In situ histopathological correlation of FDG uptake by autoradiography of needle biopsy specimens obtained under PET-CT guidance

Objectives To study correlations between FDG uptake and histopathology with high spatial accuracy.

Methods Fresh core needle biopsy specimens were exposed on digital autoradiography (ARG) plates for 10 minutes after extraction and before routine histopathology evaluation. Different disease and tumor locations were targeted under an IRB approved protocol. Activity profiles along the specimen were assessed relative to previously generated calibration curves obtained with in-house developed F-18 standards for 18G and 20G core needles. The ARG image was fused with the PET/CT images using the Computational Environment for Radiation Research (CERR) software. Specimen FDG uptake - histopathology - PET image correlations were visually examined.

Results Readable ARG images of the biopsy specimens were obtained for 8 of the first 10 patients. Activity quantification was prevented by the presence of bone in 2 specimens and by the irregular shape of another specimen obtained with an aspiration needle. Specimen fragmentation during pathology processing affected few cases and prevented 1 correlation. Two-way correlations between ARG images, histopathology and PET were found in 5 of 6 cases for ARG vs. PET, in 5 of 6 cases for ARG vs. histopathology, and in 8 of 10 cases for PET vs. histopathology.

Conclusions Quantitative Autoradiography of Biopsy Specimens (QABS) obtained under PET/CT guidance allows spatially accurate in situ association of specimen tracer uptake and histopathological findings with the PET/CT images. Fusing this data for peripheral needle placements promises an opportunity to adjust the display window setting of the PET image to more accurately represent the tumor margin at the point of biopsy.

Research Support Acknowledgements for support and contribution to this work are due to Dr. Joseph O. Deasy, PhD, Dr. Ellen Yorke Ph.D., Dr. Jeremy C. Durack, MD, Dr. Joseph P. Erinjeri, MD, Dr. Majid Maybody, MD, Dr. Robert H. Siegelbaum, MD, Dr. Constantinos T. Sofocleous MD, all from Memorial Sloan-Kettering Cancer Center (MSKCC) and to Dr. Irene A. Burger, MD, from University Hospital, Zurich. This work is supported in part by the Department of Medical Physics at MSKCC and by Biospace Lab, S.A.