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Infection Control in Radiology: Standard and Transmission-Based Precautions

Why Infection Control Matters for Rad Techs

Radiologic technologists often move among patients, exam rooms, and shared imaging equipment throughout a shift. Patients may be colonized or infected without obvious signs, and portable equipment may travel between care areas. This workflow creates opportunities for transmission unless hand hygiene, appropriate barriers, and equipment reprocessing are built into each exam.

Healthcare-associated infections affect approximately 1 in 31 hospitalized patients on any given day, according to the CDC. Many of these infections are preventable through proper adherence to infection control practices. For rad techs, this isn't just about protecting yourself — it's about protecting every patient who follows, your colleagues, and the vulnerable immunocompromised patients who pass through your department.

The ARRT exam includes infection control and safety questions across multiple content categories, particularly in Patient Care (domain 1 of the ARRT Radiography exam). Understanding the hierarchy of infection control — from standard precautions to transmission-based precautions to sterilization — is essential for both clinical practice and exam success.

ARRT Exam Spotlight

ARRT content specifications include infection-control topics such as Standard Precautions, transmission-based precautions, medical asepsis, safe handling of equipment, and disposal of contaminated items. The number and wording of questions can change; use the current ARRT content specifications rather than relying on a promised question count.

The Chain of Infection: Understanding Transmission

To effectively prevent infection, you must first understand how infections spread. The CDC describes the chain of infection, a six-link model showing what must be present for an infection to occur. Break any single link, and transmission is prevented:

1

Infectious Agent

The pathogen (bacterium, virus, fungus, prion). Examples: Staphylococcus aureus, influenza virus, Clostridioides difficile.

2

Reservoir

Where the pathogen lives and multiplies. Human reservoirs (patients, staff), environmental surfaces, equipment, or water sources.

3

Portal of Exit

How the pathogen leaves the reservoir. Respiratory droplets, blood, wound drainage, feces, urine.

4

Mode of Transmission

How the pathogen travels. Contact (direct/indirect), droplet, airborne, vector-borne, or vehicle-borne.

5

Portal of Entry

How the pathogen enters the new host. Mucous membranes, respiratory tract, broken skin, percutaneous (needlestick).

6

Susceptible Host

An individual at risk. Immunocompromised patients, the elderly, neonates, or anyone with breached skin or mucous membranes.

Why this matters to you: Every time you walk into an exam room, you are potentially a mode of transmission. Your hands, your uniform, and your equipment can all carry pathogens from one patient to the next. The goal of infection control is to break the chain at the point you can control — typically the mode of transmission link, through hand hygiene, barrier precautions (PPE), and equipment disinfection.

Standard Precautions: The Foundation

Standard precautions are the minimum infection prevention practices that apply to all patient care, regardless of suspected or confirmed infection status. They were developed by the CDC and are the cornerstone of healthcare infection control. Every rad tech must apply standard precautions during every patient interaction, every time.

Core Elements of Standard Precautions

1. Hand Hygiene — CDC indications closely parallel the World Health Organization's “Five Moments” framework (the named Five Moments are WHO terminology). Clean hands:

Use soap and water when hands are visibly soiled; otherwise CDC prefers alcohol-based hand sanitizer in most clinical situations. Follow the product's directions and rub until dry. During care of patients with C. difficile, gloves and environmental cleaning are central; CDC continues to prefer alcohol-based hand sanitizer for routine hand hygiene unless hands are visibly soiled, while encouraging soap and water as an additional precaution during outbreaks. For suspected or confirmed norovirus, CDC recommends soap and water after care or contact. Local outbreak policy may be more stringent.

2. Use of Personal Protective Equipment (PPE) — Select PPE from the anticipated exposure and posted precautions. One CDC sequence is gown → mask or respirator → goggles or face shield → gloves. CDC illustrates more than one safe removal method: gloves → eye protection → gown → mask/respirator, or gown and gloves together followed by eye protection and mask/respirator. Do not treat doffing as simply “reverse donning.” Avoid touching contaminated surfaces, remove a respirator only after leaving an airborne-infection room and closing the door, and perform hand hygiene immediately after all PPE is removed (and sooner if hands become contaminated).

