Areal Modulator for Proton Therapy Beam Segmentation
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Solution Overview
Problem
Current proton therapy systems face challenges in achieving both speed and accuracy in radiation treatment, with existing methods either being fast but less precise or accurate but slow, and both approaches risk uneven dose placement and patient movement issues.
Innovation Solution
A radiation therapy machine with an areal modulator that uses a radio-opaque plate with spaced channels to modulate an area beam, allowing for independent attenuation of radiation and precise control of Bragg peaks through fluid-filled cylinders and rotating shutters, enabling uniform exposure and rapid treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the proton beam is expanded to subtend the entire tumor with range spread (SOBP approach), then treatment speed is improved, but manufacturing precision and dose placement accuracy deteriorate
Solution Approach 1:
The proton beam is divided into multiple discrete pencil beams that are individually modulated in energy and intensity. Each pencil beam can be independently controlled to deposit dose at specific locations, allowing the tumor to be treated as a composite of smaller regions rather than a single expanded beam.
Solution Approach 2:
The system transitions from treating the entire tumor volume simultaneously with a single expanded beam to delivering dose through multiple discrete spatial points (pencil beams) that are distributed across the tumor volume. This adds a dimensional aspect of spatial discretization that enables both speed and precision.
2Manufacturing precision
If the proton beam is steered in angle and modulated in range to deposit dose as small spots (magnetic spot scanning), then dose placement accuracy is improved, but treatment speed deteriorates
Solution Approach 1:
The beam is segmented into multiple pencil beams that can be simultaneously positioned and modulated. Rather than moving a single beam through the tumor volume sequentially, multiple beams are distributed across the tumor and treated in parallel, dramatically increasing treatment speed while maintaining the precision of spot-based delivery.
Solution Approach 2:
The system uses spatial distribution of multiple pencil beams across the tumor volume, transforming the treatment from a single-point sequential process to a multi-point parallel process. This dimensional expansion in beam distribution enables simultaneous treatment of multiple tumor regions.
3Manufacturing precision
If small spot sizes are used in magnetic spot scanning, then dose placement accuracy is improved, but reliability deteriorates due to uneven dose placement and cold spots
Solution Approach 1:
Each pencil beam is independently modulated in energy and intensity to create locally optimized dose distributions. The energy modulation creates Bragg peaks at specific depths, and the intensity modulation controls the dose magnitude, allowing each small spot to deliver uniform dose while the collective arrangement covers the entire tumor volume uniformly.
Solution Approach 2:
The system maintains continuous dose delivery by overlapping adjacent pencil beam spots, ensuring that the transition between spots is seamless and creates a continuous, uniform dose distribution across the tumor volume without gaps or cold spots.
4Manufacturing precision
If patients are treated in many successive exposures, then dose placement accuracy is improved, but loss of time increases due to patient movement between exposures
Solution Approach 1:
The treatment is segmented into multiple pencil beams that are delivered simultaneously in a single exposure event. This parallel delivery approach reduces the number of separate exposure events from many sequential exposures to a single or few exposures, minimizing patient movement and time loss while maintaining the precision of spot-based dose delivery.
Solution Approach 2:
The system distributes multiple pencil beams across the tumor volume in a single exposure event, transforming the treatment process from many sequential time-based exposures to a single spatially-distributed exposure. This dimensional approach to beam distribution eliminates the time loss associated with repeated patient positioning.
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
This solution provides improved treatment speed and accuracy by allowing parallel modulation of the area beam, reducing cold spots, and enabling precise control of the Bragg peak, thus enhancing radiation therapy efficacy.
Implementation Method 1
a radio-opaque plate extending over an area of the area beam and having a plurality of channels within the area dispersed in two dimensions for passing radiation, the portion of the radio-opaque plate outside of the channels blocking passage of the radiation
Implementation Method 2
Each of the channels includes attenuation elements, located in the channels, to independently attenuate radiation passing through the channels
Implementation Method 3
rotating shutters, enabling uniform exposure and rapid treatment
Implementation Method 4
The dose deposited by a proton beam is not uniform along the entrance path of the beam, but rises substantially to a 'Bragg peak' near a point where the proton beam stops within the tissue
Data Source
AI summary
A modulator for radiation therapy provides modulation of an area beam to decrease treatment time. Separate channels passing modulated “beamlets” are possible by spacing the channels such that spreading of the beams and multiple angles of treatment eliminate cold spots. The space between the channels allows well-defined channel walls and space for modulator mechanisms.