Modern Microscopy Lecture 14 PDF

modern microscopy - lecture 14 Created @December 9, 2024 8:33 PM Class its whats the inside that counts Introduction X-rays are primarily used to examine bones and dense tissues. Limitations of X-rays...

modern microscopy - lecture 14 Created @December 9, 2024 8:33 PM Class its whats the inside that counts Introduction X-rays are primarily used to examine bones and dense tissues. Limitations of X-rays: Ineffective for soft tissues. Cannot capture live processes. This lecture explores alternative imaging techniques for whole-body imaging and live processes. Main techniques discussed: MRI, angiography, ultrasound, bioluminescence, and fMRI. Magnetic Resonance Imaging (MRI) Overview MRI stands for Magnetic Resonance Imaging. Utilizes powerful magnets and radio waves to produce high-resolution images of the body. Particularly effective for soft tissue visualization due to high water content (protons) in tissues. How It Works 1. Powerful magnets align proton nuclei in tissues along a magnetic field. 2. Radio waves are used to shift protons, causing them to resonate. 3. As protons return to alignment, they emit energy detected by the scanner. modern microscopy - lecture 14 1  4. Produces detailed images in slices, which can be combined for 3D visualization. Advantages High-resolution imaging, especially for soft tissues. Non-invasive and safe for most patients. Limitations Expensive equipment (multi-million pounds). Requires the patient to stay still during the scan. Fun Fact Magnets in MRI machines are extremely powerful. Accidents include heavy metal objects being pulled into scanners. Functional MRI (fMRI) An extension of MRI technology. Detects metabolic activity by measuring oxygen usage in tissues. Useful for mapping brain activity in real-time, often while providing stimuli to the subject. Commonly used in neuroscience to study brain functions such as fear processing (e.g., amygdala activity). Ultrasound Imaging Overview Uses ultrasonic sound waves to create images of internal body structures. Widely used for monitoring fetal development, diagnosing organ issues, and visualizing heart function (echocardiography). How It Works modern microscopy - lecture 14 2  1. High-frequency sound waves are transmitted into the body. 2. Waves bounce back when they hit structures, and the time taken to return is measured. 3. Creates a 2D or 3D image of the structure. Doppler Ultrasound Measures movement, especially blood flow, using the Doppler effect. Useful for detecting blockages or irregular blood flow in arteries and veins. Applications Fetal monitoring. Heart function analysis (e.g., echocardiography). Blood flow assessment in real-time. Bioluminescence Imaging Overview Primarily a research tool. Involves the use of fluorescent proteins or enzymes (e.g., green fluorescent protein, luciferase). How It Works 1. Transgenic animals are engineered to express fluorescent proteins in specific tissues. 2. Proteins emit light when exposed to UV or during specific chemical reactions. 3. Allows researchers to study gene expression and cellular processes. Applications Understanding gene regulation. Studying tumor growth in animal models. modern microscopy - lecture 14 3  Limitations Not suitable for clinical use as it involves genetic modification. Angiography Overview Real-time imaging of blood vessels using X-rays and contrast dyes. Commonly used for visualizing coronary arteries, brain vessels, and kidney circulation. How It Works 1. A catheter is inserted into a large blood vessel (e.g., groin or armpit). 2. Contrast dye is injected to make blood vessels visible on X-rays. 3. Live X-ray images are recorded to observe blood flow. Applications Detecting blockages (e.g., thrombosis). Guiding stent placement to open clogged arteries. Monitoring heart muscle contractions during a heart attack. Conclusion Advanced imaging techniques have revolutionized diagnostics and research. Each method has unique strengths, applications, and limitations. Continued innovation, like fast-field MRI and enhanced ultrasound, promises even greater capabilities in the future. modern microscopy - lecture 14 4