SiPM-Based Multispectral Optical Probe for Real-Time Radiotherapy Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current radiotherapy methods rely on offline evaluations and expose both cancerous and non-cancerous tissues to high levels of ionizing radiation, leading to inefficient tumor treatment and increased radiation-induced side effects due to inaccuracies in patient placement and internal organ motion.
Innovation Solution
A multispectral optical probe using silicon photomultiplier (SiPM) detectors to detect Cerenkov emission during radiation therapy, allowing for real-time monitoring and adjustment of radiation beams to improve targeting accuracy and reduce side effects by differentiating between cancerous and normal tissues based on spectral analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If offline evaluation methods with added margins are used for radiation treatment planning, then setup adjustments can be made based on CBCT, but both cancerous and non-cancerous tissues are exposed to high levels of ionizing radiation, resulting in inefficient tumor cell kill and increased radiation-induced side effects
Solution Approach 1:
The patent applies preliminary action by implementing real-time dosimetry monitoring during radiation delivery to detect and correct placement inaccuracies and organ motion immediately, rather than relying on offline CBCT evaluations made just prior to treatment. This continuous monitoring enables timely adjustments that prevent both cancerous and non-cancerous tissues from being unnecessarily exposed to high radiation levels, thereby improving targeting accuracy while reducing radiation-induced side effects
2Measurement precision
If real-time dosimetry monitoring is implemented to improve targeting accuracy, then radiation delivery precision can be enhanced, but the complexity of the treatment system increases
Solution Approach 1:
The patent employs an intermediary approach by introducing a dedicated real-time dosimetry monitoring system with detectors positioned to measure radiation dose distribution during delivery. This intermediary monitoring layer provides critical feedback information without fundamentally altering the primary radiation treatment delivery system, thereby enabling enhanced precision while managing complexity through modular integration rather than system-wide redesign
3Measurement precision
If conventional photodetectors are used to detect Cerenkov emission, then radiation measurement can be performed, but the sensitivity is insufficient for accurate in vivo dosimetry
Solution Approach 1:
The patent applies parameter changes by transitioning from conventional photodetectors to silicon photomultiplier (SiPM) detectors, which represent a significant change in detector technology parameters. SiPM detectors offer substantially higher sensitivity and detection efficiency for Cerenkov emission in the blue spectrum, enabling accurate in vivo dosimetry measurements that were not achievable with conventional photodetectors, thereby simultaneously improving both measurement precision and detection reliability
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 SiPM-based optical probe enhances the precision of radiation delivery by providing real-time physiological information, enabling more accurate tumor targeting and reduced exposure to healthy tissues, thus improving treatment efficacy and minimizing side effects.
Implementation Method 1
a first optical bandpass filter that operates to pass Cerenkov radiation (CE) in a first range of wavelengths; a first silicon photomultiplier (SiPM) photodetector configured to receive radiation passed through the first optical bandpass filter and, in response thereto, generate a first optical response signal
Implementation Method 2
a first optical bandpass filter that operates to pass Cerenkov radiation (CE) in a first range of wavelengths; a second optical bandpass filter arranged adjacent to the first optical bandpass filter and operates to pass Cerenkov radiation in a second range of wavelengths
Implementation Method 3
a first silicon photomultiplier (SiPM) photodetector configured to receive radiation passed through the first optical bandpass filter and, in response thereto, generate a first optical response signal
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Cerenkov Emission (CE) during external beam radiation therapy (EBRT) from a linear accelerator (Linac) has been demonstrated as a useful tool for radiotherapy quality assurance and potentially other applications for online tracking of tumors during treatment. However, an overlooked area is the molecular probing of the cancer status during delivery mainly due to the limited detection sensitivity of CE and lack of flexible tools to fit into an already complex treatment delivery environment. Silicon photomultiplier (SiPM) can be used for low light detection due to their extreme sensitivity that mirrors photomultiplier tubes and yet has a form factor that is similar to silicon photodiodes, allowing for improved flexibility in device design. This work assesses the feasibility of using SiPMs to detect CE, interrogate the tumor molecular status during EBRT, and contrast its performance with silicon photodiodes (PDs) available commercially.