Optimization of self-reference thermometry using complex field estimation.

Area of Science:

• Medical Imaging
• Physics

Background:

• Referenceless thermometry, also known as self-reference thermometry, is crucial for mapping temperature variations.
• This technique relies on estimating a baseline phase from surrounding regions and subtracting it from the measured field.

Purpose of the Study:

• To propose and optimize a novel self-reference thermometry technique utilizing complex field estimation with 2D polynomials.
• To compare the performance of the complex-based method against a phase-based method.

Main Methods:

• A self-reference technique based on complex field estimation using 2D polynomials with complex-valued coefficients was developed and optimized.
• Numerical simulations, phantom experiments, and volunteer studies were conducted.
• The complex-based method was compared to a phase-based method, evaluating performance based on region of interest (ROI) radius and area ratios.

Main Results:

• Simulations indicated an ROI radius 2.3-2.5 times the standard deviation (SD) of the Gaussian function is needed to maintain <8% error.
• An area ratio between ROI and the region for estimation (RFE) greater than 2.0 is required to control error levels.
• The complex-based method showed utility when phase unwrapping was not performed; otherwise, the phase-based method achieved similar results with fewer polynomial orders.

Conclusions:

• The proposed complex-based referenceless thermometry method is a viable technique for temperature mapping.
• The choice between complex-based and phase-based methods depends on whether phase unwrapping is applied.
• Optimized polynomial orders are key for accurate temperature difference mapping in referenceless thermometry.