Radiation Lung Injury

Preliminary Diagnosis: Radiation Lung Injury

I. What imaging technique is first-line for this diagnosis?

Computed tomography (CT) chest without contrast

II. Describe the advantages and disadvantages of this technique for diagnosing radiation lung injury.

Advantages

• Diagnostic of radiation lung injury.

• Can better differentiate radiation lung injury from tumor recurrence or infection than other imaging modalities.

• Shows the ground glass opacities related to early radiation lung injury, even when chest radiography is normal.

• Better shows radiation lung injury confined to a radiation treatment portal than radiography.

Disadvantages

• Exposes the patient to more ionizing radiation than radiography.

III. What are the contraindications for the first-line imaging technique?

Contraindicated in pregnant women, especially during the first and second trimesters.

IV. What alternative imaging techniques are available?

• High resolution CT (HRCT) chest without contrast

• Chest radiography (CXR)

• Positron emission tomography (PET)/CT chest,

V. Describe the advantages and disadvantages of the alternative techniques for diagnosing radiation lung injury.

HRCT chest without contrast

Advantages

• Optimal tool for visualization and diagnosis of radiation lung injury.

• Can differentiate radiation lung injury from tumor recurrence or infection.

Disadvantages

• Standard CT chest is usually just as diagnostic as HRCT.

• HRCT exposes the patient to ionizing radiation.

CXR with posteroanterior (PA) and lateral projections

Advantages

• May be diagnostic of radiation lung injury.

• Can show manifestations of early and chronic radiation lung injury, and can track the progression of disease.

Disadvantages

• May be negative during early radiation lung injury, even when CT shows the disease.

• Less sensitive for delineation of radiation lung injury from tumor recurrence or infection.

PET/CT chest

Advantages

• Very sensitive for identifying tumor recurrence within chronic radiation lung injury/scarring.

• Great tool for staging and follow-up of chest malignancy.

Disadvantages

• Early radiation lung injury (i.e., first few weeks) can have increased radiotracer activity and mimic tumor recurrence on PET/CT.

• Expensive.

• Exposes the patient to more ionizing radiation than radiography.

• Requires more patient cooperation than CT.

• Requires good blood sugar control, and may have to be rescheduled if the patient is hyperglycemic.

• Has to be delayed for a few hours after the patient receives insulin therapy.

VI. What are the contraindications for the alternative imaging techniques?

HRCT

• Contraindicated in pregnant women, especially in the first and second trimesters.

CXR

• Has no significant contraindication. Consent may be required for pregnant patients at some institutions.

PET/CT

• Contraindicated in pregnant women, especially in the first and second trimesters.