MR-Guided Charged Particle Beam Steering to Reduce Lorentz Deflection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current MR-guided radiotherapy systems face challenges in accurately locating tumor target spots due to deflected charged particle beams caused by the Lorentz force from the main magnetic field of MR, leading to inaccurate irradiation and increased lateral scattering, which complicates treatment precision and normal tissue protection.
Innovation Solution
An MR-guided charged particle beam radiotherapy device with a multi-stage EM steering coil set and MR imaging device, generating charged particle beams parallel to the main magnetic field, and an EM steering parameter commissioning method to optimize beam direction and confinement, using a Bayesian black-box optimization algorithm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If charged particle beams are used for radiotherapy in MR-guided system, then treatment precision and soft tissue discrimination are improved, but beam deflection due to Lorentz force causes difficulty in accurate tumor targeting
Solution Approach 1:
The patent converts the harmful Lorentz force effect into a beneficial tool by using electromagnetic steering coils to intentionally deflect the charged particle beam. The system uses the same magnetic field interaction that causes unwanted deflection to enable precise beam steering and positioning, transforming the problem into a solution mechanism.
Solution Approach 2:
The patent introduces electromagnetic steering coils as an intermediary device between the charged particle beam source and the tumor target. These coils generate controlled magnetic fields that mediate the beam's path, allowing precise positioning while compensating for the inherent Lorentz force deflection in the main MR magnetic field.
2Measurement precision
If main magnetic field shielding is added to reduce beam deflection, then beam accuracy is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the beam steering function from the main magnetic field shielding structure and implements it through separate electromagnetic steering coils. This separates the MR imaging magnetic field function from the beam positioning function, avoiding the need for complex shielding modifications while maintaining beam accuracy.
Solution Approach 2:
The electromagnetic steering coils serve multiple functions: they steer the charged particle beam to the target, compensate for Lorentz force deflection, and enable dynamic beam positioning. This multi-functional approach replaces what would otherwise require complex dedicated shielding structures.
3Measurement precision
If charged particle beams are transported through MR magnetic field, then MR imaging guidance is achieved, but lateral scattering increases and normal tissue protection deteriorates
Solution Approach 1:
The patent applies preliminary electromagnetic steering to confine and focus the charged particle beam before it enters the patient's body. By pre-positioning and narrowing the beam trajectory using electromagnetic fields, the system reduces lateral scattering during tissue traversal and improves normal tissue protection.
Solution Approach 2:
The patent dynamically adjusts electromagnetic field parameters (strength, direction, distribution) to optimize beam confinement throughout its path. By changing these parameters in real-time based on MR imaging feedback, the system maintains tight beam confinement to minimize lateral scattering while preserving MR imaging guidance capabilities.
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 and method improve treatment precision by reducing beam deflection and lateral scattering, ensuring accurate tumor targeting and better protection of normal tissues.
Implementation Method 1
a charged particle beam transported in a main magnetic field of MR is affected by the Lorentz force
Implementation Method 2
a charged particle beam EM steering device, including a multi-stage EM steering coil set
Data Source
AI summary
The present disclosure provides a magnetic resonance (MR)-guided charged particle beam radiotherapy device, and an electromagnetic (EM) steering parameter commissioning method aiming at target spots. The device of the present disclosure includes: a charged particle beam EM steering device, a charged particle beam sequentially passing through a multi-stage EM steering coil set to generate a parallel charged particle beam in the same direction as a main magnetic field of MR, and an MR imaging device, including an upper and a lower group of main magnetic field coils. According to the present disclosure, the charged particle beams parallel to the main magnetic field of MR and aiming at preset targets spots can be generated, which greatly reduces the effect of the Lorentz force on the charged particle beams and enhance their dosimetric advantages, thereby improving dose delivery accuracy of the charged particle beams to target spots under MR guidance.