Presentation on theme: "Conventional Radiography By Dr. Amr A. Abd-Elghany Mobile x-ray."— Presentation transcript:
Conventional Radiography By Dr. Amr A. Abd-Elghany Mobile x-ray
Introduction X-ray is an imaging technique that has been used since 1895 to show up abnormalities in bones and certain body tissue, such as breast tissue. X-rays are a type of high-energy radiation that is like light waves but higher in energy. An X-ray machine can produce short bursts of X-rays that pass easily through fluids and soft tissues of the body but are blocked by dense tissue such as bone. Contrast X-rays use a substance (called a contrast medium) that makes hollow or fluid-filled structures visible. This means that structures such as the digestive tract, blood vessels or urinary system that do not usually show up on X-ray, can be seen. The substance is injected or swallowed and X-rays cannot pass through it, so the area will appear white on the X- ray.
What are x-rays? No mass No mass No charge No charge Energy Energy What is your observation?
Basic x-ray physics X-rays: a form of electromagnetic energy Travel at the speed of light Electromagnetic spectrum X-rays – Gamma RaysX-rays – Visible lightInfrared light – MicrowavesRadar – Radio waves
Three things can happen X-rays can: – Pass all the way through the body – Be deflected or scattered – Be absorbed Where on this image have x-rays passed through the body to the greatest degree?
X-rays Passing Through Tissue Depends on the energy of the x-ray and the atomic number of the tissue Higher energy x-ray - more likely to pass through Higher atomic number - more likely to absorb the x-ray Diagnosis?
How do x-rays passing through the body create an image? X-rays that pass through the body to the film render the film dark (black) X-rays that are totally blocked do not reach the film and render the film light (white) Air = low atomic # = x-rays get through = image is dark Metal = high atomic # = x-rays blocked = image is light (white)
5 Basic Radiographic Densities Air Fat Soft tissue/fluid Mineral Metal Name these radiographic densities.
History: “I think my dog swallowed a rock” Diagnosis: “Yes, he did.”
What is used for? Check bone fractures and osteoporosis. Check teeth and joints. Examine heart and lungs (chest x-ray). Examine breast tumors (mammogram).
Steps for optimal chest x-ray Accurate patient positioning Tube film distance Full inspiration Adequate penetration (thin patient takes low dose while fat one takes higher dose for good image resolution)
Exposure (technique) factors for film screen imaging Kilovolt (kV)-controls the energy (penetrating power) of the x-ray beam. Milliamperage (mA)-controls the quantity or number of x-rays produced. Exposure time (ms)-controls the duration of the exposure, usually expressed in milliseconds.
General Terms Radiograph: is a film or other base material containing a processed image of an anatomic part of the patient as produced by action of x-rays on an IR. Radiography: the production of radiographs or other forms of radiographic images. Radiograph vs. x-ray film: x-ray film refers the physical piece of material on which a radiographic image is exposed. The term radiograph includes the film and the image. Radiographic images: are representation of patient anatomic structures. They can be obtained as a hard copy or digitally.
Radiographic examination or procedure Positioning of the body part and central ray CR. Selection of the radiation protection measures. Selection of the exposure factors on the control panel. Patient instructions relating to respiration. Processing of the IR.
Positioning Postro-anterior (Chest PA): -The radiation enters the body from the posterior. -Standard position preferred in diagnosis. -The heart is near to the film so there is no magnification of the heart. -Lung divided into four regions: -Apex -Upper lung zone -Middle lung zone -Lower lung zone
Antero posterior chest X-ray In case of emergency patients (Supine AP).
PA versus AP The AP shows magnification of the heart (transverse cardiac diameter not correct) and mediastinum. AP views are less useful and should be reserved for very ill patients who cannot stand erect.
Erect versus supine chest x-ray False impression due to magnified heart and difficulty in breathing (wrong diaphragm position).
Left lateral To detect lesions (is any abnormality in the tissue of an organism) in the left lung. The left side is near from the film.
Adequate penetration Over exposure Over dose under exposure We can not see details
Full inspiration level The diaphragm is at the 10 th rib in the full inspiration level.
Lateral chest x-ray Lower dorsal vertebrae are darker than upper ones due to the presence of shoulder bones (normal). If the upper dorsal vertebrae were dark and lower ones were brighter then we have lesions may be pneumonia. Right lower lobe
Normal PA film without rotation
Radiographic Analysis Any structure, normal or pathologic, should be analyzed for:Any structure, normal or pathologic, should be analyzed for: Size Shape and contour Position Density (You must know the 5 basic densities)
Radiographic signs Silhouette sign: opacity near the heart so you can not detect the heart boarder easily. Notes from the radiographs: opacity frontal and heart frontal so lesion is frontal.