Radiation Dose Measurement via Inverse Attenuation
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Solution Overview
Problem
Current radiation therapy systems face challenges in accurately measuring the actual dose delivered to patients due to factors like penumbra regions around treatment field edges, which can differ from planned doses, necessitating improved dosimetry methods.
Innovation Solution
A system and method that include obtaining treatment plans and images, determining primary and inversely-attenuated images, and estimating machine parameters using a penumbra model and forward dose calculation algorithms to accurately measure the dose delivered.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional radiation therapy dosimetry methods are used, then the measurement process is simple, but the measurement precision is insufficient due to penumbra region effects
Solution Approach 1:
The patent segments the radiation field into primary regions and penumbra regions, applying different analysis methods to each. The primary images are separated from treatment images, and penumbra models are applied specifically to edge regions, allowing precise dose measurement without requiring complete system redesign.
Solution Approach 2:
The patent performs preliminary actions by obtaining treatment plans and planning images before actual treatment, and by pre-establishing penumbra models based on collimator characteristics. This preparatory work enables accurate dose estimation during treatment without adding complexity to the real-time measurement process.
2Measurement precision
If penumbra models and forward transport simulations are used, then the dose estimation accuracy is improved, but the computational time increases
Solution Approach 1:
Penumbra models and transport parameters are calculated in advance during treatment planning, before actual treatment delivery. This preliminary computation stores penumbra characteristics that can be quickly applied during treatment without requiring real-time complex simulations, thus improving accuracy while minimizing computational time loss.
Solution Approach 2:
The patent applies full forward transport simulations and penumbra modeling only where necessary - specifically in penumbra regions and for primary image determination - rather than throughout the entire treatment field. This partial application maintains accuracy where needed while reducing overall computational burden.
3Measurement precision
If inverse attenuation to the collimator plane is performed, then the machine parameter estimation accuracy is improved, but the processing complexity increases
Solution Approach 1:
The patent introduces an intermediate processing step of inverse attenuation that transforms treatment images to the collimator plane. This intermediary transformation serves as a bridge between raw treatment images and machine parameter estimation, improving accuracy by accounting for attenuation effects while maintaining a systematic and manageable processing workflow.
Data Source
AI summary
The present disclosure provides a system and method for medical imaging. The method may include obtaining a treatment plan, a planning image, and one or more treatment images of the subject, wherein the one or more treatment images are generated by performing at least a portion of the treatment plan including delivering at least a radiation beam towards the subject using a radiation device. The method also includes determining primary images of the subject based on the one or more treatment images, and determining inversely-attenuated primary images of the subject by inversely attenuating the primary images to a plane located between the subject and a collimator assembly of the radiation device. The method may further include estimating machine parameters of the radiation device corresponding to the inversely-attenuated primary images.