SU-D-217BCD-04: How Do We Know How Low Can We Go in Lung Cancer Screening CT?

Area of Science:

• Radiology
• Medical Imaging
• Oncology

Background:

• Lung cancer screening with low-dose computed tomography (CT) aims to reduce mortality.
• Optimizing radiation dose is crucial to minimize risks associated with CT scans.
• Establishing acceptable dose levels ensures effective screening without unnecessary radiation exposure.

Purpose of the Study:

• To develop and demonstrate a method for determining the acceptable radiation dose for lung cancer screening CT.
• To evaluate image quality at various reduced radiation dose levels for lung cancer screening.

Main Methods:

• Twenty patients undergoing routine chest CT were included.
• Noise insertion software simulated reduced radiation doses (12.5%, 25%, 50% of original).
• Three thoracic radiologists blindly assessed image quality for diagnostic and screening tasks using a 5-point scale.

Main Results:

• Lung cancer screening CT achieved 100% acceptable image quality at 25% of the original dose.
• Routine diagnostic chest CT required higher doses for acceptable image quality, especially for soft tissue evaluation.
• Acceptable image quality for screening was maintained even at 12.5% of the original dose for lung tissue.

Conclusions:

• A radiation dose of 25% of that used for routine diagnostic chest CT is sufficient for lung cancer screening.
• This fourfold dose reduction is comparable to doses used in the National Lung Screening Trial (NLST).
• The findings support the use of significantly reduced radiation doses for effective lung cancer screening CT.