Comparison Between Prone SPECT-Based Semi-Quantitative Parameters and MBI-Based Semi-Quantitative Parameters in...

Area of Science:

• Nuclear Medicine
• Oncology
• Radiology

Background:

• Locally advanced breast cancer (LABC) requires accurate methods for treatment response assessment.
• Molecular Breast Imaging (MBI) and single-photon emission computed tomography (SPECT) are functional imaging techniques used in breast cancer diagnostics.
• Semi-quantitative parameters derived from these imaging modalities may offer insights into treatment efficacy.

Purpose of the Study:

• To evaluate semi-quantitative SPECT parameters from prone SPECT using [99mTc]Tc-sestamibi.
• To compare these SPECT-derived parameters with MBI-derived semi-quantitative parameters.
• To assess the potential of these parameters for predicting treatment response in LABC patients.

Main Methods:

• Prospective enrollment of LABC patients with tumors ≥2 cm.
• Performance of early (5 min) and delayed (90 min) prone SPECT/CT scans after [99mTc]Tc-sestamibi injection.
• Calculation of wash-out rates (WOR) and other semi-quantitative parameters including functional tumor volume (FTV), standardized uptake values (SUVmax, SUVmean), and tumor-to-background ratios (TBR).
• Comparison of SPECT-derived FTV, TBR, and coefficient of variation (COV) with corresponding MBI-derived parameters.

Main Results:

• Feasibility of obtaining semi-quantitative parameters from prone SPECT/CT in LABC patients.
• Early SUVmax and TBRmax showed significantly higher interquartile ranges than SUVmean and TBRmean.
• Functional tumor volume (FTV) derived from early prone SPECT/CT was comparable to MBI-derived FTV (p=0.46).
• Significant variation in wash-out rates (WOR) was observed among patients.

Conclusions:

• Semi-quantitative analysis of prone SPECT/CT is feasible in LABC patients.
• Early prone SPECT/CT-derived FTV shows comparability with MBI-derived FTV.
• Further studies incorporating comprehensive clinical parameters are necessary to establish the clinical relevance of these semi-quantitative parameters, including WOR, for response prediction in routine clinical practice.