3. Respiratory Hygiene / Cough Etiquette — All patients and visitors should be instructed to cover their mouth and nose with a tissue (or their elbow) when coughing or sneezing. Posted signs at radiology department entrances should instruct symptomatic patients to wear a surgical mask and notify staff immediately.

4. Safe Injection and IV Practices — Prepare contrast and medications in a clean area using aseptic technique. Use a new sterile needle and a new sterile syringe for every patient and every access; never enter a vial, bag, bottle, or injector reservoir with a used syringe or needle. Scrub needleless connectors with the facility-approved antiseptic for the specified time and allow them to dry before access. Prefer single-dose containers and dedicate them to one patient. Multi-dose vials, if used, must be handled and dated under CDC and facility policy and kept out of the immediate patient-care area. Injector syringes, tubing, valves, and transfer sets may be reused only when the exact FDA-cleared system and manufacturer instructions explicitly permit it; otherwise they are single-patient items.

5. Sharps and Occupational Exposure — Activate engineered safety features and discard sharps immediately in closable, puncture-resistant, leak-resistant, labeled containers located near use. OSHA prohibits bending, breaking, or recapping contaminated needles except when no feasible alternative exists or a specific procedure requires it; then use a mechanical device or one-handed scoop. After a needlestick, cut, or splash to eyes, nose, mouth, or non-intact skin, wash skin with soap and water or flush mucosa with water, report immediately, and obtain urgent confidential medical evaluation. OSHA requires prompt, no-cost post-exposure evaluation and follow-up; HIV post-exposure prophylaxis is time-sensitive. Do not squeeze the wound or use caustic agents.

6. Environmental Cleaning and Disinfection — Reprocess reusable patient-care equipment before another patient uses it. Clean and disinfect environmental surfaces when soiled and on the facility's risk-based schedule, with higher frequency for high-touch surfaces. Always clean visible soil first unless the product label permits a one-step process. Use an EPA-registered product with the needed organism claim and keep the surface visibly wet for the full label contact time; also follow the imaging-device manufacturer's instructions for use (IFU). If the two instructions conflict, stop and escalate rather than inventing a dilution or substituting a chemical.

Clinical Tip: The X-Ray Tube as a Fomite

Tube and collimator handles, detectors, exposure switches, positioning aids, and controls can become contaminated. Reprocess items that contact the patient or contaminated hands before reuse; include other high-touch surfaces according to the facility's written schedule. Use only products and methods compatible with each device's IFU, and observe the disinfectant label's wet contact time. Remove porous or damaged positioning aids from service if they cannot be adequately cleaned.

Transmission-Based Precautions: Going Beyond Standard

When a patient is known or suspected to have an infection that requires additional barriers, transmission-based precautions are added on top of standard precautions. The CDC defines three categories of transmission-based precautions, each with specific PPE and room requirements.

Precaution TypePathogens CoveredRequired PPERoom Requirements
ContactC. difficile, norovirus, scabies; selected draining wounds and multidrug-resistant organisms according to risk and facility policyGown and gloves on room entry; add face/eye protection for anticipated splash or spray.Single-patient room when available; dedicate disposable or reusable noncritical equipment when practical, or clean and disinfect before reuse.
DropletSeasonal influenza, meningococcal disease, pertussis, mumps, rubella (examples; consult CDC Appendix A)Medical mask on entry; add other PPE under Standard Precautions for anticipated exposure.Single-patient room when available; if not, follow facility cohorting and separation rules. Patient masks for medically necessary transport.
AirborneInfectious pulmonary/laryngeal TB and measles; varicella and disseminated zoster need Airborne + ContactFit-tested NIOSH-approved N95 or higher-level respirator. Add gown/gloves for Contact Precautions or anticipated exposure.AIIR with door closed when available. Use an approved alternative plan if no AIIR is available; restrict susceptible personnel for measles/varicella when immune staff are available.

