Direct comparison of biodistribution of [11C]DHTP and [11C]HTP in Sprague Dawley rats following radiotracer administration. Left panel: 30 min. Right panel: 60 min. Baseline uptake of [11C]DHTP in the endocrine pancreas had a tendency to increase compared to that of [11C]HTP. MAO inhibition had reduced effect on [11C]DHTP compared to [11C]HTP. Stars indicate level of significance (*p < 0.05; **p < 0.01; ***p < 0.001; ****p < 0.0001).