Surface Camera Alignment for CT-Less Free-Breathing Contours
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Solution Overview
Problem
Current radiation treatment systems require two CT scans to capture deep inspiration breath-hold (DIBH) and free breathing (FB) contours, which is inefficient and increases ionizing radiation exposure, especially as many hospitals now only perform CT scans in DIBH.
Innovation Solution
A method using a surface camera and tomography to capture FB contours, transforming them into a coordinate system aligned with DIBH contours, eliminating the need for additional ionizing radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a CT scan is performed to acquire the free breathing contour, then the contour data is obtained, but the patient is exposed to additional ionizing radiation
Solution Approach 1:
The patent replaces the CT scanning system (ionizing radiation-based) with a surface camera system (optical/non-ionizing) for acquiring free breathing contour data. The camera captures optical images of the patient's body surface, which are then processed to generate the required contour data, thereby eliminating additional radiation exposure while maintaining measurement capability.
Solution Approach 2:
The patent creates a optical copy (photograph) of the patient's body surface using a camera instead of creating an ionizing radiation copy via CT scan. This optical copy contains sufficient surface contour information that can be processed to match the required precision for treatment planning, avoiding the harmful effects of repeated CT radiation exposure.
2Object-affected harmful factors
If only a DIBH CT scan is performed, then radiation exposure is reduced, but the free breathing contour cannot be obtained
Solution Approach 1:
The patent introduces a surface camera as an intermediary device that captures body surface information during free breathing. This intermediary optical recording system bridges the gap between the single DIBH CT scan and the need for free breathing contour data, allowing the contour information to be extracted from optical images without requiring a separate CT scan.
Solution Approach 2:
The patent substitutes the CT scanning mechanism with an optical camera system for capturing free breathing state information. The camera records the body surface geometry during free breathing, and this optical data is then processed to generate the contour, replacing the need for ionizing radiation-based imaging in the free breathing state.
3Measurement precision
If two CT scans are performed for DIBH and free breathing contours, then both contours are available, but the treatment planning time and radiation exposure increase
Solution Approach 1:
The patent merges the functions of two separate CT scans into a single hybrid workflow: one CT scan for DIBH internal anatomy and one camera capture for free breathing surface contour. This combination reduces the total number of imaging procedures while maintaining the ability to align both contours through coordinate system transformation, thereby reducing both time and radiation exposure.
Solution Approach 2:
The patent makes the camera system multi-functional by using it to capture both the free breathing contour and providing reference points for coordinate transformation. This single device performs multiple functions (contour capture, positioning reference, alignment facilitation) that would otherwise require separate imaging procedures, streamlining the overall process.
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
Enables accurate alignment of FB and DIBH contours without additional ionizing radiation, facilitating precise radiation treatment planning.
Implementation Method 1
taking images of a surface of an anatomical body part during both free breathing and deep inspiration breath-hold using a surface camera
Implementation Method 2
a tomography such as a CT of the anatomical body part during deep inspiration breath-hold
Data Source
AI summary
Disclosed is a method of transforming a first medical image dataset describing an anatomical body part of a patient into a reference system of a second medical image dataset describing the anatomical body part. The method encompasses taking images of a surface of an anatomical body part during both free breathing and deep inspiration breath-hold using a surface camera as well as a tomography such as a CT of the anatomical body part during deep inspiration breath-hold. Contours are extracted from the surface camera images and the tomography representing a contour of the anatomical body part such as a surface of the patient's thorax. The contour extracted from the camera image taken during free breathing is transformed into a coordinate system used for defining positions in the tomograph (i.e. a coordinate system used by the tomograph used for generating the tomography) by fusing the contour extracted from the tomography with the contour extracted from the deep inspiration breath-hold camera image and applying the transformation representing the fusion result to the camera image taken during free breathing.