As drug carriers, magnetic nanoparticles can specifically bind to tumors and have the potential for targeted therapy. It is of great significance to explore non-invasive imaging methods that can detect the distribution of magnetic nanoparticles. Based on the mechanism that magnetic nanoparticles can generate ultrasonic waves through the pulsed magnetic field excitation, the sound pressure wave equation containing the concentration information of magnetic nanoparticles was derived. Using the finite element method and the analytical solution, the consistent transient pulsed magnetic field was obtained. A three-dimensional simulation model was constructed for the coupling calculation of electromagnetic field and sound field. The simulation results verified that the sound pressure waveform at the detection point reflected the position of magnetic nanoparticles in biological tissue. Using the sound pressure data detected by the ultrasonic transducer, the B-scan imaging of the magnetic nanoparticles was achieved. The maximum error of the target area position was 1.56%, and the magnetic nanoparticles regions with different concentrations were distinguished by comparing the amplitude of the boundary signals in the image. Studies in this paper indicate that B-scan imaging can quickly and accurately obtain the dimensional and positional information of the target region and is expected to be used for the detection of magnetic nanoparticles in targeted therapy.
The detection rates of pulmonary nodules and early-stage lung cancer are rising year on year, which underscores the clinical value of sublobar resections including lung segmentectomy. CT-based three-dimensional reconstruction can intuitively visualize the anatomical courses and variants of bronchial and pulmonary vascular structures (arteries and veins), thereby providing accurate guidance for preoperative localization, surgical planning and intraoperative identification. This article systematically reviews the anatomical classification patterns of the bronchi and pulmonary vessels in the right upper, middle, and lower lobes at the segmental and subsegmental levels, and summarizes clinically significant variations, including tracheal bronchus, common arterial trunk, right top pulmonary vein, lingular-like bronchial configuration of the middle lobe, ectopic venous drainage, the subsuperior segment ("star segment") variation, and the relationship of B7/A7 to the inferior pulmonary vein, analyzing their impact on intraoperative anatomical judgment and treatment strategies for bronchial and vessels. This review aims to provide an anatomical basis and clinical reference for individualized precise segmentectomy and complex sublobar resection, so as to maximize preservation of pulmonary function while ensuring oncologic radicality and reducing the risk of surgical complications.