PT  - JOURNAL ARTICLE
AU  - Johannes Schwarz
AU  - Alexander Storch
AU  - Walter Koch
AU  - Oliver Pogarell
AU  - Perry E. Radau
AU  - Klaus Tatsch
TI  - Loss of Dopamine Transporter Binding in Parkinson’s Disease Follows a Single Exponential Rather Than Linear Decline
DP  - 2004 Oct 01
TA  - Journal of Nuclear Medicine
PG  - 1694--1697
VI  - 45
IP  - 10
4099  - http://jnm.snmjournals.org/content/45/10/1694.short
4100  - http://jnm.snmjournals.org/content/45/10/1694.full
SO  - J Nucl Med2004 Oct 01; 45
AB  - Imaging of l-dopa uptake or dopamine transporter binding can monitor the progression of Parkinson’s disease. Most follow-up studies have provided data best fitted by a linear decline of their outcome measure. However, in these studies, patients were repeatedly scanned during their first years after a diagnosis had been established. Methods: We followed 6 patients with early Parkinson’s disease for 7.5 y using 123I-labeled N-(3-iodopropene-2-yl)-2β-carbomethoxy-3β-(4-chlorophenyl) tropane and SPECT. Results: Loss of dopamine transporter binding was best fitted using a single exponential approximation. A 63% loss (τ [time constant tau]) was calculated as 5.18 ± 7.62 y in the putamen and 10.62 ± 31.4 y in the caudate nucleus when a 3-parameter fit was used. Conclusion: These data approximate, for what is to our knowledge the first time, the decline of dopamine transporter binding as expected in biologic systems and may allow for models that correct for exponential decline to be developed and for disease-modifying effects in patients with advanced disease to be determined.