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Lung Perfusion Scan with Radioactive Tracer (Lung Ventilation/Perfusion Imaging)

Published: August 9, 2026Updated: August 16, 2026

This test uses a small amount of radioactive material to check how well air reaches your lungs and how well blood flows through your lung blood vessels. It helps identify blockages or other issues that may affect breathing or blood flow.

Quick summary

["A lung V/Q scan helps diagnose conditions like pulmonary embolism or lung diseases by visualizing lung function and blood flow patterns."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
69243-4
Short code
RF Guided Lung PC Absc drn+cath place
Synonyms
RF Guided Lung PC Absc drn+cath place
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
rf
CPT
86430
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

What to Expect Before the Test

You’ll receive a small injection of a radioactive tracer (often called a 'breathing dye') into your arm. A special camera will then take images of your lungs while you breathe normally. The procedure is quick and painless, but you may feel a slight pinch from the injection. Avoid flying for 24 hours after the test due to radiation exposure.

How the Test Works

The radioactive tracer helps highlight areas of your lungs where air reaches normally versus where blood flow may be blocked. The images produced show ventilation (airflow) and perfusion (blood flow) patterns, helping doctors compare them to identify abnormalities.

Common Conditions This Test Helps Diagnose

A lung V/Q scan is often used to diagnose conditions like pulmonary embolism (blood clots in the lungs), chronic lung diseases (e.g., COPD), or other lung-related issues where airflow or blood flow may be uneven.

Preparation Tips

No special preparation is needed, but inform your doctor if you’re pregnant, breastfeeding, or have a history of severe allergies. Avoid caffeine or alcohol before the test if advised, as it may affect your breathing patterns.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Lung V/Q Scan

Frequently asked questions

Why might my doctor order this test?
Your doctor may recommend a lung V/Q scan if you have symptoms like shortness of breath, chest pain, or a history of blood clots. It helps determine whether a blockage in your lungs is causing problems with airflow or blood circulation.
How long will the results take?
Results are typically available within 24 to 48 hours, depending on your healthcare provider’s process. Your doctor will discuss the findings with you during a follow-up visit.
Is the radioactive tracer harmful?
The tracer used in this test is very safe when administered in small amounts. You’ll need to avoid flying for 24 hours after the test to prevent radiation exposure to others, but the radiation from the scan itself is minimal and short-lived.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy