SPECT/CT imaging: quantifying ^99mTc-MDP concentration in the spine and pelvis

Area of Science:

• Nuclear Medicine
• Radiopharmacology
• Oncologic Imaging

Background:

• Standardized uptake values (SUVs) in bone SPECT/CT imaging require robust normalization for accurate clinical interpretation.
• Various normalization methods exist, including those based on body weight, lean body mass, bone mineral content, body surface area, and body mass index.

Purpose of the Study:

• To quantitatively measure and compare different SUV normalization methods for 99mTc-MDP in normal spine and pelvis.
• To identify a robust SUV normalization method for guiding clinical practice in oncology.

Main Methods:

• Retrospective analysis of 500 oncology patients undergoing 99mTc-MDP bone SPECT/CT.
• Calculation of mean SUVs (SUVmean) using body weight (SUVbw), lean body mass (SUVlbm), bone mineral content (SUVbmc), body surface area (SUVbsa), and body mass index (SUVbmi).
• Comparison of coefficients of variation (CoVs) and correlation/regression analyses with patient factors (sex, age, height, weight, BMI, CT values).

Main Results:

• SUVbsa demonstrated the lowest coefficient of variation (42.1%) across all analyzed vertebrae and pelvis.
• SUVbsa showed weaker correlations with age and CT values compared to other SUVs.
• Regression analysis indicated SUVbsa was independently influenced by age, BMI, and CT values, with smaller effects than conventional SUVbw.

Conclusions:

• Quantitative bone SPECT/CT SUVs of 99mTc-MDP in normal bone can guide tumor bone metastasis evaluation, requiring site-specific assessment.
• SUV normalized by body surface area (SUVbsa) offers superior robustness among tested normalization methods.
• SUVbsa holds potential for broader clinical applications in oncologic imaging.