Introduction to the principle and application of small animal photoacoustic imaging technology The only true 3-D photoacoustic imaging system on the market Nexus 128 small animal photoacoustic imaging for 3D high-resolution, high-contrast photoacoustic imaging of small animals for cardiovascular disease (angiogenesis, myocarditis, thrombosis, myocardial infarction, etc.), lymph, tumor, nervous system, Frontier research in blood diseases, novel molecular probes (nano probes), hemoglobin concentration and blood oxygen saturation measurement and functional imaging will further enhance the research level and status of scientific research units in these fields. First, the technical principle Near-infrared small animal photoacoustic imaging is a new technology with broad prospects in basic research in biomedical research and disease-related applications. Biomedical research targeting animal models can avoid the risks brought by experiments in humans, overcome the shortcomings of long-term incubation and long duration of certain diseases, and can strictly control animal experimental conditions and reduce the impact of individual differences. One of the indispensable tools in research. Second, two different modes of photoacoustic imaging Third, the application of near-infrared small animal photoacoustic imaging system Many components in our body are endogenous contrast agents. For example, hemoglobin is a good endogenous contrast agent, and hemoglobin carrying oxygen will absorb more at other wavelengths, so according to this principle, light The sound can measure hemoglobin concentration and blood oxygen saturation. The soft tissue in the body and the neovascularization in the tumor are also good contrast agents. The principle of tumor angiogenesis is also based on the very active vascular activity, so the hemoglobin concentration is higher than the internal structure of the tumor, and the tumor can be implemented based on the photoacoustic wavelength of hemoglobin detection. Analysis of angiogenesis. Â Exogenous contrast agents, as long as they absorb between 680nm and 950nm, can be detected by photoacoustic imaging systems. For example, commonly used ICGs, almost all nanomaterials, etc., can be produced in photoacoustic systems. Good detection signal. For example, in order to study the dynamic distribution process of gold nanorods in mouse transplanted tumors, the animals were scanned every 15 minutes after the injection of the nano-probes, and the scan was performed 5 times for a total time of 75 minutes. The scanned photoacoustic image can be fused in the software and generate corresponding dynamic curves for our analysis. Since the muscles, bones, and proteins of the living organism have a certain degree of absorption in the near-infrared region, as an endogenous contrast agent, different photoacoustic signals can be presented under photoacoustic scanning, and thus can be used as a means of anatomical imaging. . In the photoacoustic imaging of the figure below, we can clearly see the various anatomical structures of the mouse. Â Â Â Â As you can see from the above figure, the steps to operate the Nexus 128 are very simple. The first step is the pretreatment of animals, animal anesthesia is carried out in an anesthesia box, and there are now numerous commercial systems that can perform anesthesia in small animals. The second step is to place the anesthetized animal on the animal tray. If there is a contrast agent, the contrast agent can be injected through the eye or tail vein at this time. The position is then placed and white light imaging is performed on the animal processing station to provide a visible light image for photoacoustic positioning. In the third step, the animal tray is moved to the Nexus 128, and the fixed position is fixed according to the position of the high position and the position, and the animal light sound scanning can be performed by closing the door. In summary, the Endra Small Animal Photoacoustic Imaging System is a new, non-invasive, in vivo imaging model that combines the high contrast properties of optical imaging with the high penetration depth of ultrasound imaging to provide high resolution and high contrast tissue imaging. . The Endra imaging system enables both endogenous structural imaging and higher contrast images with the aid of contrast enhancers. It can be applied to various research fields such as cardiovascular, drug metabolism, early diagnosis of diseases, gene expression research, stem cells and immunity, tumor biology, brain neurobiology, etc., to provide more reliable and comprehensive experimental data for scientific research. Full Body Massage,Body Massage Cost,Perfect Body Massage,Neck And Shoulder Massager Shenzhen Jie Zhong Lian Investment Co., Ltd. , https://www.meizons.com
Photoacoustic imaging is a landmark advanced molecular imaging research instrument for measuring the scientific research level and depth of scientific research in the fields of life science, basic medicine and chemistry in comprehensive universities. It is currently developing in China and is becoming a key subject in teaching, research and key disciplines. The necessary analytical testing methods for the construction of the room. In view of the fact that photoacoustic technology has better bio-tissue penetration than near-infrared technology, and has the characteristics of high resolution and no side effects, it is gradually becoming another research hotspot in the field of non-destructive testing of biological tissues.
When a beam of light is irradiated onto the biological tissue, the biological tissue absorbs the light energy to generate thermal expansion, and ultrasonic waves generate ultrasonic waves, and the amount of absorbed light energy determines the intensity of the generated ultrasonic waves. Different tissues will then produce ultrasound of different intensities, which can be used to distinguish between normal and diseased tissue. Photoacoustic imaging technology detects ultrasonic signals (this technology overcomes the insufficiency of optical imaging technology in imaging depth and resolution), reflecting the difference in optical energy absorption (complementary ultrasound imaging technology in terms of contrast and functionality) The defect), combined with the advantages of both optical and ultrasonic imaging techniques, enables high-resolution, high-contrast functional imaging of large depths of tissue.
From the perspective of photoacoustic imaging mode, the near-infrared photoacoustic system can be divided into two ways, one is based on the traditional slice-type 2-D imaging method, and the other is a true 3-D photoacoustic imaging system. The biggest difference between the two systems is that true 3-D imaging has exactly equal resolution for each directionality. In the case of a conventional slice-scanning system, a relatively narrow area in the center of each slice has a higher resolution, and an 80% edge area outside the slice center has a poor resolution. When these 3-D images are reconstructed after the slice reconstructions with different resolutions, a blurred, discontinuous image is obtained, which will greatly reduce the overall resolution of the scan results and affect the accuracy of the data.
