Secondary Logo

Journal Logo

Interesting Images

18F-FBPA PET in Sarcoidosis

Comparison to Inflammation-Related Uptake on FDG PET

Watabe, Tadashi MD, PhD∗,†; Shimamoto, Hiroaki DDS, PhD; Naka, Sadahiro§; Kamiya, Takashi PhD§; Murakami, Shumei DDS, PhD

Author Information
doi: 10.1097/RLU.0000000000003274
  • Open

Abstract

FIGURE 1
FIGURE 1:
A 68-year-old man with tongue cancer and sarcoidosis underwent high-dose-rate interstitial brachytherapy to the primary cancer lesion (54 Gy/9 fr). Ten days later, 18F-FDG PET revealed high FDG uptakes in the mediastinal and hilar lymph nodes, suggesting active inflammation in a sarcoidosis granuloma (AC, arrows; SUVmax, 8.05). In addition, 18F-FDG uptake was also seen in the pathway of the applicator implantation and radiation-induced inflammation, which was not observed in the pretreatment 18F-FDG PET (D and E, arrowheads). Uptake in the primary tumor region was not clear.
FIGURE 2
FIGURE 2:
The following day after 18F-FDG PET, 18F-fluoro-boronophenylalanine (FBPA) PET was performed. No significant FBPA uptake was observed in the mediastinal and hilar lymph nodes (AC, arrows), or in the inflammatory lesion from the right side of the tongue to the right submandibular region (D and E, arrowheads), suggesting its specificity as an l-type amino acid transporter 1 (LAT1).1–4 LAT1 is a cancer-type amino acid transporter that shows minimal expression in inflammatory lesions.1,5 18F-α-methyl tyrosine, another LAT1-specific PET probe, was also reported to show no significant uptake in sarcoidosis lesions.6–8 18F-FBPA PET can be used for precise evaluation of oncology patients in which the differentiation between reactive uptake and metastatic uptake is inconclusive on 18F-FDG PET.

REFERENCES

1. Watabe T, Ikeda H, Nagamori S, et al. 18F-FBPA as a tumor-specific probe of L-type amino acid transporter 1 (LAT1): a comparison study with 18F-FDG and 11C-methionine PET. Eur J Nucl Med Mol Imaging. 2017;44:321–331.
2. Beshr R, Isohashi K, Watabe T, et al. Preliminary feasibility study on differential diagnosis between radiation-induced cerebral necrosis and recurrent brain tumor by means of [(18)F]fluoro-borono-phenylalanine PET/CT. Ann Nucl Med. 2018;32:702–708.
3. Yoshimoto M, Kurihara H, Honda N, et al. Predominant contribution of l-type amino acid transporter to 4-borono-2-(18)F-fluoro-phenylalanine uptake in human glioblastoma cells. Nucl Med Biol. 2013;40:625–629.
4. Aoki M, Watabe T, Nagamori S, et al. Distribution of LAT1-targeting PET tracer was independent of the tumor blood flow in rat xenograft models of C6 glioma and MIA PaCa-2. Ann Nucl Med. 2019;33:394–403.
5. Kanai Y, Segawa H, Miyamoto K, et al. Expression cloning and characterization of a transporter for large neutral amino acids activated by the heavy chain of 4F2 antigen (CD98). J Biol Chem. 1998;273:23629–23632.
6. Wiriyasermkul P, Nagamori S, Tominaga H, et al. Transport of 3-fluoro-l-alpha-methyl-tyrosine by tumor-upregulated l-type amino acid transporter 1: a cause of the tumor uptake in PET. J Nucl Med. 2012;53:1253–1261.
7. Wei L, Tominaga H, Ohgaki R, et al. Specific transport of 3-fluoro-l-alpha-methyl-tyrosine by LAT1 explains its specificity to malignant tumors in imaging. Cancer Sci. 2016;107:347–352.
8. Yudistiro R, Arisaka Y, Tokue A, et al. Differentiation of sarcoidosis-lymphoma syndrome lesions: a case report on the use of two different positron emission tomography tracers. BMC Med Imaging. 2016;16:1.
Keywords:

18F-FBPA; 18F-FDG; sarcoidosis

Copyright © 2020 The Author(s). Published by Wolters Kluwer Health, Inc.