X

X




X-rays, conventional


Also called: Plain Film




Specimen or type of test:


Radiography



Purpose of the test


An x-ray film provides a radiographic image of the organs or tissues to detect abnormalities such as tumors, perforations, abscesses, infections, foreign bodies, or fractures of the bone.



Basics the nurse needs to know


Conventional radiographs are low-cost procedures that may be used to provide a preliminary image, with low exposure to radiation for the patient. Computed tomography, magnetic resonance imaging, nuclear scan, and ultrasound have replaced many of the previous uses of radiographs, but the conventional radiograph is still a mainstay of imaging of musculoskeletal tissue, particularly in trauma cases (Renner, 2009).


The source of x-ray emissions are photons created in a special vacuum tube in the x-ray machine. The guided x-ray energy waves are focused on the area of tissue to be imaged. They pass through the patient and onto a photographic plate called an x-ray film. Newer technology is replacing the old method of imaging on film. The new filmless images use computerized digital imaging that is seen on a monitor or display screen.


The varying densities and composition of the tissues permit different amounts of photons to pass through and make photographic images. Dense, thick tissue is more radiopaque, resulting in lighter shades of image. For example, bone contains calcium, a mineral that is radiopaque. Thus bone appears almost white against the contrasting shades of gray of soft tissues and muscles that surround the bones. Conversely, air allows the photons to pass through the tissues or organs such as the lungs, without blockage of the photons. Thus the presence of air (as in the lungs) produces images that are very dark or black. The size, shape, and position of the organs or tissues are accurately visualized because of the differences in the densities and composition of the tissues.


Metal objects absorb or block x-ray emissions and will appear white on the film. Before the radiograph is taken, patients must remove all metal objects and jewelry so that the underlying tissue can be visualized. Radiographs are very useful to image a metallic foreign body that is swallowed, aspirated, or has penetrated the body (Figures 105 and 106).


image

Figure 105. Coin in the esophagus. The coin was swallowed and lodged in a narrowed section of the esophagus. The radiograph (lateral view) of the chest shows the metal coin and its location very clearly.


(From Mettler FA: Essentials of radiology, ed 2, Philadelphia, 2005, Saunders.)


image

Figure 106. Foreign body. The lateral view of the ankle shows a construction nail that has passed through the talus bone.


(From Renner JB. (2009) Conventional radiography in musculoskeletal imaging, Radiol Clin N Am 47(3): 357-372.)


The radiopacity of metals is useful for protection against unwanted exposure to radiation. The x-ray emissions cannot pass through lead of particular thickness. The patient and staff members wear a lead protective shield or apron to protect reproductive organs and other radiosensitive tissue. For example, nurses would wear a lead shield in the operating room when radiographs of the patient are taken. Lead is also used to line the walls of the x-ray rooms so that radiation energy cannot pass into the corridors or nearby offices. This protects workers and others from unwanted exposure.


Three-dimensional (3-D) views of the tissue are obtained by filming from the front to the back of the body as well as from the side. In radiology, these views are called anteroposterior and lateral (AP and lateral). Other positions, such as oblique views, may be requested to image a particular section of anatomy that is less visible from a traditional position. All AP x-ray films are viewed as if the patient were facing you. This means that the patient’s left side is on your right side. To prevent confusion and possible error in the interpretation of the film, the technician places the letters R and L on the film to indicate the patient’s right and left sides.




Chest radiograph

This film is obtained routinely for preoperative patients to screen for tuberculosis and other serious pulmonary or cardiac diseases. It also provides a preoperative comparison film for the postoperative patient in whom a pulmonary or cardiac complication develops. The chest radiograph is a basic radiologic procedure to identify broken ribs, a pneumothorax, or suspected pulmonary disorder (Figure 107). The chest radiograph also provides data about the heart, including its size and shape. In congenital and acquired cardiac disease, the enlargement of the heart and its atria or ventricles provides information about the improper function of the cardiac valves, pulmonary or aortic arterial hypertension, and venous pulmonary conditions that affect heart size.


image

Figure 107. Lung cancer. A, The posteroanterior radiographic view of the lung shows an ill-defined mass (arrows). Its shaggy appearance is very suggestive of carcinoma. B, Follow-up with a computed tomography scan on the same patient provides a clear view of the tumor (arrow), its location and relationship to the mediastinal structures, including the pulmonary artery (PA) and aorta (AO).


(From Mettler FA: Essentials of radiology, ed 2, Philadelphia, 2005, Saunders.)

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Feb 18, 2017 | Posted by in NURSING | Comments Off on X

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