Contact Precautions in Detail

Contact precautions are used for patients with infections spread by direct contact (touching the patient) or indirect contact (touching contaminated surfaces or equipment). For radiology, this means:

Droplet Precautions in Radiology

Droplet Precautions address respiratory pathogens transmitted mainly by droplets generated during coughing, sneezing, or talking. Particle behavior is a continuum, so fixed “greater than 5 microns” and “falls within 3–6 feet” rules are oversimplifications. Use the diagnosis-specific CDC recommendation and current facility policy. Key considerations:

SARS-CoV-2 Is Not a “Surgical Mask Only” Example

CDC's healthcare guidance for suspected or confirmed SARS-CoV-2 calls for a fit-tested NIOSH-approved N95 or higher-level respirator, eye protection, gown, and gloves, with a single-person room and AIIR for aerosol-generating procedures. Follow current respiratory-virus guidance and facility policy rather than placing COVID-19 into a simplified Droplet-only box.

Airborne Precautions: The Highest Level

Airborne Precautions are used for infectious agents that can remain infectious over distance when suspended in air, including infectious pulmonary or laryngeal TB and measles. Varicella and disseminated herpes zoster require both Airborne and Contact Precautions. Do not rely on a rigid particle-size cutoff.

ARRT Exam Classic: Airborne vs Droplet

Airborne Precautions require a fit-tested NIOSH-approved N95 or higher-level respirator; Droplet Precautions require a medical mask on entry. “MTV” can cue measles, TB, and varicella, but it is not a complete policy: varicella also needs Contact Precautions, and COVID-19 healthcare PPE includes a respirator, eye protection, gown, and gloves.

Key considerations for airborne precautions in radiology:

Apply pathogen-specific rules as well. For measles, CDC states that an AIIR should remain vacant for up to two hours after the patient leaves because virus can remain infectious in air for that period; staff use respiratory protection regardless of presumptive immunity, and susceptible personnel should not enter when immune personnel are available. For varicella or disseminated zoster, maintain Airborne plus Contact Precautions, cover lesions when feasible, and preferentially assign personnel with evidence of immunity. Facility infection prevention determines clearance and reuse of the room.

Equipment Disinfection: Spaulding Classification

Not all medical equipment requires the same level of disinfection. The Spaulding classification system categorizes equipment by the risk of infection associated with its use, guiding the appropriate disinfection or sterilization method:

ClassificationDefinitionRadiology ExamplesRequired Processing
CriticalEnters sterile tissue or the vascular systemReusable surgical instruments; reusable biopsy guides that enter sterile tissue. Needles, angiographic catheters, and many contrast-fluid-path components are supplied sterile for single use.Sterilize reusable, heat-stable items with steam when possible; otherwise use a compatible validated low-temperature method. Do not reprocess a single-use device unless legally permitted through an FDA-regulated reprocessor.
SemicriticalContacts mucous membranes or non-intact skinEndocavitary ultrasound probes and reusable devices that contact non-intact skinThorough cleaning followed by high-level disinfection, using an FDA-cleared product/system and the probe and reprocessor IFUs. A probe cover does not replace reprocessing.
NoncriticalContacts intact skin onlyExternal ultrasound probes, DR detectors or positioning aids that touch intact skin, blood-pressure cuffs, lead apronsClean and apply low-level disinfection with an EPA-registered product compatible with the device. Use an intermediate-level/tuberculocidal claim when indicated by blood contamination or facility policy.

Clinical Tip: CR Cassettes and DR Detectors

Classify a detector or cassette by how it is used and whether a barrier remained intact. Clean it and use only the disinfectants, concentrations, application methods, and frequencies allowed by the manufacturer's IFU. Do not assume that 70% alcohol, quaternary-ammonium, or bleach products are universally safe or effective. A disposable barrier reduces contamination but does not replace inspection, cleaning, and disinfection when the barrier is torn, visibly contaminated, or the IFU requires reprocessing.

