Additional file 1: Figure S1. of A novel 11C-labeled thymidine analog, [11C]AZT, for tumor imaging by positron emission tomography

PET images of C6 and HeLa tumor-bearing mice between 30 and 60 min after injection of 50 MBq of [11C]AZT (A) and [11C]d4T (B). Arrows and arrowheads indicate the C6 and HeLa tumors, respectively. Figure S2 [11C]AZT and [18F]FDG uptake in aseptic inflammation model mice. Representative coronal PET images for [11C]AZT (A) and [18F]FDG (B) between 60–80 min after injection. Yellow dot circles indicated turpentine oil-induced inflammatory tissue. Biodistribution of [11C]AZT (C) and [18F]FDG (D) in turpentine oil-treated (black bar) and untreated (white bar) posterior thigh muscles. Data are means ± SD (n = 5, ***P < 0.001). Histological analysis by hematoxylin and eosin staining of turpentine oil-untreated (E) and treated (F) muscles. Scale bar = 1 mm. Figure S3 The accumulation levels in bone and tumor of [11C]d4T, [11C]AZT, and [11C]4DST. Thigh bones and tumors were collected after 80 min PET probe injection. Radioactivities in these tissues were measured by γ-well counter. The graph in (A) shows the %ID/g for tumor tissue and bone. Data are presented as means ± SD (n = 4 to 6). **P < 0.01 vs. [11C]AZT and [11C]d4T injected mouse. †P < 0.01 vs. [11C]d4T injected mouse. The graph in (C) shows the ratio of tumor-to-bone uptake of the labeled probes. *P < 0.05 vs. [11C]4DST injected mice. **P < 0.01 vs. [11C]d4T injected mice

Synthesis of ¹¹C‑Labeled Thiamine and Fursultiamine for in Vivo Molecular Imaging of Vitamin B₁ and Its Prodrug Using Positron Emission Tomography

To enable in vivo analysis of the kinetics of vitamin B₁ (thiamine) and its derivatives by positron emission tomography (PET), ¹¹C-labeled thiamine ([¹¹C]-<b>1</b>) has been synthesized. This was carried out via a rapid, multistep synthesis consisting of Pd⁰-mediated <i>C</i>-[¹¹C]­methylation of a thiazole ring for 3 min and benzylation with 5-(bromomethyl)­pyrimidine for 7 min. The [¹¹C]-<b>1</b> was also converted to ¹¹C-labeled fursultiamine ([¹¹C]-<b>2</b>), a prodrug of vitamin B₁, by disulfide formation with <i>S</i>-tetrahydrofurfurylthiosulfuric acid sodium salt. Characterization of [¹¹C]-<b>1</b> and [¹¹C]-<b>2</b> showed them to be suitable for use as PET probes for in vivo pharmacokinetic and medical studies. The total durations of the preparations of [¹¹C]-<b>1</b> and [¹¹C]-<b>2</b> were shorter than 60 and 70 min, respectively. The [¹¹C]­CH₃I-based decay-corrected radiochemical yields of [¹¹C]-<b>1</b> and [¹¹C]-<b>2</b> were 9–16% and 4–10%, respectively. The radioactivities of the final injectable solutions of [¹¹C]-<b>1</b> and [¹¹C]-<b>2</b> were 400–700 and 100–250 MBq, respectively. The radiochemical purity of both [¹¹C]-<b>1</b> and [¹¹C]-<b>2</b> was 99%, and the chemical purities of [¹¹C]-<b>1</b> and [¹¹C]-<b>2</b> were 99% and 97–99%, respectively. In vivo PET imaging of normal rats was illustrated by the distribution of [¹¹C]-<b>1</b> and [¹¹C]-<b>2</b> following intravenous injection