Application of Indocyanine Green Fluorescence Imaging in Assisting Biopsy of Musculoskeletal Tumors.

(1) Background: Biopsies are the gold standard for the diagnosis of musculoskeletal tumors. In this study, we aimed to explore whether indocyanine green near-infrared fluorescence imaging can assist in the biopsy of bone and soft tissue tumors and improve the success rate of biopsy. (2) Method: We recruited patients with clinically considered bone and soft tissue tumors and planned biopsies. In the test group, indocyanine green (0.3 mg/kg) was injected. After identifying the lesion, a near-infrared fluorescence camera system was used to verify the ex vivo specimens of the biopsy in real time. If the biopsy specimens were not developed, we assumed that we failed to acquire lesions, so the needle track and needle position were adjusted for the supplementary biopsy, and then real-time imaging was performed again. Finally, we conducted a pathological examination. In the control group, normal biopsy was performed. (3) Results: The total diagnosis rate of musculoskeletal tumors in the test group was 94.92% (56/59) and that in the control group was 82.36% (42/51). In the test group, 14 cases were not developed, as seen from real-time fluorescence in the core biopsy, and then underwent the supplementary biopsy after changing the puncture direction and the location of the needle channel immediately, of which 7 cases showed new fluorescence. (4) Conclusions: Using the near-infrared fluorescence real-time development technique to assist the biopsy of musculoskeletal tumors may improve the accuracy of core biopsy and help to avoid missed diagnoses, especially for some selected tumors.

Construct Validity of a Novel Assessment System for Laparoscopic Suture Accuracy Based on Stereoscopy.

BACKGROUND: An accurate and objective measuring tool is lacking for laparoscopic suture accuracy assessment in simulation training. We designed and developed the suture accuracy testing system (SATS) and aimed to determine its construct validity in this study. METHODS: Twenty laparoscopic experts and 20 novices were recruited to perform a suturing task in three sessions using traditional laparoscopic instruments (Tra. session), a handheld multi-degree-of-freedom (MDoF) laparoscopic instrument (MDoF session) and a surgical robot (Rob. session), respectively. The needle entry and exit errors were calculated using the SATS and compared between the two groups. RESULTS: No significant difference of the needle entry error was found in all comparisons. As for the needle exit error, the value of the novice group was significantly higher than that of the expert group in Tra. session (3.48 ± 0.61 mm vs. 0.85 ± 0.14 mm; p = 1.451e-11) and MDoF session (2.65 ± 0.41 mm vs. 1.06 ± 0.17 mm; p = 1.451e-11) but not in Rob. session (0.51 ± 0.12 mm vs. 0.45 ± 0.08 mm; p = 0.091). CONCLUSIONS: The SATS demonstrates construct validity. Surgeons' experience in conventional laparoscopic instruments could be transferred to the MDoF instrument. Surgical robot helps to improve suture accuracy and may bridge the experience gap between laparoscopic experts and novices in basic exercises.

Effect of Thermal Ablation on Growth Plates: A Study to Explore the Thermal Threshold of Rabbit Growth Plates During Microwave Ablation.

PURPOSE: To explore the temperature threshold of thermal damage to growth plates. METHODS: Nine rabbits were divided into three groups for femoral ablation, exposing the growth plate to different temperatures (T1 = 43-45 °C; T2 = 46-48 °C; T3 = 49-51 °C). After 5 weeks, the changes in the femurs were assessed by macroscopic images, micro-CT, haematoxylin and eosin staining, and immunohistochemistry of Col2a1 (type II collagen). At the cellular level, rabbit epiphyseal chondrocytes were exposed to 37 °C, 44 °C, 47 °C and 50 °C for 5 min. Then, proliferation and chondrogenic differentiation were detected. RESULTS: The rabbits in the T2 and T3 groups developed length discrepancies and axial deviations of femurs, abnormal newly formed bone in the marrow cavity, disorganized growth plates and decreased Col2a1 expression. At the cellular level, the cells exposed to 47 °C and 50 °C for 5 min showed decreased viability, increased apoptosis, decreased extracellular matrix synthesis and decreased matrix mineralization. However, the changes in rabbits in the T1 group and cells at 44 °C did not show a significant difference. CONCLUSION: The ablation of growth plates at temperatures above 45 °C for 5 min results in decreased chondrocyte viability and disorganized growth plates, leading to growth disturbances. Further studies are warranted to confirm these promising initial results.

High detection efficiency silicon single-photon detector with a monolithic integrated circuit of active quenching and active reset.

Silicon single-photon detectors (SPDs) are key devices for detecting single photons in the visible wavelength range. Photon detection efficiency (PDE) is one of the most important parameters of silicon SPDs, and increasing PDE is highly required for many applications. Here, we present a practical approach to increase the PDE of silicon SPDs with a monolithic integrated circuit of active quenching and active reset (AQAR). The AQAR integrated circuit is specifically designed for thick silicon single-photon avalanche diodes (SPADs) with high breakdown voltage (250 V-450 V) and then fabricated via the process of high-voltage 0.35-µm bipolar-CMOS-DMOS. The AQAR integrated circuit implements the maximum transition voltage of ∼68 V with 30 ns quenching time and 10 ns reset time, which can easily boost PDE to the upper limit by regulating the excess bias up to a high enough level. By using the AQAR integrated circuit, we design and characterize two SPDs with the SPADs disassembled from commercial products of single-photon counting modules (SPCMs). Compared with the original SPCMs, the PDE values are increased from 68.3% to 73.7% and 69.5% to 75.1% at 785 nm, respectively, with moderate increases in dark count rate and afterpulse probability. Our approach can effectively improve the performance of the practical applications requiring silicon SPDs.