Larger 18F-fluoroboronotyrosine (FBY) active volume beyond MRI contrast enhancement in diffuse gliomas than in circumscribed brain tumors

Abstract

Background To investigate the relationship between 18F-fluoroboronotyrosine (FBY) positron emission tomography (PET)- and magnetic resonance imaging (MRI)-defined tumor volumes in contrast-enhanced diffuse gliomas and circumscribed brain tumors. Methods A total of 16 diffuse gliomas and 7 circumscribed brain tumors were included, and two types of three-dimensional regions of interest (ROIs), namely, MRI-based ROI (ROIMRI) and FBY-based ROI (ROIFBY), were semiautomatically defined. The overlap volume and DICE score were calculated to reveal the spatial relationship between the ROIMRI and ROIFBY. Results The ROIMRI was smaller than the ROIFBY and was mostly contained by the ROIFBY with an overlap volume of 0.995 ± 0.006 in the whole population. A significant difference in the DICE score was observed between circumscribed tumors and diffuse tumors (0.886 ± 0.026 vs. 0.684 ± 0.165, p = 0.004), and for the regions that have increased FBY metabolism but not MRI contrast enhancement, diffuse tumors and circumscribed tumors showed similar SUVmean values (0.630 ± 0.19 vs. 0.671 ± 0.18, p = 0.625). Conclusion FBY uptake beyond contrast enhancement is more significant in diffuse tumors than in circumscribed tumors, which may aid the delineation of active tumor areas and facilitate boron neutron capture therapy.

86Y-Labeled Albumin-Binding Fibroblast Activation Protein Inhibitor for Late-Time-Point Cancer Diagnosis

“…The clinical value of FAPI PET has been proven for differential diagnosis, TNM staging, radiation planning, and treatment response evaluation as a replacement or complementary tool for 18 F-FDG PET and other imaging modalities. − Although preliminary studies on FAP-targeted radionuclides reported acceptable safety profiles and mixed responses in certain patients, the relatively fast clearance of FAPIs compared with the half-life of treatment nuclides limits the achievable radiation dose. In preclinical studies, 93% of 225 Ac-FAPI-04 was excreted through urine and feces 24 h after administration, and tumor uptake was 0.3%ID/g at 3 h and 0.1%ID/g at 24 h for 177 Lu-FAPI-46 and 225 Ac-FAPI-46 .…”

Bioorthogonal chemistry for prodrug activation in vivo

“…5D). 48,50,51 The studies demonstrated that BAAs are biocompatible, rapidly cleared in normal tissue, and leave no residue in the body, thus laying a solid foundation for their use as bioorthogonal reaction activators. The clearly defined pharmacokinetics facilitates optimal timing and dosing of the activator and prodrug administration.…”

Preclinical and Clinical Use of Indigenously Developed 99mTc-Diethylenetriaminepentaacetic Acid-Bis-Methionine: l-Type Amino Acid Transporter 1-Targeted Single Photon Emission Computed Tomography Radiotracer for Glioma Management

“…80 FBY shows promise in assessing brain tumors, and its metabolism has been found to be significantly increased in most neoplasms, whereas it remained low in non-cancerous lesions. 79,80 In comparison to other amino acid PET tracers, like FET and 4borono-2-18 F-fluorophenylalanine (FBPA), FBY exhibited reduced background activity, with mean and maximum SUV values of 0.037 and 0.116, respectively, allowing a clearer visualization of tumors, and may help in identifying small lesions and defining treatment targets. 80 Preclinical and clinical studies show that the energyindependent LAT-1 system preferentially takes up 99m Tcmethionine, referring to 99m Tc-DTPA-bis(Met) in tumor cells.…”

“…79,80 In comparison to other amino acid PET tracers, like FET and 4borono-2-18 F-fluorophenylalanine (FBPA), FBY exhibited reduced background activity, with mean and maximum SUV values of 0.037 and 0.116, respectively, allowing a clearer visualization of tumors, and may help in identifying small lesions and defining treatment targets. 80 Preclinical and clinical studies show that the energyindependent LAT-1 system preferentially takes up 99m Tcmethionine, referring to 99m Tc-DTPA-bis(Met) in tumor cells. In a preliminary study, it localizes selectively in recurrent/ residual gliomas and has excellent target-to-non-target (T/NT) image contrast.…”

“…This is due to the upregulation of system L transport in glioma cells and is active at the intact BBB. − [ 18 F]­Fluoro­borono­tyrosine (FBY) is a boron-derived tyrosine with therapeutic and diagnostic potential that is dependent on LAT-1 for its transportation . Most malignant brain tumors exhibit increased FBY activity, and recurrent gliomas, primary GBM and metastatic brain tumors, all showed high tumor-to-background ratios, which may aid in the stratification of malignancy and future boron neutron capture therapy . FBY shows promise in assessing brain tumors, and its metabolism has been found to be significantly increased in most neoplasms, whereas it remained low in non-cancerous lesions. , In comparison to other amino acid PET tracers, like FET and 4-borono-2- 18 F-fluoro­phenyl­alanine (FBPA), FBY exhibited reduced background activity, with mean and maximum SUV values of 0.037 and 0.116, respectively, allowing a clearer visualization of tumors, and may help in identifying small lesions and defining treatment targets …”