XACT In Vivo Dosimetry With Absolute 3D Dose Reconstruction
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Solution Overview
Problem
Current radiation therapy dosimetry methods lack a 3D in-vivo device capable of accurately measuring the delivered dose to patients, particularly during high-dose delivery treatments like FLASH radiotherapy and SBRT, limiting the precision of adaptive radiotherapy.
Innovation Solution
Developed a model-based reconstruction algorithm for X-ray-induced acoustic computed tomography (XACT) to deconvolute the effects of X-ray pulse shape and ultrasound detector frequency response, enabling 3D real-time absolute in-tumor dosimetry.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional dosimetry tools (TLDs, film dosimetry, EPID) are used, then dose measurement is possible, but 3D real-time absolute dose reconstruction capability is lacking
Solution Approach 1:
The patent combines X-ray imaging capability with acoustic detection to create an integrated system that performs both anatomical imaging and dose measurement simultaneously, enabling 3D real-time absolute dose reconstruction without requiring separate measurement devices
Solution Approach 2:
The patent introduces acoustic waves as an intermediary medium that carries dose information from the treatment region to external detectors, allowing non-invasive 3D dose measurement through the patient's body without direct sensor placement in the tumor
2Measurement precision
If XACT imaging is used for relative dosimetry, then 3D dose distribution can be visualized, but absolute dose reconstruction is not achievable due to pulse duration and frequency response effects
Solution Approach 1:
The patent performs preliminary characterization of the X-ray pulse shape and detector frequency response before the actual dosimetry measurement, storing these parameters for later use in deconvolution to enable accurate absolute dose reconstruction
Solution Approach 2:
The patent replaces direct mechanical measurement with signal processing-based deconvolution, using computational methods to separate the effects of pulse duration and frequency response from the measured acoustic signal, thereby achieving absolute dose measurement without physical modification of the measurement system
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 XACT imaging system provides accurate, absolute dose reconstruction, validated by simulation and experimental data, facilitating precise monitoring of radiation delivery and potential clinical application.
Implementation Method 1
a pulsed x-ray excites a target and results in rapid localized heating
Implementation Method 2
rapid localized heating leads to the generation of acoustic waves
Implementation Method 3
immersion ultrasound transducer
Data Source
AI summary
The present embodiments relate generally to increasing the precision of radiotherapy by measuring the absolute dose delivered to the tumor and surrounding normal tissue during the treatment. More particularly, some embodiments relate to an imaging reconstruction system for X-ray-induced acoustic computed tomography (XACT) using a model-based reconstruction method. Instead of reconstructing relative dose information for radiation beam localization, the system is capable of reconstructing absolute in vivo dose information. The XACT absolute in vivo dosimetry tool holds great potential for personalized cancer treatment and better outcomes. In some embodiments, thermal parameters, such as Gruneisen parameters, are used to convert reconstructed pressure information to dose. In addition, to avoid problems caused by electrical system gain, calibration tools, such as ion chambers, can be used to calibrate the system.