Post-radioembolization yttrium-90 PET/CT - part 1: diagnostic reporting

Area of Science:

• Nuclear Medicine
• Radiology
• Oncology

Background:

• Yttrium-90 (90Y) positron emission tomography with integrated computed tomography (PET/CT) offers advanced imaging capabilities over traditional 90Y bremsstrahlung single-photon emission computed tomography with integrated computed tomography (SPECT/CT).
• The study implemented 90Y PET/CT as an adjunct to 90Y SPECT/CT for diagnostic reporting following radioembolization, building on positive initial experiences.

Purpose of the Study:

• To compare the diagnostic performance of 90Y PET/CT versus 90Y SPECT/CT in the post-radioembolization setting.
• To evaluate the ability of 90Y PET/CT to assess technical success, detect non-target activity, and confirm 90Y activity within targeted tumor vascular thrombosis.

Main Methods:

• A retrospective review of 44 paired 90Y PET/CT and 90Y SPECT/CT scans was conducted over one year.
• Image resolution, technical success confirmation, non-target activity detection, and tumor vascular thrombosis assessment were compared.
• 90Y PET/CT findings were corroborated using various methods, including SPECT/CT, follow-up imaging, and clinical record review.

Main Results:

• 90Y PET/CT consistently outperformed 90Y SPECT/CT in qualitative analysis, including assessment of non-target activity and tumor vascular thrombosis.
• A novel technique for detecting non-target activity based on activity patterns relative to anatomy was proposed.
• While generally superior, challenges remain in detecting non-target activity in viscera adjacent to the liver due to potential mis-registration.

Conclusions:

• Post-radioembolization 90Y PET/CT is clinically superior to 90Y SPECT/CT for evaluating both target and non-target Yttrium-90 activity.
• Adherence to proper diagnostic reporting techniques and maintaining continuity of care are essential for the effective clinical application of 90Y PET/CT.