PET Imaging of Monoamine Oxidase B in Peripheral Organs in Humans

PET Imaging of Monoamine Oxidase B in Peripheral Organs in Humans

Joanna S. Fowler, PhD¹, Jean Logan, PhD¹, Gene-Jack Wang, MD², Nora D. Volkow, MD², Wei Zhu, PhD³, Dinko Franceschi, MD², Naomi Pappas, MS², Richard Ferrieri, PhD¹, Colleen Shea, MS¹, Victor Garza, MS¹, Youwen Xu, MS¹, Robert R. MacGregor, BS¹, David Schlyer, PhD¹, S. John Gatley, PhD², Yu-Shin Ding, PhD¹ and David Alexoff, BS¹

¹ Chemistry Department, Brookhaven National Laboratory, Upton, New York
² Medical Department, Brookhaven National Laboratory, Upton, New York
³ Department of Applied Mathematics and Statistics, State University of New York Stony Brook, Stony Brook, New York

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FIGURE 1. Summed images (from 7 to 60 min) for 1 subject for ¹¹C-L-deprenyl (H) (top row) and ¹¹C-L-deprenyl-D2 (D) (bottom row). Planes from left to right show heart and lungs (planes 4 and 1); liver, stomach, and spleen (planes 17 and 14); and kidneys (planes 24 and 21). Note reduced accumulation of ¹¹C with ¹¹C-L-deprenyl-D2. Rainbow color scale is used.

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FIGURE 2. Time-activity curves for 1 subject for kidneys (A), heart (B), lungs (C), spleen (D), liver (E), and stomach (F) after injection of ¹¹C-L-deprenyl (H; •) and ¹¹C-L-deprenyl-D2 (D; ${circ}$ ). Note that maximum value of ordinate for heart, lungs, spleen, liver, and stomach is only half that of kidneys (0.02%/mL vs. 0.04%/mL).

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FIGURE 3. (A) Time-activity curves for arterial plasma for ¹¹C-L-deprenyl (H; •) and ¹¹C-L-deprenyl-D2 (D; ${circ}$ ). (B) Plasma integral for time-activity curves show that value of arterial plasma input function is greater with deuterium-substituted tracer.

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FIGURE 4. (A) Bar graph compares plasma-to-brain transfer function (K₁) for ¹¹C-L-deprenyl (H; ${blacksquare}$ ) and ¹¹C-L-deprenyl-D2 (D; ${square}$ ). (B) Bar graph compares ${lambda}$ k₃, which is index of MAO B activity. Note that values for K₁ did not differ except in kidney, which was barely significant (P < 0.04) in contrast to ${lambda}$ k₃_, which showed marked significant reductions in all organs (P < 0.003).

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FIGURE 5. Plot of ${partial}$ Ki/ ${partial}$ ${lambda}$ k₃( ${lambda}$ k₃/Ki) vs. ${lambda}$ k₃ for K₁ values of 0.25, 0.50, 1.0, 1.5, 2.0, and 2.5 mL/min/mL. Note that when Ki changes very little with relatively large changes in ${lambda}$ k₃, uptake is flow limited. With larger values of K₁, Ki is sensitive to changes in ${lambda}$ k₃ over much wider range than for lower values.