Élastographie par ultrasons en imagerie cancérologique

Ultrasonic High-Resolution Imaging and Acoustic Tweezers Using Ultrahigh Frequency Transducer: Integrative Single-Cell Analysis

Ultrasound imaging is a highly valuable tool in imaging human tissues due to its non-invasive and easily accessible nature. Despite advances in the field of ultrasound research, conventional transducers with frequencies lower than 20 MHz face limitations in resolution for cellular applications. To address this challenge, we employed ultrahigh frequency (UHF) transducers and demonstrated their potential applications in the field of biomedical engineering, specifically for cell imaging and acoustic tweezers. The lateral resolution achieved with a 110 MHz UHF transducer was 20 μm, and 6.5 μm with a 410 MHz transducer, which is capable of imaging single cells. The results of our experiments demonstrated the successful imaging of a single PC-3 cell and a 15 μm bead using an acoustic scanning microscope equipped with UHF transducers. Additionally, the dual-mode multifunctional UHF transducer was used to trap and manipulate single cells and beads, highlighting its potential for single-cell studies in areas such as cell deformability and mechanotransduction.

Early diagnosis of prostate cancer by citrate determination in urine with europium-oxytetracycline complex

Normal prostate tissue contains high levels of citrate. In the presence of prostate cancer, the citrate level is diminished. In this paper we show that it is possible to use europium-oxytetracycline complex as a citrate fluorescent probe and consequently as a prostate cancer probe. We analyzed normal nude male mice urine and urine from nude male mice in which prostate cancer was induced by intraprostatic inoculation of DU145 cells. The urine samples were collected from the animals at the 7th, 14th, 21st, and 35th days after the surgery procedures. The intensity of europium emission at 615 nm in europium-oxytetracycline complex in the presence of citrate increases linearly. The citrate concentrations were determined from a calculated calibration curve. A concentration decrease in malignant prostate urine from the normal (PBS group) urine value from ~8.0 mM to ~2.4 mM (tumor group at 35th day) was found. The obtained results indicated that europium-oxytetracycline provides a significant biomarker for prostate cancer detection with a direct, accurate, noninvasive, and non-enzymatic method for measurement of citrate in biological fluids.

3-D photoacoustic and pulse echo imaging of prostate tumor progression in the mouse window chamber

Understanding the tumor microenvironment is critical to characterizing how cancers operate and predicting their response to treatment. We describe a novel, high-resolution coregistered photoacoustic (PA) and pulse echo (PE) ultrasound system used to image the tumor microenvironment. Compared to traditional optical systems, the platform provides complementary contrast and important depth information. Three mice are implanted with a dorsal skin flap window chamber and injected with PC-3 prostate tumor cells transfected with green fluorescent protein. The ensuing tumor invasion is mapped during three weeks or more using simultaneous PA and PE imaging at 25 MHz, combined with optical and fluorescent techniques. Pulse echo imaging provides details of tumor structure and the surrounding environment with 100-μm(3) resolution. Tumor size increases dramatically with an average volumetric growth rate of 5.35 mm(3)/day, correlating well with 2-D fluorescent imaging (R = 0.97, p < 0.01). Photoacoustic imaging is able to track the underlying vascular network and identify hemorrhaging, while PA spectroscopy helps classify blood vessels according to their optical absorption spectrum, suggesting variation in blood oxygen saturation. Photoacoustic and PE imaging are safe, translational modalities that provide enhanced depth resolution and complementary contrast to track the tumor microenvironment, evaluate new cancer therapies, and develop molecular contrast agents in vivo.