Omission of serial arterial blood sampling for quantitative analysis of monkey PET data using independent component analysis-based method

Serial arterial blood sampling is required to measure a blood input function in quantitative estimation of physiological parameters in dynamic positron emission tomography (PET) studies. However, blood sampling is problematic for animal PET study due to limited amount of blood allowed. Therefore, it is of interest to obviate arterial blood sampling. We have previously proposed a method for estimating a blood input curve based on independent component analysis in human study. In this paper, we applied the method to monkey [¹⁸F]fluorodeoxyglucose studies, and validated its applicability by comparing the estimated regional cerebral metabolic rates of glucose using the estimated and the measured blood input function. Experimental results suggest that the proposed method enables quantitative analysis in PET without serial arterial blood sampling not only in human data but also in monkey data.

I. Introduction

Quantitative analysis in positron emission tomography (PET) is based on a relationship between a time-activity curve of an administered tracer (plasma time-activity curve; pTAC) and a time-activity curve in the target tissue (tissue time-activity curve, tTAC). For example, the following equation describes the relationship in [¹⁸F]fluorodeoxyglucose ([¹⁸F]FDG), which is a glucose analog and measures regional cerebral glucose metabolism [1].

$$C_{{\rm t}}(t)={k_1\over k_{2}+k_{3}}\left\{k_{3}+k_{2}\exp(-(k_{2}+k_{3})t)\right\}\otimes C_{{\rm p}}(t),\eqno{\hbox{(1)}}$$ where and are the tTAC and pTAC, respectively, and ⊗ is a convolution operation. to are kinetic parameters that describe the behavior of [¹⁸F]FDG. Especially, a combined parameter, , which is proportional to regional cerebral metabolite rate of glucose, is estimated as a slope using the Patlak Plot [2]. $${C_{{\rm t}}(t)\over C_{{\rm p}}(t)}=K_{i}{\int\nolimits_{0}^{t} C_{{\rm p}}(u){\rm d}u\over C_{{\rm p}}(t)}+V,\eqno{\hbox{(2)}}$$ where is a constant intercept.