SPECT Detector Module Calibration Using Imaging Examination Data
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Solution Overview
Problem
Current SPECT imaging systems require costly and hazardous uniform sources for calibration, which decay and need frequent replacement, and manual daily checks, causing delays and exposing technicians to radiation.
Innovation Solution
A computer-implemented method accumulates data from multiple imaging examinations to create energy and uniformity calibration maps without a uniform source, using pixel positions and isotopes to calibrate pixel energy and count uniformity, and identifies bad pixels for correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a uniform source is used for calibration, then calibration accuracy is improved, but system cost increases and the source requires frequent replacement due to radioactive decay
Solution Approach 1:
The patent extracts the calibration function from the uniform source itself and transfers it to the imaging data from multiple patients. Instead of relying on a physical radioactive source, the system uses statistical accumulation of imaging data to perform calibration, thereby eliminating the need for costly and decaying uniform sources while maintaining calibration accuracy
Solution Approach 2:
The patent makes the imaging data serve multiple functions: it performs both diagnostic imaging and calibration simultaneously. By accumulating data from multiple patient examinations, the system uses this multi-functional approach to derive calibration factors without requiring separate calibration procedures or additional radioactive sources
2Reliability
If manual daily calibration checks are performed, then calibration validity is ensured, but technician time is consumed and examination scheduling is delayed
Solution Approach 1:
The system performs self-calibration by automatically processing imaging data from multiple patients to generate calibration factors. This self-service mechanism eliminates the need for manual technician intervention in daily calibration checks, ensuring calibration validity while saving technician time and avoiding delays in examination scheduling
Solution Approach 2:
The patent performs calibration accumulation in the background during routine imaging examinations. By preliminarily accumulating data from multiple patients and computing calibration factors before they are needed, the system ensures calibration readiness without requiring time-consuming manual checks when patients are scheduled
3Measurement precision
If a uniform source is used for calibration, then calibration data is obtained, but technicians are exposed to ionizing radiation
Solution Approach 1:
The patent converts the harmful exposure to ionizing radiation into a benefit by using imaging data from actual patient examinations (which would be performed anyway for diagnostic purposes) to perform calibration. This approach eliminates additional radiation exposure to technicians while still obtaining the necessary calibration data from the same imaging process
4Reliability
If calibration procedures are performed, then calibration maps are updated, but the SPECT system cannot scan patients during calibration
Solution Approach 1:
The patent maintains continuous useful action by performing calibration accumulation in the background during routine patient imaging examinations. Instead of stopping scanning to perform calibration, the system continuously accumulates data from multiple patients and computes calibration factors without interrupting patient care, thereby maintaining both calibration accuracy and scanning productivity
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 approach reduces costs, eliminates the need for hazardous sources, and automates calibration, ensuring accurate imaging without manual checks, thus enhancing efficiency and safety.
Implementation Method 1
detects gamma rays emitted by a radiopharmaceutical administered to a patient
Implementation Method 2
a radiopharmaceutical administered to a patient in a region of interest of the patient over a plurality of angles
Data Source
AI summary
A method includes accumulating counts for each pixel in a set of pixels of one or more gamma cameras of a SPECT imaging system from a plurality of imaging examinations and each energy peak of each isotope used in the plurality of imaging examinations to produce an energy spectrum for each of the pixels at each of the energy peaks of each of the isotopes, determining, for the pixels and for the energy peaks, an energy calibration factor that converts an energy detected by each of the pixels to an energy of a corresponding energy peak and populating an energy map with the factors, and determining, for the pixels and for the energy peaks, a uniformity calibration factor that converts a number of counts detected by each of the pixels to a predetermined number of counts for a corresponding energy peak and populating a uniformity map with the factors.