Preliminary Steps in Radiography
The Radiographer and Professional Standards
Radiologic technology is a health care profession encompassing all diagnostic imaging technologists and radiation therapists. A radiographer is a specific radiologic technologist who administers ionizing radiation to perform radiographic procedures. This role requires a combination of technical skills and a robust knowledge base in the areas of physics, anatomy, physiology, and pathology.
Professional guidelines are established by the American Society of Radiologic Technologists (ASRT). The Radiography Practice Standards, which are written and maintained by the ASRT, define the practice of radiography and describe the necessary education and certification. These standards include the Radiographer Scope of Practice, Clinical Performance Standards, Quality Performance Standards, and Professional Performance Standards. The most current version of these documents is available on the ASRT website (ASRT.org).
Ethics in Radiography
Ethics in the context of radiography is defined as the science of appropriate conduct toward others and the professional's moral responsibility. The American Registry of Radiologic Technologists (ARRT) created and maintains the Standards of Ethics for Radiologic Technologists. This document is comprised of two components:
Code of Ethics: Consists of 10 statements that serve as a guide for professional behavior.
Rules of Ethics: Consists of 22 specific rules.
Full descriptions and lists of these ethical standards are available at ARRT.org.
Advanced Clinical Practice
For radiographers providing advanced imaging services, the titles Radiologist Assistant (RA) and Radiology Practitioner Assistant (RPA) are used. To practice at this level, individuals must meet specific requirements:
Possess ARRT radiography certification.
Complete additional education.
Gain clinical experience under the supervision of a radiologist preceptor.
Pass an advanced-level certification examination before using the RA or RPA title.
Care of the Examination Room and Infection Control
The radiographer is responsible for the upkeep of the examination room to minimize infection transmission and foster patient confidence. This includes keeping the room clean and maintaining a stock of essential items such as linens, contrast media, and ancillary equipment.
Infection control is guided by directives from the CDC, with standard precautions serving as the foundation. These include:
Performing diligent hand hygiene.
Using Personal Protective Equipment (PPE) when exposure to infectious material is possible.
Following respiratory hygiene and cough etiquette.
Ensuring appropriate patient placement.
Properly handling, cleaning, and disinfecting patient care equipment and environmental surfaces.
Careful handling of textiles and laundry.
Following safe injection practices, including wearing a surgical mask when performing lumbar punctures.
Ensuring health care worker safety, particularly in the handling of needles and sharps.
Transmission-based precautions are implemented in addition to standard precautions for patients with known or suspected infections.
Hand Hygiene Protocols
Hand hygiene is recognized as the easiest and most convenient method of preventing the spread of microorganisms. Radiographers must wash their hands before and after working with every patient. Specific instances requiring hand washing include:
After examining patients with known communicable diseases.
After contact with blood or body fluids.
Before starting invasive procedures.
Before touching patients who are at high risk for infection.
Basic Patient Care and History
The radiographer is responsible for the patient's care throughout the imaging procedure. A critical task is obtaining the patient's clinical history. This ensures the correct procedure was ordered and allows the technologist to observe conditions or abnormalities that should be relayed to the radiologist.
Motion Control and Image Quality
Motion during imaging ruins image quality by creating a fuzzy appearance at the edges of bones. There are three types of motion:
Involuntary Motion: Caused by heartbeats, chills, peristalsis, tremors, spasms, or pain. The primary means of control is using a short exposure time.
Voluntary Motion: Caused by nervousness, discomfort, excitability, mental illness, fear, age, or breathing. Control methods include giving clear instructions, providing patient comfort, adjusting support devices, applying immobilization, and decreasing exposure time.
Equipment Motion: Movement of the imaging hardware itself.
Image Receptors (IR)
An image receptor (IR) is the device that receives x-ray beam energy and forms the image of the body part. There are four primary types:
Cassette with film.
Photostimulable storage phosphor image plate (PSP IP).
Solid-state digital detectors (including portable, tethered, and wireless digital radiography).
Fluoroscopic image receptors (including digital fluoroscopy flat-panel detectors).
Accessory Equipment and Procedural Steps
Accessory equipment includes positioning aids, grids, and compensating filters. To improve efficiency, ensure safety, and minimize radiation exposure, radiographers follow a set of common steps for each procedure. While the order may vary based on anatomy, patient condition, equipment, or protocol, these steps are standardized as seen in Table 1-3.
