Principles of Radiography PDF

Principles of Radiography Mohamed Almedfa M.D., M.Sc. Internal Medicine Department Arabian Gulf University Introduction X-Rays were discovered by the German physicist Wilhelm Roentgen in 1895 He was experimenting on cathode ray tubes and noticed a screen he set up fluoresce (light up) He...

Principles of Radiography Mohamed Almedfa M.D., M.Sc. Internal Medicine Department Arabian Gulf University Introduction X-Rays were discovered by the German physicist Wilhelm Roentgen in 1895 He was experimenting on cathode ray tubes and noticed a screen he set up fluoresce (light up) He concluded that there are invisible rays that caused the screen to light up and named them “X-rays”, with X being the mathematical symbol “x” for something unknown Loading… Cathode Ray Tube Loading… X-Rays Part of the electromagnetic spectrum High energy (High frequency and short wavelength) Type of ionizing radiation (can remove electrons from atoms or molecules) Ionizing radiation is detrimental to human tissues (can break chemical bonds and damage or kill cells) Digital Radiography Photographic films (Early x-ray machines) were replaced by photosensitive cassettes or plates The image is processed by an electronic reader and then stored in a digital format A system was developed to archive images, communicate them to others, and store them on servers The system is called PACS (Picture Archiving and Communications System) vitrasound , c+ X-ray Fate of Radiation During an Imaging Procedure Passing X-rays and Image Generation Image generation depends on the interaction between X-rays and body tissues Generally, tissues with a smaller atomic number allow x-rays to pass through to the film -> appear as black or lucent Tissues with a larger atomic number block x-rays from passing to the film -> appear as white or dense Tissues in the middle allow for partial passage of x-rays -> appear in various shades of gray small atomic number= black atomic number = white large middle grey =  Anterior to posterior Loading… black Iuscent : Five Basic Densities of a Conventional Radiograph we can see all those M Air black attackest Fat gray (whitest) metal Fluid/Soft tissue eg organ. , muscle I Bone Metal In foreign body or tubes in a sick patient (grey at X-Ray Projections Antero-posterior (AP): central ray passes, perpendicular to the coronal plane, from anterior to posterior Postero-anterior (PA): central ray passes, perpendicular to the coronal plane, from posterior to anterior Lateral: central ray, perpendicular to the sagittal plane and parallel to the coronal plane, passes from one side of body to the other Oblique: central ray passes through the body/body part through a plane which is at an angle to the transverse plane/coronal plane Axial: central ray passes through (or parallel) to the long axis of the body  Imaging of the Musculoskeletal System for compartment syndrome first line is X-ray investigation Plain radiographs are the first modality of choice in imaging the Musculoskeletal system. ? Swny Advantages: ↳ Inexpensive Fast Readily available Very reliable in detecting bony abnormalities (fractures, tumors) If suspecting a soft tissue injury (Cartilage, ligaments, tendons), MRI is superior Swe can't see soft tissue in * ray : mui is better Rule of Two’s to make sure Two views (AP and Lateral) Two joints (Include the joint above) Two sides (Compare with contralateral side) Two occasions (Compare with old/previous imaging study) Two opinions (Ask colleague if not sure) Two investigations (Consider whether US, CT, or MRI would help in diagnosis)  Done Stay L fat Normal long bones in (a) child and (b) adult. Increase in length ↓ takes place at the cartilaginous epiphyseal plate. In the growing soft Issue air child, calcification of cartilage occurs at the interface between the radiolucent growing cartilage and the bone to give the zone of H denst ↓ provisional calcification, which is seen as a dense white line forming the ends of the shaft and surrounding the bony epiphyses. This calcified cartilage is converted to bone. (If there is temporary cessation of growth then the zone of provisional calcification may persist as a thin white line, known as a ‘growth line’, extending across the shaft of the bone.) As the child grows older the epiphyseal plate becomes thinner until, eventually, there is bony fusion of the epiphysis with the shaft. Child adult  fat h muscle L dir fat Y L muscle h bore external metal Y L air sat Muscle Done swaen M metal