiation
Solution Approach 1:
The patent extracts the tracking function from an active transceiver system and implements it using a passive RFID tag system. The passive tag is implanted near the tumor and can be tracked by external readers without requiring an active transmitter in the patient's body, thereby eliminating the blocking issue and reducing EM radiation exposure while maintaining millimeter-level tracking accuracy
Solution Approach 2:
The patent introduces a ferromagnetic layer as an intermediary component between the antenna and the patient's body. This layer focuses and directs the EM field toward the implant site, improving coupling efficiency with the passive RFID tag while reducing the overall EM radiation dose required for tracking, thus addressing both the accuracy and radiation exposure concerns
2Measurement precision
If a wireless transceiver is placed on top of the patient to track tumor location, then millimeter range accuracy is achieved, but navigation volume is limited by the generated magnetic field and usage is limited for patients with large body size
Solution Approach 1:
By extracting the active transmission function from the implanted device and placing it in external readers, the system eliminates the magnetic field generation limitation. The passive RFID tags can be tracked over larger volumes and distances without the constraints of a limited onboard power source and magnetic field range, making the system suitable for patients with large body sizes
Solution Approach 2:
The patent uses multiple external antenna elements that can be selectively activated to create virtual antenna positions. This allows the system to electronically steer and expand the navigation volume without physically moving or reconfiguring the implanted passive tag, enabling tracking across larger patient anatomies while maintaining millimeter-level accuracy
3Measurement precision
If a wireless transceiver is placed on top of the patient to track tumor location, then tumor positioning is achieved, but lots of EM energy is wasted due to antenna impedance mismatch
Solution Approach 1:
The ferromagnetic layer acts as an intermediary that focuses and directs the EM field energy toward the implant site. This improves the coupling efficiency between the external antenna and the passive RFID tag, reducing energy loss due to impedance mismatch and minimizing wasted EM energy while maintaining effective tracking capability
Solution Approach 2:
The patent employs adjustable impedance matching circuits and reconfigurable antenna elements that can adapt their electrical parameters to optimize coupling with the passive RFID tag. By dynamically adjusting impedance parameters, the system minimizes energy loss due to mismatch while maintaining accurate tumor localization capability
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 system effectively reduces EM radiation exposure and improves tracking accuracy for tumor localization, accommodating larger patients and minimizing beam path interference during radiotherapy.
Implementation Method 1
the processor is configured to determine a location of the wireless marker based on a time of flight of the transmitted and received wireless signals
Implementation Method 2
a ferromagnetic layer to reduce EM radiation exposure and improve tracking accuracy
Data Source
AI summary
The present disclosure provides an apparatus for determining a location of a wireless marker for a tumor, the apparatus comprising: a phased array antenna, and a processor, wherein the processor is configured to control the phased array antenna to transmit a wireless signal to the wireless marker, receive a wireless signal transmitted by the wireless marker in response to the transmitted wireless signal, and analyze the wireless signals transmitted and received by the phased array antenna to determine a location of the wireless marker. The present disclosure also provides a method for determining a location of a wireless marker for a tumor, wherein the method comprises: transmitting, using a phased antenna array, a wireless signal to the wireless marker, receiving, at the phased antenna array, a wireless signal transmitted by the wireless marker in response to the transmitted wireless signal, and analyzing the wireless signals transmitted and received by the phased array antenna to determine a location of the wireless marker.