Clinical Indications forPET.CT Imaging

in Urology

Thomas F. Heston, MD, FACNM, FASNC, FAAFP

Why PET/CT Works:The Warburg Effect

● Normal Cells● Low rate of glycolysis

● Aerobic metabolism

● Most Cancer Cells● High rate of glycolysis

● Anaerobic metabolism

Imaging Glycolysis: 18-F FDG

e+ e-

511 γ

511 γ

Imaging the glycolisis: Positron Emission Tomography

Imaging the Warburg Effect: Why it Works

The Warburg Effect: Cancer Types

● Nearly all solid tissue tumors● Lung

● Colon

● Breast

● Notable Exceptions● Slow growth: prostate cancer (use 18F-fluoride)

● Mucinous: BAC

● Early Disease: tumors < 0.5 cm

18-F FDG PET/CT Works Because:

● Tumor cells have increased glycolysis

● O-18 enriched water bombarded by protons

---> F-18 ---> 18F-FDG

● FDG hits a metabolic dead end

● PET images 18F positron emissions

● CT allows anatomic localization

Imaging the Warburg Effect: Normal vs Abnormal

Normal PET/CT

Abnormal PET/CT

Prostate Cancer

F-18 NaF vs Tc-99m MDP

● PET/CT more accurate● Sensitivity: 90% vs 80%

● Specificity: 95%+ vs 90%

● PET/CT more comfortable● Shorter uptake time

● Shorter scan time

PET/CT vs SPECT

http://www.cms.gov/mcd/publiccomment_popup.asp?comment_id=19917

Dual Tracer Acquisition

PET/CT in Prostate Cancer: Conclusions

● Workup: in selected patients only

● Restaging in pts with PSA relapse● Nodal disease

● Osseous disease

● Dual FDG / NaF imaging

Renal Cell Carcinoma

PET/CT in Renal Cell Carcinoma

● FDG excreted by the urinary tract

● Indications● Staging high risk patients for metastatic

disease

● When other imaging is non-diagnostic

Research Studies

PET/CT vs Bone Scan - 1● 44 pts with high risk prostate cancer

● Gleson score >= 8 or PSA >= 20 ng/mL

● Prevalence: 52% with bony mets

● Gold Standard● All imaging results including MRI & CT

● Biopsy in selected cases

● Clinical follow-upEven-Sapir E, Metser U, Mishani E, Lievshitz G, Lerman H, Leibovitch I. The detection of bone metastases in patients with high-risk prostate cancer: 99mTc-MDP Planar bone scintigraphy, single- and multi-field-of-view SPECT, 18F-fluoride PET, and 18F-fluoride PET/CT. J Nucl Med. 2006 Feb;47(2):287-97.

PET/CT vs Bone Scan - 2

Even-Sapir E, Metser U, Mishani E, Lievshitz G, Lerman H, Leibovitch I. The detection of bone metastases in patients with high-risk prostate cancer: 99mTc-MDP Planar bone scintigraphy, single- and multi-field-of-view SPECT, 18F-fluoride PET, and 18F-fluoride PET/CT. J Nucl Med. 2006 Feb;47(2):287-97.

● Agreement: 22/42 (52%)

● MDP understaged 13/42 (31%)

● MDP overstaged 7/42 (17%)

FDG PET/CT vs MDP Bone Scan - 1

● 70 pts with a variety of cancers with bone mets

● Per Patient Basis: PET/CT 97% vs BS 86% sensitivity

● Per Lesion Basis: PET/CT 92% vs BS 70% sensitivity

● Incidental Findings: in 24 patients, organ metastases

were found and in 7/7 pts with unknown primary, the

primary was found

Ozülker T, Küçüköz Uzun A, Ozülker F, Ozpaçac T. Comparison of (18)F-FDG-PET/CT with (99m)Tc-MDP bone scintigraphy for the detection of bone metastases in cancer patients. Nucl Med Commun. 2010 Jun;31(6):597-603.

Thank You!