Feasibility of in situ, high-resolution correlation of tracer uptake with histopathology by quantitative autoradiography of biopsy specimens obtained under 18F-FDG PET/CT guidance.
Core biopsies obtained using PET/CT guidance contain bound radiotracer and therefore provide information about tracer uptake in situ. Our goal was to develop a method for quantitative autoradiography of biopsy specimens (QABS), to use this method to correlate (18)F-FDG tracer uptake in situ with histopathology findings, and to briefly discuss its potential application.


METHODS
Twenty-seven patients referred for a PET/CT-guided biopsy of (18)F-FDG-avid primary or metastatic lesions in different locations consented to participate in this institutional review board-approved study, which complied with the Health Insurance Portability and Accountability Act. Autoradiography of biopsy specimens obtained using 5 types of needles was performed immediately after extraction. The response of autoradiography imaging plates was calibrated using dummy specimens with known activity obtained using 2 core-biopsy needle sizes. The calibration curves were used to quantify the activity along biopsy specimens obtained with these 2 needles and to calculate the standardized uptake value, SUVARG. Autoradiography images were correlated with histopathologic findings and fused with PET/CT images demonstrating the position of the biopsy needle within the lesion. Logistic regression analysis was performed to search for an SUVARG threshold distinguishing benign from malignant tissue in liver biopsy specimens. Pearson correlation between SUVARG of the whole biopsy specimen and average SUVPET over the voxels intersected by the needle in the fused PET/CT image was calculated.


RESULTS
Activity concentrations were obtained using autoradiography for 20 specimens extracted with 18- and 20-gauge needles. The probability of finding malignancy in a specimen is greater than 50% (95% confidence) if SUVARG is greater than 7.3. For core specimens with preserved shape and orientation and in the absence of motion, one can achieve autoradiography, CT, and PET image registration with spatial accuracy better than 2 mm. The correlation coefficient between the mean specimen SUVARG and SUVPET was 0.66.


CONCLUSIONS
Performing QABS on core-biopsy specimens obtained using PET/CT guidance enables in situ correlation of (18)F-FDG tracer uptake and histopathology on a millimeter scale. QABS promises to provide useful information for guiding interventional radiology procedures and localized therapies and for in situ high-spatial-resolution validation of radiopharmaceutical uptake.
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York INSERM, UMR1101, LaTIM, Brest, France kirova@mskcc.org.
Louise M
LM
Fanchon
Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York.
Snjezana
S
Dogan
Department of Pathology, Memorial Sloan-Kettering Cancer Center, New York, New York.
Andre L
AL
Moreira
Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York; and.
Sean A
SA
Carlin
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York.
C Ross
CR
Schmidtlein
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York.
Ellen
E
Yorke
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York.
Aditya P
AP
Apte
Department of Nuclear Medicine, University Hospital, Zurich, Switzerland.
Irene A
IA
Burger
Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York; and.
Jeremy C
JC
Durack
Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York; and.
Joseph P
JP
Erinjeri
Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York; and.
Majid
M
Maybody
Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York; and.
Heiko
H
Schöder
Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York; and.
Robert H
RH
Siegelbaum
Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York; and.
Constantinos T
CT
Sofocleous
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York.
Joseph O
JO
Deasy
Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, New York; and.
Stephen B
SB
Solomon
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York.
John L
JL
Humm
Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, New York kirova@mskcc.org.
Assen S
AS
Kirov
D001345:Autoradiography / Q000379:methods*; D001706:Biopsy / Q000379:methods*; D001859:Bone Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D002138:Calibration; D005240:Feasibility Studies; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008113:Liver Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D016015:Logistic Models; D008175:Lung Neoplasms / Q000000981:diagnostic imaging / Q000473:pathology; D009339:Needles; D049268:Positron-Emission Tomography / Q000379:methods*; D011336:Probability; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D014057:Tomography, X-Ray Computed / Q000379:methods*
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
PET/CT; autoradiography; biopsy; histopathology; oncology