The Roles of Hypoxia Imaging Using 18F-Fluoromisonidazole Positron Emission Tomography in Glioma Treatment

Abstract

Glioma is the most common malignant brain tumor. Hypoxia is closely related to the malignancy of gliomas, and positron emission tomography (PET) can noninvasively visualize the degree and the expansion of hypoxia. Currently, 18F-fluoromisonidazole (FMISO) is the most common radiotracer for hypoxia imaging. The clinical usefulness of FMISO PET has been established; it can distinguish glioblastomas from lower-grade gliomas and can predict the microenvironment of a tumor, including necrosis, vascularization, and permeability. FMISO PET provides prognostic information, including survival and treatment response information. Because hypoxia decreases a tumor’s sensitivity to radiation therapy, dose escalation to an FMISO-positive volume is an attractive strategy. Although this idea is not new, an insufficient amount of evidence has been obtained regarding this concept. New tracers for hypoxia imaging such as 18F-DiFA are being tested. In the future, hypoxia imaging will play an important role in glioma management.

Difference in Acquired Radioresistance Induction Between Repeated Photon and Particle Irradiation

“…Given that hypoxic areas are primary niches of CSCs (85), and the tumor vasculature clearly changes after irradiation (86), imaging techniques used to identify hypoxic areas and well-vascularized areas in target tumors will likely be useful for planning secondary radiotherapy. Indeed, drugs targeting hypoxic areas have been developed (87, 88), and tumor blood vessels can be visualized by contrast-enhanced magnetic resonance imaging (89).…”

Biological Guided Carbon-Ion Microporous Radiation to Tumor Hypoxia Area Triggers Robust Abscopal Effects as Open Field Radiation

“…Nevertheless, the value of partial volume CIRT targeting hypoxic region(s) of a tumor under imaging guidance, as well as its effect of inducing RIAEs, have not been well investigated. 18 F-Fluoromisonidazole ( 18 F-FMISO) as hypoxia PET imaging probe has commonly been applied for hypoxic imaging in clinic, and will occur redox reactions under the action of xanthine oxidase and stably combine with some cellular components, thereby reflecting the degree of hypoxia in solid tumors (34,35). Herein, we developed a type of microporous radiation technique of CIRT (CI-MPR), guided by 18 F-FMISO PET/computerized tomography (CT), for partial volume radiation targeting the hypoxia area of a tumor and investigated its capability of inducing abscopal effects.…”

Coregistration of Magnetic Resonance and [18F] Fludeoxyglucose–Positron Emission Tomography Imaging for Stereotactic Radiation Therapy Planning: Case Report in a Previously Irradiated Brain Metastasis With Recurrent Tumor and Radiation Necrosis

“…However, confounding influences of FDG-PET false positive (from inflammation and stroke) or negative results with reported specificity and sensitivity (86% and 80%, respectively) in irradiated BMs must be considered when incorporating FDG-PET into treatment planning. 18 For instance, MR perfusion 19 [18-F]fluoromisonidazole-PET (hypoxia imaging) 20 and fluorothymidine F-18 PET (proliferation imaging) 21 and alternative amino acid PET tracers, such as [ 11 C]-methionine (MET-PET) or [F] fluoroethyl-L-tyrosine, which reduce cortical background 22 or translocator protein-18 kDa-PET, which is specific for inflammation, 23 may prove to have advantages over FDG-PET in SRS treatment planning to delineate tumor from RN. Finally, as opposed to PET-CT or PET alone, the use of PET-MRI may enhance coregistration and streamline the incorporation of PET into SRS treatment planning.…”