Coupling Electronic and Phonon Thermal Transport in Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) Nanofibers.

The thermal transport of Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) nanofiber is contributed by the electronic component of thermal conduction and the phonon component of thermal conduction. The relationship between the electrical conductivity and thermal conductivity of these conducting polymers is of great interest in thermoelectric energy conversation. In this work, we characterized the axial electrical conductivities and thermal conductivities of the single PEDOT:PSS nanofibers and found that the Lorenz number L is larger than Sommerfeld value L0 at 300 K. In addition, we found that the L increased significantly in the low-temperature region. We consider that this trend is due to the bipolar contribution of conducting polymers with low-level electrical conductivity and the increasing trend of the electronic contribution to thermal conductivity in low-temperature regions.

Endoscopic Cerenkov luminescence imaging and image-guided tumor resection on hepatocellular carcinoma-bearing mouse models.

Detecting deep tumors inside living subject is still challenging for Cerenkov luminescence imaging (CLI). In this study, a high-sensitivity endoscopic CLI (ECLI) system was developed with a dual-mode deep cooling approach to improve the imaging sensitivity. System was characterized through a series of ex vivo studies. Furthermore, subcutaneous and orthotropic human hepatocellular carcinoma (HCC) mouse models were established for ECLI guided tumor resection in vivo. The results showed that the ECLI system had spatial resolution (62.5 µm) and imaging sensitivity (6.29 × 10-2 kBq/µl 18F-FDG). The in vivo experimental data from the HCC mouse models demonstrated that the system was effective to intraoperatively guide the surgery of deep tumors such as liver cancer. Overall, the developed system exhibits promising potential for the applications of tumor precise resection and novel nanoprobe based optical imaging.

A Novel Endoscopic Cerenkov Luminescence Imaging System for Intraoperative Surgical Navigation.

Cerenkov luminescence imaging is an emerging optical technique for imaging the distribution of radiopharmaceuticals in vivo. However, because of the light scattering effect, it cannot obtain optical information from deep internal organs. To overcome this challenge, we established a novel endoscopic Cerenkov luminescence imaging system that used a clinically approved laparoscope and an electron-multiplying charge-coupled device camera. We assessed the performance of the system through a series of in vitro and in vivo experiments. The results demonstrated superior superficial imaging resolution (0.1 mm), a large field of view (500 mm2 with 10 mm imaging distance), and superb imaging sensitivity (imaging 1 µCi) of our system. It captured the weak Cerenkov signal from internal organs successfully and was applied to intraoperative surgical navigation of tumor resection. It offered objective information of the tumor location and tumor residual during the surgical operation. This technique holds great potential for clinical translation.

Multispectral hybrid Cerenkov luminescence tomography based on the finite element SPn method.

Cerenkov luminescence tomography (CLT) is a promising tool that enables three-dimensional noninvasive in vivo detection of radiopharmaceuticals. Conventionally, multispectral information and diffusion theory were introduced to achieve whole-body tomographic reconstruction. However, the diffusion theory inevitably causes systematic error in blue bands of the electromagnetic spectrum due to high-tissue absorption, and CL has a blue-weighted broad spectrum. Therefore, it is challenging to improve the accuracy of CLT. The performance of the n -order simplified spherical harmonics approximation (SPn) in different spectra is evaluated, and a multispectral hybrid CLT based on the combination of different SPn models is proposed to handle the Cerenkov photon transport problem in complex media. The in vivo xenograft experiment shows that this approach can effectively improve the quality and accuracy of the reconstructed light source. We believe that the new reconstruction method will advance the development of CLT for more in vivo imaging applications

In vivo nanoparticle-mediated radiopharmaceutical-excited fluorescence molecular imaging.

Cerenkov luminescence imaging utilizes visible photons emitted from radiopharmaceuticals to achieve in vivo optical molecular-derived signals. Since Cerenkov radiation is weak, non-optimum for tissue penetration and continuous regardless of biological interactions, it is challenging to detect this signal with a diagnostic dose. Therefore, it is challenging to achieve useful activated optical imaging for the acquisition of direct molecular information. Here we introduce a novel imaging strategy, which converts γ and Cerenkov radiation from radioisotopes into fluorescence through europium oxide nanoparticles. After a series of imaging studies, we demonstrate that this approach provides strong optical signals with high signal-to-background ratios, an ideal tissue penetration spectrum and activatable imaging ability. In comparison with present imaging techniques, it detects tumour lesions with low radioactive tracer uptake or small tumour lesions more effectively. We believe it will facilitate the development of nuclear and optical molecular imaging for new, highly sensitive imaging applications.

From PET/CT to PET/MRI: advances in instrumentation and clinical applications.

Multimodality imaging of positron emission tomography/computed tomography (PET/CT) provides both metabolic information and the anatomic structure, which is significantly superior to either PET or CT alone and has greatly improved its clinical applications. Because of the higher soft-tissue contrast of magnetic resonance imaging (MRI) and no extra ionizing radiation, PET/MRI imaging is the hottest topic currently. PET/MRI is swiftly making its way into clinical practice. However, it has many technical difficulties to overcome, such as photomultiplier tubes, which cannot work properly in a magnetic field, and the inability to provide density information on the object for attenuation correction. This paper introduces the technique process of PET/MRI and summarizes its clinical applications, including imaging in oncology, neurology, and cardiology.