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Maladaptive use of the Internet results in Internet addiction (IA), which is associated with various negative consequences. Molecular and functional imaging techniques have been increasingly used for analysis of neurobiological changes and neurochemical correlates of IA. This review summarizes molecular and functional imaging findings on neurobiological mechanisms of IA, focusing on magnetic resonance imaging (MRI) and nuclear imaging modalities including positron emission tomography (PET) and single photon emission computed tomography (SPECT). MRI studies demonstrate that structural changes in frontal cortex are associated with functional abnormalities in Internet addicted subjects. Nuclear imaging findings indicate that IA is associated with dysfunction of the brain dopaminergic systems. Abnormal dopamine regulation of the prefrontal cortex (PFC) could underlie the enhanced motivational value and uncontrolled behavior over Internet overuse in addicted subjects. Further investigations are needed to determine specific changes in the Internet addictive brain, as well as their implications for behavior and cognition.

Spinal cord injury (SCI) is a serious disease of the center nervous system (CNS). It is a devastating injury with sudden loss of motor, sensory, and autonomic function distal to the level of trauma and produces great personal and societal costs. Currently, there are no remarkable effective therapies for the treatment of SCI. Compared to traditional treatment methods, stem cell transplantation therapy holds potential for repair and functional plasticity after SCI. However, the mechanism of stem cell therapy for SCI remains largely unknown and obscure partly due to the lack of efficient stem cell trafficking methods. Molecular imaging technology including positron emission tomography (PET), magnetic resonance imaging (MRI), optical imaging (i.e., bioluminescence imaging (BLI)) gives the hope to complete the knowledge concerning basic stem cell biology survival, migration, differentiation, and integration in real time when transplanted into damaged spinal cord. In this paper, we mainly review the molecular imaging technology in stem cell therapy for SCI.

Positron emission tomography (PET) is a powerful noninvasive tool for acquisition of the physiological parameters in human and animals with the help of PET tracers. Among all the PET tracers, radiolabeled peptides have been widely explored for cancer-related receptor imaging due to their high affinity and specificity to receptors. But radiochemistry procedures for production of peptide-based PET tracers are usually complex, which makes large-scale clinical studies relatively challenging. New radiolabeling technologies which could simplify synthesis and purification procedures, are extremely needed. Over the last decade, microfluidics and lab-on-a-chip (LOC) technology have boomed as powerful tools in the field of organic chemistry, which potentially provide significant help to the PET chemistry. In this minireview, microfluidic radiolabeling technology is described and its application for synthesis of peptide-based PET tracers is summarized and discussed.

With the speeding tendency of aging society, human neurological disorders have posed an ever increasing threat to public health care. Human neurological diseases include ischemic brain injury, Alzheimer’s disease, Parkinson’s disease, and spinal cord injury, which are induced by impairment or specific degeneration of different types of neurons in central nervous system. Currently, there are no more effective treatments against these diseases. Traditional Chinese medicine (TCM) is focused on, which can provide new strategies for the therapy in neurological disorders. TCM, including Chinese herb medicine, acupuncture, and other nonmedication therapies, has its unique therapies in treating neurological diseases. In order to improve the treatment of these disorders by optimizing strategies using TCM and evaluate the therapeutic effects, we have summarized molecular imaging, a new promising technology, to assess noninvasively disease specific in cellular and molecular levels of living models in vivo, that was applied in TCM therapy for neurological diseases. In this review, we mainly focus on applying diverse molecular imaging methodologies in different TCM therapies and monitoring neurological disease, and unveiling the mysteries of TCM.

Stem cells have been proposed as a promising therapy for treating stroke. While several studies have demonstrated the therapeutic benefits of stem cells, the exact mechanism remains elusive. Molecular imaging provides the possibility of the visual representation of biological processes at the cellular and molecular level. In order to facilitate research efforts to understand the stem cells therapeutic mechanisms, we need to further develop means of monitoring these cells noninvasively, longitudinally and repeatedly. Because of tissue depth and the blood-brain barrier (BBB), in vivo imaging of stem cells therapy for stroke has unique challenges. In this review, we describe existing methods of tracking transplanted stem cells in vivo, including magnetic resonance imaging (MRI), nuclear medicine imaging, and optical imaging (OI). Each of the imaging techniques has advantages and drawbacks. Finally, we describe multimodality imaging strategies as a more comprehensive and potential method to monitor transplanted stem cells for stroke.

The growing use of molecular imaging helps to control and monitor dosage for increased safety and effectiveness. Molecular imaging agents become the scientific tools for moving a concept from bench work to clinic product development. This special issue provides original research and review of new trends in molecular imaging agent development. Among clinic molecular imaging modalities, radionuclide imaging technique is the most sensitive and could provide target-specific information. The radiotracer could non-invasively assess disease treatment endpoints which used to rely almost exclusively on biopsies and histopathological assays. L.-H. Shen et al. (Taiwan) reviewed molecular imaging in the diagnosis and management of CNS disorders. F.-L. Kong et al. (USA), N. Tsao et al. (USA), and C.-L. Ho et al. (Taiwan) report pharmacokinetics and dosimetry of molecular imaging compounds in oncology. M.-H. Liao et al. (Taiwan), X. Wang et al. (China), C. Wu et al. (China) and M. Tian et al. (USA) reported that molecular imaging techniques play a major role in the development of novel therapies since they measure target expressions (apoptosis, glycolysis) as well as function, pathway activities, and cell migration in the intact organism. Y.-F. Wang et al. and M.-Y. Chao et al. (Taiwan) described the kit probe for 99mTc-labeling which is crucial for centralized drug process. The kit probe may allow theranostic concept. A theranostic agent would be more accurate in the evaluation of patient response to treatment. The radiotracer could also be used for radionuclide therapy as reported by C. Wang et al. (China). Hybrid molecular imaging modalities (PET/CT, SPECT/CT) provide high-sensitivity functional and high-resolution anatomical imaging which are important in design-personalized treatment. M.-C. Chen et al. (Taiwan) reported the value of using I-131 NP-59 SPECT/CT to diagnose patients with subclinical or atypical features of primary aldosteronism. To proof of concept for molecular biology findings using different imaging modalities (optical, sonography) were described by Z. Pu et al. (China). In summary, molecular imaging enables the comprehensive characterization of therapeutic intervention and can be used in preclinical studies, pharmacokinetic studies, dose-finding studies, and proof-of-concept studies. Molecular imaging technologies promote the discovery and development of personalized medicine. Hong Zhang Mei Tian Carrio Ignasi Zhen Cheng Lie-Hang Shen David J. Yang