Radiography and MRI Principles

• Radiography is a key diagnostic imaging method that uses X-rays to see inside the body
• Relies on how different tissues absorb X-rays
• Denser tissues (like bone) absorb more X-rays and look whiter on the image, while less dense tissues appear darker
• Standard X-ray images are 2D views of 3D structures
• Barium or iodine contrast agents can be used to improve the visibility of specific organs or tissues

X-ray Imaging Techniques

• Several X-ray imaging exist, including conventional, fluoroscopy, and digital radiography
• Conventional radiography captures images on X-ray film
• Fluoroscopy provides real-time imaging to observe internal movement, used during surgery or injections
• Digital radiography uses digital sensors instead of film, allowing for quick image review and manipulation

MRI Principles

• MRI (Magnetic Resonance Imaging) creates detailed organ and tissue images using strong magnetic fields and radio waves
• MRI does not use ionizing radiation
• A large magnet aligns hydrogen atom magnetic moments in the body
• Radio waves disrupt this alignment temporarily
• As atoms return to their original state, they emit detectable signals and are processed to make cross-sectional images that can be combined into 3D images
• MRI excels at imaging soft tissues like the brain, spinal cord, and joints
• Gadolinium contrast agents can improve the visibility of blood vessels and tissues

CT Scan Technology

• CT (Computed Tomography) combines X-ray and computer processing to create cross-sectional body images
• The patient lies on a table that slides through a donut-shaped X-ray machine
• The X-ray tube rotates, taking images from multiple angles
• A computer uses these images to create detailed cross-sectional views
• CT scans offer more detail than standard X-rays, especially for soft tissues and blood vessels
• Contrast agents improve the visibility of specific structures
• CT scans diagnose infections, injuries, and tumors

Radiation Safety Protocols

• Radiation safety is critical in radiography and CT scanning to minimize radiation exposure
• The ALARA (As Low As Reasonably Achievable) principle guides radiation safety; all efforts should be made to lower radiation exposure
• Shielding (lead aprons, thyroid shields) protects patients and staff
• Collimation narrows the X-ray beam to the area of interest, reducing radiation to other areas
• Exposure parameters (radiation amount, exposure time) are carefully controlled to minimize radiation while maintaining image quality
• Regular monitoring ensures protocols are followed
• Staff training on radiation safety is essential

Diagnostic Imaging Applications

• Diagnostic imaging techniques are used to diagnose a wide range of medical conditions
• Radiography diagnoses fractures, pneumonia, and bowel obstructions
• Fluoroscopy guides injections and biopsies and evaluates gastrointestinal function
• MRI diagnoses brain tumors, spinal cord injuries, and joint problems
• CT scans diagnose infections, injuries, and tumors in the chest, abdomen, and pelvis
• Ultrasound evaluates pregnancies, diagnoses gallstones, and assesses blood flow
• Nuclear medicine imaging diagnoses heart disease, cancer, and thyroid disorders
• Diagnostic imaging guides treatment decisions
• The choice of imaging depends on the clinical question being asked