1. Low dose vs. Diagnostic CT Chris Semine MD 1/11/11
PET-CT
Low dose vs. Diagnostic CT
Chris Semine MD 1/11/11

2. Low Dose PET-CT
Standard PET scan is performed and fused to a low dose CT scan used to identify the location (localize) the foci of abnormal uptake
The “CT” is not a diagnostic examination. The radiation dosage is too low to generate fully diagnostic images.

3. PET/ Diagnostic CT
Every case of PET has a concurrent diagnostic quality (full radiation dose CT scan with or without contrast) of the head, neck, chest, abdomen and pelvis.
Five diagnostic level CT examinations are performed and fused to the PET regardless of whether the patient needs them at this time or not.

4. Radiation exposure Loc PET-CT PET 5mSV Loc CT 15 mSV TOTAL: 20mSV
Dx PET-CT
PET 5mSV
Head CT 4 mSV
Neck CT 6 mSV
Chest CT 7 mSV
Abd CT 7.5 mSV
Pelvis CT 7.5 mSV
TOTAL: 42 mSV

5. COST Localizing PET-CT PET: $1000 Loc CT: $0 TOTAL: $1000 Dx PET-CT
CT Head $600
CT Neck $800
CT Chest $800
CT Abdomen $800
CT Pelvis $800
TOTAL: $4800

6. Conclusions:
Patients that need to have diagnostic CTs of chest, abdomen, and pelvis at approximately the same time as the PET are candidates to have the combined PET and diagnostic CT examinations (with or without contrast, as indicated).
Patient who are not due to have diagnostic CTs of the head, neck, chest, abdomen and pelvis at the same time as the PET would be better served to have a PET/CT with localizing CT only, and have the diagnostic CT (not necessarily all 5 CTs) done at the appropriate time.