Positron emission tomography/computed tomography (PET/CT) has dramatically altered the landscape of noninvasive glioma evaluation, offering complementary insights to those gained through magnetic resonance imaging (MRI). PET/CT scans enable a multifaceted analysis of glioma biology, supporting clinical applications from grading and differential diagnosis to mapping the full extent of tumors and planning subsequent treatments and evaluations. With a broad array of specialized radiotracers, researchers and clinicians can now probe various biological characteristics of gliomas, such as glucose utilization, cellular proliferation, oxygen deficiency, amino acid trafficking, and reactive astrogliosis. This review aims to provide a recent update on the application of versatile PET/CT radiotracers in glioma research and clinical practice.

Astrocytes primarily maintain physiological brain homeostasis. However, under various pathological conditions, they can undergo morphological, transcriptomic, and functional transformations, collectively referred to as reactive astrogliosis.Recent studies have accumulated lines of evidence that reactive astrogliosis plays a crucial role in the pathology of Alzheimer’s disease (AD). In particular, monoamine oxidase B, a mitochondrial enzyme mainly expressed in astrocytes, significantly contributes to neuronal dysfunction and neurodegeneration in AD brains. Moreover, it has been reported that reactive astrogliosis precedes other pathological hallmarks such as amyloid-beta plaque deposition and tau tangle formation in AD.Due to the early onset and profound impact of reactive astrocytes on pathology, there have been extensive efforts in the past decade to visualize these cells in the brains of AD patients using positron emission tomography (PET) imaging. In this review, we summarize the recent studies regarding the essential pathological importance of reactive astrocytes in AD and their application as a target for PET imaging.

The prevalence of thyroid cancer in pregnant women is unknown; however, given that thyroid cancer commonly develops in women, especially young women of childbearing age, new cases are often diagnosed during pregnancy. This recommendation summarizes the follow-up and treatment when thyroid cancer is diagnosed during pregnancy and when a woman with thyroid cancer becomes pregnant. If diagnosed in the first trimester, surgery should be postponed until after delivery, and the patient should be monitored with ultrasound. If follow-up before 24–26 weeks of gestation shows that thyroid cancer has progressed, surgery should be considered. If it has not progressed at 24–26 weeks of gestation or if papillary thyroid cancer is diagnosed after 20 weeks of pregnancy, surgery should be considered after delivery.

Based on the clinical, histopathological, and perioperative data of a patient with differentiated thyroid cancer (DTC), risk stratification based on their initial recurrence risk is a crucial follow-up (FU) strategy during the first 1–2 years after initial therapy. However, restratifiying the recurrence risk on the basis of current clinical data that becomes available after considering the response to treatment (ongoing risk stratification, ORS) provides a more accurate prediction of the status at the final FU and a more tailored management approach. Since the 2015 American Thyroid Association Management Guidelines for Adult Patients with Thyroid Nodules and DTC, the latest guidelines that include the National Comprehensive Cancer Network clinical practice and European Association for Medical Oncology guidelines have been updated to reflect several recent evidence in ORS and thyroid-stimulating hormone (TSH) suppression of DTC. The current clinical practice guideline was developed by extracting FU surveillance after the initial treatment section from the previous version of guidelines and updating it to reflect recent evidence. The current revised guideline includes recommendations for recent ORS, TSH target level based on risk stratification, FU tools for detection of recurrence and assessment of disease status, and long-term FU strategy for consideration of the disease status. These evidence-based recommendations are expected to avoid overtreatment and intensive FU of the majority of patients who will have a very good prognosis after the initial treatment of DTC patients, thereby ensuring that patients receive the most appropriate and effective treatment and FU options.