Compact Gantry IMRT Machine for Head and Breast Treatments
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Solution Overview
Problem
Current Tomotherapy systems face limitations in precision and flexibility due to physical constraints, such as the width of modulated rays and accommodating patient body sizes and motion, particularly in treatments like breast tumors where out-of-plane gantry locations restrict dose placement and exposure.
Innovation Solution
A Tomotherapy machine with a shortened source to rotation axis distance, allowing for a compact gantry to be positioned around specific body parts, enabling narrower rays and improved resolution, specifically suited for head and breast treatments, with a beam modulator controlling radiation fluence and a stable rotating platform for precise dose placement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the source to rotation axis distance is shortened to create a compact gantry, then the gantry can be positioned around specific body parts (improving adaptability and reducing exposure to healthy tissues), but the physical space for shutter structure and beam modulation is reduced (worsening device complexity and manufacturing precision)
Solution Approach 1:
The patent transitions from a conventional linear arrangement of shutters along the beam path to a two-dimensional array of shutters positioned at an angle to the beam axis. This dimensional change allows the shutter array to fit within the constrained space of a compact gantry while still providing sufficient modulation capability for intensity-modulated radiation therapy.
Solution Approach 2:
The shutter array is positioned asymmetrically at an angle to the beam axis rather than perpendicular to it. This asymmetric configuration optimizes the use of available space in the compact gantry design while maintaining the ability to modulate beam intensity across the treatment field.
2Manufacturing precision
If the source to rotation axis distance is shortened, then narrower rays are naturally created (improving manufacturing precision and dose placement accuracy), but the gantry size is reduced (affecting ease of operation and patient positioning flexibility)
Solution Approach 1:
The patent employs a dynamic, computer-controlled shutter array that can independently modulate each beamlet in real-time. This dynamic control compensates for the reduced physical distance between source and rotation axis, maintaining precise dose placement accuracy while enabling the compact gantry design to be positioned flexibly around various patient anatomies.
3Ease of operation
If standard gantry locations are used for breast tumor treatment, then the gantry can be positioned in conventional locations (improving ease of operation), but out-of-plane locations restrict dose placement and expose healthy chest cavity tissues (worsening manufacturing precision and increasing harmful factors)
Solution Approach 1:
The patent applies local quality by using independent beamlet modulation within the shutter array to deliver different dose intensities to different regions of the treatment field. This allows precise targeting of the tumor while minimizing dose to surrounding healthy tissues, enabling the compact gantry to be positioned in optimized locations specific to each patient's anatomy rather than relying on standard positions.
Data Source
AI summary
A small field radiation therapy machine having an aperture diameter of 30 cm or less provides improved ray definition for specialized treatment of portions of the human body such as head a breast.