Imaging the Isolation Patient: Step-by-Step Workflow

Portable workflows must match the posted isolation category, equipment IFUs, and the facility's written infection-prevention plan. The following is a planning framework—not a universal room-entry or clean/dirty-zone protocol:

Step 1: Preparation (Before Entering the Room)

Step 2: During the Exam

Step 3: After the Exam (in the Room)

Step 4: Post-Exam Processing

Special Considerations in Radiology

MRI and Ultrasound Probe Disinfection

Each modality has unique compatibility constraints. In MRI, bring only MR Safe or MR Conditional supplies into the controlled area under their conditions of use; separately, confirm chemical compatibility with the scanner, coils, table pads, and bore IFUs. Clean and disinfect patient-contact surfaces before reuse and other high-touch surfaces on the facility schedule. In ultrasound, clean every probe after use. Probes contacting intact skin require low-level disinfection; probes contacting mucosa or non-intact skin require high-level disinfection even when a cover was used. A probe entering sterile tissue should be sterilized when possible; if sterilization is not possible, AIUM describes high-level disinfection plus a sterile single-use cover, subject to the probe IFU and facility policy.

Use sterile, single-use gel for procedures involving a sterile site or non-intact skin, for invasive procedures, and for neonates or severely immunocompromised patients when indicated by policy. Nonsterile gel may be used for low-risk examinations on intact skin; if refillable or multiuse containers are permitted, handle them exactly as infection-prevention policy specifies—never “top off” bottles. Covers can fail and never substitute for cleaning and the required level of disinfection.

CT Isolation Scanning

For medically necessary transport, contain infectious drainage, place a mask on a patient on Droplet or Airborne Precautions if tolerated, cover clean linens, notify the receiving department, and maintain the indicated precautions. Keep clean control areas from becoming contaminated: remove PPE and clean hands before touching the console unless the facility has a defined contaminated-console workflow. Anyone entering the scan room follows the posted precautions. Reprocess the table, coils/holders, positioning aids, and other contaminated patient-care equipment before reuse; clean environmental high-touch surfaces according to policy and product/device IFUs.

Linen and Waste

Handle used linen with minimal agitation, do not sort or rinse it in the exam room, and bag or contain it where used. Do not hold contaminated linen against the body. Use leak-resistant containment when wet linen could soak through, and follow the laundry's labeled/color-coded system. Standard handling is based on contamination and exposure risk; isolation-room linen does not automatically become regulated medical waste. Place regulated waste in the facility's designated container without overfilling or compressing bags by hand.

Immunization for Rad Techs

Rad techs should be up to date on all recommended healthcare worker vaccinations per the CDC's Advisory Committee on Immunization Practices (ACIP). These typically include:

Infection Control Scenarios: What Would You Do?

Applying infection control principles in real-world situations is what the ARRT exam — and clinical practice — demands. Consider these common radiology scenarios:

Scenario 1: A patient on contact precautions for MRSA requires a portable AP chest X-ray. When you arrive, the patient is lying supine in bed. You place the DR detector behind the patient's back using a plastic sleeve. After the exposure, you notice the detector slipped partially out of the sleeve. What should you do next?

Solution: Remove the detector from service until it is cleaned and disinfected with a product and method listed in its IFU, observing the EPA label contact time. Report damage or an incompatible-disinfectant question through the facility's equipment/infection-prevention pathway. Routine chart documentation of detector contamination is not generally necessary unless policy requires it.

Scenario 2: You are assigned to fluoroscopy for a symptomatic patient with confirmed C. difficile infection. What preparation is needed?

Solution: Use Contact Precautions with gown and gloves and minimize transport where clinically feasible. Clean and disinfect contaminated patient-care and environmental surfaces with an EPA-registered product carrying a C. difficile sporicidal claim (EPA List K), following the label dilution, application, and wet contact time and each device IFU. Do not use an improvised universal “1:10 bleach” recipe. Alcohol sanitizer does not kill spores, but CDC still prefers it for routine hand hygiene unless hands are visibly soiled; soap and water is encouraged as an additional outbreak precaution. Follow local policy.

Scenario 3: A patient presents to the emergency department with suspected active tuberculosis. The physician orders a PA and lateral chest X-ray. How should this be managed?