The Endra Nexus 128 is the only complete 3-D photoacoustic imaging system on the market that accurately determines the distribution of probes in tissue, while other photoacoustic systems are based on sliced ​​scanning systems. The complete 3-D photoacoustic imaging system determines that the Nexus128 is superior to other similar products in terms of spatial resolution, sensitivity, animal processing speed, scanning speed and throughput, for the following reasons:
Isotropic resolution (Isotropic resolution): a 3-D system completely have the same resolution in all directions. The slice-based 2-D imaging has a resolution at the center, and the other is a sub-ratio on the outside, which tends to result in uneven resolution. The 3-D image will be blurred and the image will be uneven. phenomenon.
Sensitivity : A complete 3D system can detect photoacoustic signals from the entire volume when a laser pulse occurs.
Flux ( scan speed ): A full 3-D system scans the entire volume in just 3 seconds, while a sliced ​​scan takes 8 minutes or more to complete.
Animal localization: The position of the animal is fixed during the scan in the full 3-D system, and the transducer does not come into contact with the animal. Endra offers two sets of animal trays that speed up animal handling.
Near-infrared small animal photoacoustic imaging can be widely used in the development of new contrast agents (probes), nano-material clinical application analysis, cardiovascular, drug metabolism, early disease diagnosis, tumor efficacy observation, gene expression research, stem cell and immune research, etc. field.
3.1 Optical contrast agent application Â
3.2 Applications in Nanomaterials (New Contrast Agents) Nanomaterials have better light absorption in the near infrared due to their uniform dispersibility and nanometer size, which is the basis of photoacoustic imaging. Endra Nexus 128, because its excitation wavelength is at 680-950 nm, all nanomaterials include carbon nanotubes, gold nanorods, gold nanocages, and gold nanospheres. Both can have corresponding light absorption at this wavelength, which is very beneficial for the research of novel nanoprobes.
Because the Endra Nexus 128 photoacoustic system features non-invasive detection and because it is true 3-D imaging, it is ideal for continuous observation of experimental animals. After the probe is injected into the experimental animal, the experimental animal can be intermittently scanned to obtain dynamic information that the probe is ingested, absorbed, and cleared in the body.
From the interface of software analysis, it can be seen that Nexus 128 can realize all aspects of probe experimental research, including comparing the absorption time of different probes, comparing the absorption time of different regions of the tumor, testing the concentration of probes at different absorption times, and testing the target. The 3-D distribution of the probe inside the tumor, and the like. These applications are critical for probe development and preclinical evaluation.
3.3 Anatomy application    Â
3.4 Oncology application
3.4.1 Tumor Morphology Due to its high resolution, photoacoustic can exert its unique advantages in tumor morphology research. At the same time, since photoacoustic detection is a non-invasive and non-destructive detection method, there is no harm to the experimental materials, so the interpretation of the research results is more scientific and reasonable.
3.4.2 Tumor perfusion Due to the different peripheral and internal structures of the tumor, these two different regions may cause different behaviors for the absorption of contrast agents. Peripheral perfusion of tumors is usually faster, because there are more angiogenesis and metabolism, so the clearance rate is fast, and the curve shows a pattern of rapid rise and fall. On the contrary, due to slow metabolism, the perfusion shows slow rise and fall. Mode, and the overall signal peak is much lower than the tumor peripheral signal. This can be used for tumor state determination. If these two peaks are gradually close in time, it indicates that the tumor is inhibited and progresses toward a good prognosis, and vice versa.
Representative of near-infrared small animal photoacoustic imaging system: Endra Nexus 128
Endra was founded by Enlight Biosciences, a group of seven pharmaceutical companies including Pfizer, Merck, Johnson & Johnson, Abbott, Lilly, Novartis and Astra. The history of Endra's development of photoacoustics dates back to 2001 and has been in existence for nine years. Endra has been conducting applied research in cancer biology and probe development for more than three years.
The Endra Nexus 128 has a dedicated animal preparation station for optical imaging of mice, which can be positioned to blend with photons of sound and ultrasound images.
The Nexus 128 hardware is very easy to use and it is very simple to handle animals, so you can achieve fast animal scanning. Because Endra can choose multiple animal trays for the user, the animal tray can simultaneously perform animal anesthesia and contrast injection while one animal is scanning, thus greatly improving the speed of animal processing.
The Nexus 128 animal tray slot has two optional positions, high and low, corresponding to subcutaneous tumor scanning and whole body imaging scanning, which brings convenience and higher resolution to users, making the experimental results more accurate and reliable.
The Nexus 128 is equipped with an animal processing station with an optical camera that records the position of the animal and then records the location information. In the next image reconstruction, it can be fused with the photoacoustic position, so that the interpretation of the experimental results is more scientific and reasonable.
The Nexus 128 system uses a PC workstation to capture data and another Mac to perform data reconstruction so that capture and reconstruction can be done without interference, and the next step of data capture can be performed simultaneously.
The DICOM format image output by the Nexus 128 can be recognized by all 3-D processing software, so image processing fusion and comparison can be achieved.
Using Nexus 128 software, the position of the animal can be located to achieve fusion with the photoacoustic image, so as to explain the experimental results reasonably. At the same time, 3-D analysis software can be used for specific region selection, specific volume selection, 3-D visual field display, absorbed dose calculation, dynamic probe uptake process calculation, image fusion in different time periods, dose time dynamic distribution, and comparison of different probe absorption processes. , the internal and external dose calculation of tumors and other tasks.
The Endra Nexus 128 offers the following advantages over other products:
Introduction to the principle and application of small animal photoacoustic imaging technology