Key Points
Learn what radiography is and the types of equipment that’s involved
Occasionally someone will ask us “What is radiography?” Today we will be taking a closer look at what radiography is and the types of equipment that’s involved.
What is Radiography?
Radiography is the art and science of using radiation to provide images of the tissues, organs, bones, and vessels that comprise the human body.
Radiographic Uses
Radiography is used in many types of examinations and procedures. Some examples include:
- Dental examination
- Verification of correct placement of surgical markers prior to invasive procedures
- Mammography
- Orthopedic evaluations
- Spot film or static recording during fluoroscopy
- Chiropractic examinations
What is Radiographic Technology?
Radiography is an important component in the field of patient care that requires excellent attention to detail and interpersonal communication to take the perfect x-ray.
Because radiology exposure can be potentially harmful, an x-ray technician must take necessary precautions for everyone’s safety during procedures. Radiography technicians must also know how to properly position patients for testing and accurately adjust highly advanced machinery.
The Technology Used in X-Rays
Image quality
Image quality will depend on resolution and density. Resolution is the ability of an image to show closely spaced structure in the object as separate entities in the image while density is the blackening power of the image. The sharpness of an x-ray image is strongly determined by the size of the x-ray source. An x-ray tech must know how to calculate the machinery in order to get a quality image.
X-ray generator
In medicine and dentistry, projectional radiography and computed tomography images generally use X-rays created by X-ray generators, which generate X-rays from X-ray tubes. The resultant images from the radiograph (X-ray generator/machine) or CT scanner are correctly referred to as “radiograms”/”roentgenograms” and “tomograms” respectively.
Grid
A Bucky-Potter grid may be placed between the patient and the detector to reduce the number of scattered x-rays that reach the detector. This improves the contrast resolution of the image but also increases radiation exposure for the patient.
Detectors
Detectors can be divided into two major categories: imaging detectors (such as photographic plates and x-ray film, now mostly replaced by various digitizing devices like image plates or flat panel detectors) and dose measurement devices (such as ionization chambers, Geiger counters, and dosimeters used to measure the local radiation exposure and dose for verifying that radiation protection equipment and procedures are effective on an ongoing basis).
Side markers
A radiopaque anatomical side marker is added to each image. For example, if the patient has their right hand x-rayed, the radiographer includes a radiopaque “R” marker within the field of the x-ray beam as an indicator of which hand has been imaged.
X-ray image intensifier
As an alternative to x-ray detectors, image intensifiers are analog devices that readily convert the acquired x-ray image into one visible on a video screen. The image from the output can then be recorded via a camera and displayed.
Array detectors
Digital devices known as array detectors are becoming more common in fluoroscopy. These devices are made of discrete pixelated detectors known as thin-film transistors (TFT).