What type of artifacts may arise from using CT for attenuation correction?

Beam hardening artifacts are a common issue that can arise from the use of computed tomography (CT) for attenuation correction in positron emission tomography (PET). When X-rays pass through dense materials, such as bone or contrast agents, lower-energy photons are absorbed more than higher-energy photons. As a result, the average energy of the remaining X-rays increases, causing discrepancies in the attenuation values that are used to correct PET images. This can lead to areas of under- or over-correction in the resulting PET images, manifesting as streaks or dark bands.

Understanding beam hardening artifacts is crucial for accurately interpreting PET images because they can obscure the true distribution of radiotracers and potentially lead to misdiagnosis or misinterpretation of clinical findings. Proper calibration and correction techniques are important for mitigating these artifacts and improving the quality of the images produced.