Exposure Technique and Technique Charts
Every room and mobile unit must have technique charts specifying the projections performed and the necessary exposure factors. Primary factors to establish correct foundation technique include:
Milliampere-seconds (mAs).
Kilovolt (peak) (kVp).
Automatic exposure controls (AECs).
Source-to-image receptor distance (SID).
Relative patient or part thickness.
Grid usage.
Digital exposure indicators or value estimates (CR/DR).
IR or collimated field dimensions.
Electrical supply characteristics such as phase and frequency.
Gonad Shielding and IR Placement
Gonad shielding should be used when the gonads lie within or close to () the primary x-ray field, if it does not compromise the clinical objective, and if the patient has reasonable reproductive potential.
Image receptors are placed in one of three general positions relative to the long axis of the body:
Lengthwise (most common).
Crosswise.
Diagonal.
Central Ray (CR) Direction
The central ray is the principal beam of rays and is typically centered to the IR. The general goal is for the CR to be perpendicular to the part and the IR to minimize distortion. Angling the CR through the part of interest is done to:
Avoid superimposition of structures.
"Straighten out" curved structures.
Align the CR through an angled joint space.
Avoid distortion of an angled structure.
Source-to-Image Receptor Distance (SID)
SID is the distance from the anode inside the x-ray tube (the source) to the IR. It is a critical technical component affecting magnification, spatial resolution, and patient dose. A longer SID reduces magnification and increases spatial resolution. Standardized distances include:
(): Traditionally used for most exams; recommended minimum by Merrill’s Atlas if a specific SID is not mentioned.
(): A recent increase adopted by many facilities.
(): Used to reduce magnification in examinations with increased object-to-image receptor distance (OID).
Collimation and Shuttering
Collimation is the restriction of the radiation field to the anatomy of interest. It minimizes patient exposure and reduces scatter radiation (improving contrast resolution). It is a violation of the ARRT Code of Ethics and ASRT Practice Standards to collimate larger than the required field size.
Shuttering is a digital software feature used for image display aesthetics, providing a black background around the field. It is not a substitute for collimation. Using a larger exposure field and then "cropping-in" or shuttering creates legal and ethical liability, as the patient is overexposed and potential diagnostic information may be lost.
Anatomic Markers and Radiograph Evaluation
Medicolegal requirements mandate the use of appropriate Left (L) or Right (R) markers on every radiograph. Markers should:
Never obscure anatomy.
Be placed in the exposure field at the edge of the collimation border.
Be placed outside of lead shielding.
Be used with both CR and DR imaging (post-acquisition digital annotation is not recommended).
A radiograph is the image recorded by exposing an IR to x-rays. Radiographers evaluate images for feature acceptability, safety practices, and diagnostic objectives. Evaluation requires knowledge of anatomy, image geometry, display characteristics, and pathology.
Image Display and Identification
Radiographs are usually viewed in the anatomic position, with exceptions for hands, wrists, feet, and toes (which are viewed from the perspective of the tube with distal ends toward the ceiling). Required identification on an image includes:
Date of the procedure.
Patient's name or ID number.
Right or left side marker.
Institution identity.
Working with Obese Patients
Obesity is defined as a BMI of to , while morbid obesity is a BMI of . Communication is crucial; radiographers should use empathic communication, avoid mentioning weight, and explain the personnel needed for safe transfers. Safety measures include checking the table's weight capacity and ensuring adequate staff assist with movement.
Palpating landmarks is difficult in morbidly obese patients. The jugular notch is used as a reference point to locate the pubic symphysis based on height:
Height < : from jugular notch.
Height to : from jugular notch.
Height > : from jugular notch.
Questions & Discussion
Q: What is the easiest method to control the spread of pathogens? A: Hand hygiene.
Q: Which of the following is NOT an example of involuntary motion? A: Breathing (Breathing is considered voluntary, whereas peristalsis, heartbeat, and chills are involuntary).
Q: How do radiographers help reduce the risk of imaging involuntary motion? A: Use the shortest possible exposure time.
Q: Which of the following is NOT required ID on a radiographic image? A: Referring physician's name (Side markers, patient name/ID, and facility name are required).
Q: What factor is NOT required on a technique chart? A: Pathology type (kVp, AEC, and Grid must be included).
Q: What guideline is used to locate the pubic symphysis on an obese patient who is approximately 5 feet, 5 inches tall? A: from the jugular notch.