Solution: Place the patient in an AIIR and use Airborne Precautions. Prefer imaging in the AIIR when it can meet the clinical need. If transport is medically necessary, coordinate with infection prevention and the receiving department, use a direct route, and have the patient wear a mask if tolerated. Personnel sharing room air wear a fit-tested NIOSH-approved N95 or higher-level respirator. If the imaging room is not an AIIR, follow the facility's approved alternative ventilation and scheduling plan. Keep others out until the facility-calculated clearance interval has elapsed (for ideal mixing, CDC estimates 69 minutes at 6 ACH or 35 minutes at 12 ACH for 99.9% removal).

Scenario 4: A patient with vomiting and diarrhea during a suspected norovirus outbreak has just left CT. What differs from routine turnover?

Solution: Continue Contact Precautions for the duration specified by the outbreak team (CDC recommends at least 48 hours after symptoms resolve, with longer durations considered for complex patients). Wash hands with soap and water after care/contact. Clean vomitus or fecal contamination promptly, then disinfect affected surfaces with an EPA-registered product effective against norovirus (EPA List G), observing its label contact time and device compatibility. Increase cleaning frequency of high-touch surfaces under outbreak policy; do not substitute an unverified bleach recipe.

Summary: The Rad Tech's Infection Control Checklist

Keep these core principles in mind every shift:

  1. Perform hand hygiene at every CDC indication — including before patient contact or an aseptic task, after patient/environment contact, and after gloves
  2. Standard precautions apply to EVERY patient — you cannot tell by looking who is colonized
  3. Reprocess reusable patient-care equipment before reuse and clean environmental high-touch surfaces on the written risk-based schedule
  4. Doff without self-contamination — follow the posted method; hand hygiene is required after PPE removal and whenever contamination occurs
  5. Match product to organism and device — follow the EPA label's wet contact time and the equipment IFU; use List K products for C. difficile spores and List G products for norovirus
  6. Remember transmission categories — Standard Precautions always apply; Contact, Droplet, and Airborne measures are added and sometimes combined
  7. Vaccinate and stay current — hepatitis B, flu, MMR, varicella, Tdap, and COVID-19

Authoritative References

About this resource: Radiography 101 provides educational material for radiologic technology students. This page was evidence-audited against the linked CDC, OSHA, EPA, AIUM, and ACR resources; local infection-prevention policy and device/product instructions control clinical workflow.
📝 ARRT Practice Questions

Test Your Knowledge

Try these ARRT-style multiple choice questions based on this article. Click an option to check your answer — correct answers turn green, wrong ones turn red.

1. A patient with active pulmonary tuberculosis requires a portable chest X-ray. Which type of precautions and PPE are required?
✅ Correct!
Infectious pulmonary tuberculosis requires Airborne Precautions, an AIIR when available, and a fit-tested NIOSH-approved N95 or higher-level respirator. A medical mask is placed on the patient for necessary transport if tolerated; it does not replace the worker's respirator. Gown, gloves, and eye protection are selected under Standard Precautions for the anticipated exposure rather than being automatic for TB alone.
2. A radiologic technologist must wear a gown, mask, eye protection, and gloves for the anticipated exposure. Which option matches a CDC example donning sequence?
✅ Correct!
One CDC donning sequence is gown, mask or respirator, eye protection, then gloves. Doffing is not simply the reverse: CDC provides more than one safe removal method, including gloves, eye protection, gown, then mask/respirator, or gown and gloves together. Remove a respirator only after leaving an airborne-infection room and closing the door. Perform hand hygiene after all PPE is removed and sooner if contamination occurs.
3. According to the Spaulding classification, how should a transvaginal ultrasound probe be processed after each use?
✅ Correct!
A transvaginal probe contacts mucous membranes and is a semicritical device. After every use, remove the cover, clean the probe, and perform high-level disinfection with a compatible FDA-cleared product or system, following all device and reprocessor instructions for concentration, temperature, exposure time, rinsing, drying, and storage. A cover does not replace high-level disinfection; do not memorize a universal chemical concentration or soak time.