Dual-axis ring gantry for non-coplanar radiotherapy

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Solution Overview

Problem

Current radiation systems face limitations in providing non-coplanar treatment capabilities, rapid cone beam computed tomography (CBCT), simplified collision avoidance, and whole-body treatments, with C-arm systems struggling with collision avoidance and CBCT times, and ring gantry systems lacking non-coplanar treatment options.

Innovation Solution

A radiation system that employs two axes of rotation, combining the strengths of C-arm and ring gantry systems, allowing for a wide range of coplanar and non-coplanar beam angles by using a first gantry rotating about the superior-inferior axis and a second gantry rotating about a circular orbit, with paired stereo kV sources and a mega-voltage electronic portal imaging device for enhanced imaging and treatment planning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a C-arm gantry is used, then non-coplanar treatment capabilities are provided, but collision avoidance becomes complicated and CBCT scan times increase

Engineering Contradiction:
Improvenon-coplanar treatment capabilitiesVSAvoidcollision avoidance complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent transitions from a single-axis C-arm gantry to a dual-axis ring gantry system. The first gantry rotates about a first axis (azimuthal rotation) and the second gantry rotates about a second axis (elevation rotation), adding a dimensional degree of freedom. This dual-axis configuration enables non-coplanar treatment angles while the ring geometry provides inherent collision avoidance by allowing the radiation source to access the patient from multiple angular dimensions without interfering with the treatment table or room structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If a C-arm gantry is used, then non-coplanar treatment capabilities are provided, but CBCT scan times become long

Engineering Contradiction:
Improvenon-coplanar treatment capabilitiesVSAvoidCBCT scan time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The ring gantry system enables continuous, rapid rotation about both axes during CBCT acquisition. The dual-axis configuration allows the radiation source to continuously sweep through the required angular range without mechanical interruptions or repositioning, significantly reducing scan time compared to sequential single-axis C-arm systems that require stopping and repositioning between angular segments.

Inventive Principle:
Principle #20Continuity of useful action

3Productivity

If a ring gantry is used, then rapid CBCT acquisitions and simplified collision avoidance are achieved, but non-coplanar treatment capabilities are lost

Engineering Contradiction:
ImproveCBCT acquisition speedVSAvoidnon-coplanar treatment capabilities
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The system employs two independently controllable gantries with rotational degrees of freedom. The first gantry provides azimuthal rotation and the second gantry provides elevation rotation, creating a dynamic positioning system that can rapidly acquire CBCT data by rotating through standard angles while simultaneously providing non-coplanar treatment capabilities by adjusting both angular dimensions. This dynamic dual-axis configuration resolves the contradiction between speed and versatility.

Inventive Principle:
Principle #15Dynamics

4Device complexity

If a single-axis gantry is used, then device complexity is reduced, but treatment flexibility and beam angle range are limited

Engineering Contradiction:
Improvegantry structure simplicityVSAvoidbeam angle range
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The gantry system is segmented into two independent rotational components: the first gantry providing rotation about a first axis and the second gantry providing rotation about a second axis. This segmentation allows each component to be relatively simple in structure while their combined operation produces complex, flexible beam positioning capabilities. The modular dual-gantry design achieves treatment flexibility without requiring a single overly complex mechanical structure.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3612273B1Dual-axis ring gantry radiotherapy systems
Publication Date: 2022.03.16 VARIAN MEDICAL SYSTEMS INC
  • EP3612273B1 patent drawingFigure 1A~1B
  • EP3612273B1 patent drawingFigure 2A~2B
  • EP3612273B1 patent drawingFigure 2C~2D

AI summary

A radiation system includes a radiation source providing therapeutic radiation, a first gantry supporting a second gantry carrying the radiation source. The first gantry is rotatable about a first axis passing through an isocenter, thereby allowing the radiation source to aim therapeutic radiation at a target volume from a plurality of locations in a first plane. The second gantry carrying the radiation source is rotatable about a second axis passing through the isocenter non-parallel with the first axis, thereby allowing the radiation source to aim therapeutic radiation at the target volume from a plurality of locations in a second plane non-coplanar with the first plane.