permits scanography of objects any length. When the rule is placed on the films, it
should be aligned so that it is parallel with the long axis of the object under
consideration. Cone coverage must be sufficient to demonstrate both the point on the
object and the corresponding portion of the calibrated rule. Measurement is
accomplished by aligning the point on the object with the known markings on the
calibrated rule. Either non-Bucky or Bucky technique may be used. The calibrated rule
should be placed on the tabletop. In this way, both exposures can be accomplished on
a single film.
d. Slit-Scanography. This method is useful in that it produces an image that
shows the object in its entire length. Any part or portion of the object may be measured.
In slit-scanography. A narrow slit is used beneath the x-ray tube or the lip surface of a
cone in such a way that a line or sheet of x-rays is used. As the x-ray tube moves over
the object from one end to the other, the rays of the central beam pass through the part
at the same angle. A sheet of lead, about 3/16 inch in thickness and a proper size to fit
into the slot under the tube where filters are generally inserted, may be used. The width
of the slit-should be about 1/4 mm. The length of the cut in this piece will depend on the
extent of lateral coverage desired or necessary in relation to the long axis of the object.
For detail information on this method and other methods of orthoradiography, the x-ray
specialist should consult standard texts.
Section V. THE SKELETAL SYSTEM
One of the most important, yet frequently overlooked, aspects of radiography is
the dealing with the skeleton as a system rather than as a unit made up of individual
components. For example, bone radiography of the upper extremity is usually thought
of in terms of a hand, a wrist, a forearm, a humerus, etc., rather than the entire
extremity combined. Radiographs of these individual bone elements are usually made
for the purpose of diagnosis as a direct result of trauma. Do not forget that the skeleton
is often x-rayed as an indirect result of trauma or as the result of some impairment of
the normal function of the skeletal system in the process of one growth. It is with
broader viewpoint that radiography of the skeletal system is primarily concerned.
Radiography of the skeletal system may be defined as the interpretation of the
condition and relationship of the bony structures by means of radiographic visualization.