タイトル無し
スポンサーリンク
概要
- 論文の詳細を見る
The output (observations) of the tracer kinetic process is usually expressed by a sum of decaying exponemtials : <I>q</I> (<I>t</I>) =<I>p</I>Σ<I>i</I>=1 <I>A<SUB>i</SUB></I> exp (-α<I><SUB>i</SUB>t</I>). The compartmental analysis which is widely used in the tracer kinetic study is a method by which the pertinent parameters (<I>A<SUB>i</SUB></I> and α<I><SUB>i</SUB></I>) as well as number of compartments (<I>p</I>) are determined. In this study the optimal time scale interval (τ) and sample size (<I>m</I>) in a definite set of observations in radio-isotope (RI) tracer kinetics were obtained to minimize the variances of the parameters (<I>A<SUB>i</SUB></I> and α<I><SUB>i</SUB></I>), assuming the observations to be Poisson-distributed. The best unbiased estimators of variances of the parameters were obtained by the Fisher in formation and the Cramér-Rao inequality. Since the expectation value in the <I>j</I>th observation <<I>nj</I>> is represented by <<I>nj</I>> =∫<I>tj</I><I>tj</I>-1 <I>p</I>Σ<I>i</I>=1 <I>A<SUB>i</SUB></I> exp (-α<I><SUB>i</SUB>t</I>) <I>dt</I> in RI study, the information matrix can be defined by <I>A<SUB>i</SUB></I>, α<I><SUB>i</SUB></I>, τ and <I>m</I>.<BR>Analysis of the effect of the sample size (<I>m</I>), the time scale interval (τ) and the number of exponentials (<I>p</I>) on the variance of <I>A<SUB>i</SUB></I> and α<I><SUB>i</SUB></I> by numerical examples revealed the following results : (1) For a fixed sample size, there is an optimal time scale interval which increases with sample size. (2) For a fixed time scale interval, the variance of each parameter decreases withthe sample size, but it converges to a certain level for a large sample size. (3) The allowable limit on τ as the optimal time scale interval decreases with increase of the number of exponentials.<BR>Application of this method to the dynamic study of cerebral circulation using <SUP>133</SUP>Xe revealed that 15-20 minutes of sampling period was necessary to estimate the pertinent parameters accurately.
- 一般社団法人 日本生体医工学会の論文
一般社団法人 日本生体医工学会 | 論文
- Evaluating the Workload Reduction of Automatic Vital Data Transmission
- Mental Fatigue Measurement Based on the Changes in Flicker Perception Threshold using Consumer Mobile Devices
- A Theoretical Study on a Computational Algorithm for Human Posture Estimation Based on Motion Capture of a Small Number of Markers
- Latest microscopic technique. From the principle to application. Development of three-dimensional microscopic system for operation of mini-pig fertilized eggs.
- A Study of the Automation of Cytodiagnosis (The Second Report):Cytophotometry Using Photomicroscanner and a Trial of Data-processing