Which [18F]NaF PET Parameter is Most Effective for Assessing Treatment Response in Clinical Trials?

A research team assessed the response of various [18F]NaF PET markers (SUV, K1, k2, k3, k4, Fbv, k3/(k2+k3), Ki) to evaluate bone health after six months of treatment with teriparatide, a bone-building medication.

In another study, the same research team evaluated precision errors for these parameters as follows: SUV: ~11%, K1: ~36%, k2: ~52%, k3: ~28%, k4: ~33%, Fbv: ~55%, k3/(k2 + k3) = Ki/K1: ~19%, Ki: ~15%.

Researchers identified Ki and k3/(k2 + k3) as the most reliable markers for tracking treatment progress, with a high ratio of treatment response to precision error (greater than 1). This ratio is critical because if the treatment response is equal to or smaller than the precision error, the response is deemed ineffective.

These findings suggest that using Ki and k3/(k2 + k3) in clinical trials would require fewer participants (compared to other parameters) to achieve statistically meaningful results.

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Blake GM, Puri T, Siddique M, Frost ML, Moore AEB, Fogelman I. Site specific measurements of bone formation using [18F] sodium fluoride PET/CT. Quant Imaging Med Surg. 2018 Feb;8(1):47–59. doi: 10.21037/qims.2018.01.02. PMID: 29541623; PMCID: PMC5835654.