Ryan Alfano1, Glenn S Bauman2, Wei Liu3, Jonathan D Thiessen4, Irina Rachinsky5, William Pavlosky6, John Butler7, Mena Gaed8, Madeleine Moussa9, Jose A Gomez10, Joseph L Chin11, Stephen Pautler12, Aaron D Ward13. 1. Baines Imaging Research Laboratory, London, Canada; London Health Sciences Centre, London, Canada; Western University Department of Medical Biophysics, London, Canada. Electronic address: ralfano2@uwo.ca. 2. London Health Sciences Centre, London, Canada; Western University Department of Medical Biophysics, London, Canada; Western University Department of Oncology, London, Canada. Electronic address: glenn.bauman@lhsc.on.ca. 3. London Health Sciences Centre, London, Canada; Western University Department of Oncology, London, Canada. Electronic address: wei.liu@lhsc.on.ca. 4. Western University Department of Medical Biophysics, London, Canada; St. Joseph's Health Centre, London, Canada; Western University Department of Medical Imaging, London, Canada. Electronic address: jonathan.thiessen@sjhc.london.on.ca. 5. London Health Sciences Centre, London, Canada; Western University Department of Medical Imaging, London, Canada. Electronic address: irina.rachinsky@lhsc.on.ca. 6. Western University Department of Medical Imaging, London, Canada. Electronic address: william.pavlosky@sjhc.london.on.ca. 7. St. Joseph's Health Centre, London, Canada. Electronic address: jbutler@lawsonimaging.ca. 8. Western University Department of Pathology and Laboratory Medicine, London, Canada. Electronic address: mgaed@uwo.ca. 9. London Health Sciences Centre, London, Canada; Western University Department of Pathology and Laboratory Medicine, London, Canada. Electronic address: madeleine.moussa@lhsc.on.ca. 10. London Health Sciences Centre, London, Canada; Western University Department of Pathology and Laboratory Medicine, London, Canada. Electronic address: jose.gomezlemus@lhsc.on.ca. 11. London Health Sciences Centre, London, Canada; Western University Department of Surgery, London, Canada; Western University Department of Oncology, London, Canada. Electronic address: joseph.chin@lhsc.on.ca. 12. St. Joseph's Health Centre, London, Canada; Western University Department of Oncology, London, Canada. Electronic address: stephen.pautler@sjhc.london.on.ca. 13. Baines Imaging Research Laboratory, London, Canada; London Health Sciences Centre, London, Canada; Western University Department of Medical Biophysics, London, Canada; Western University Department of Oncology, London, Canada. Electronic address: award54@uwo.ca.
Abstract
BACKGROUND: PSMA-PET1 has shown good concordance with histology, but there is a need to investigate the ability of PSMA-PET to delineate DIL2 boundaries for guided biopsy and focal therapy planning. OBJECTIVE: To determine threshold and margin combinations that satisfy the following criteria: ≥95% sensitivity with max specificity and ≥95% specificity with max sensitivity. DESIGN, SETTING AND PARTICIPANTS: We registered pathologist-annotated whole-mount mid-gland prostatectomy histology sections cut in 4.4 mm intervals from 12 patients to pre-surgical PSMA-PET/MRI by mapping histology to ex-vivo imaging to in-vivo imaging. We generated PET-derived tumor volumes using boundaries defined by thresholded PET volumes from 1-100% of SUV3max in 1% intervals. At each interval, we applied margins of 0-30 voxels in one voxel increments, giving 3000 volumes/patient. OUTCOME MEASUREMENTS: Mean and standard deviation of sensitivity and specificity for cancer detection within the 2D oblique histologic planes that intersected with the 3D PET volume for each patient. RESULTS AND LIMITATIONS: A threshold of 67% SUV max with an 8.4 mm margin achieved a (mean ± std.) sensitivity of 95.0 ± 7.8% and specificity of 76.4 ± 14.7%. A threshold of 81% SUV max with a 5.1 mm margin achieved sensitivity of 65.1 ± 28.4% and specificity of 95.1 ± 5.2%. CONCLUSIONS: Preliminary evidence of thresholding and margin expansion of PSMA-PET images targeted at DILs validated with histopathology demonstrated excellent mean sensitivity and specificity in the setting of focal therapy/boosting and guided biopsy. These parameters can be used in a larger validation study supporting clinical translation.
BACKGROUND:PSMA-PET1 has shown good concordance with histology, but there is a need to investigate the ability of PSMA-PET to delineate DIL2 boundaries for guided biopsy and focal therapy planning. OBJECTIVE: To determine threshold and margin combinations that satisfy the following criteria: ≥95% sensitivity with max specificity and ≥95% specificity with max sensitivity. DESIGN, SETTING AND PARTICIPANTS: We registered pathologist-annotated whole-mount mid-gland prostatectomy histology sections cut in 4.4 mm intervals from 12 patients to pre-surgical PSMA-PET/MRI by mapping histology to ex-vivo imaging to in-vivo imaging. We generated PET-derived tumor volumes using boundaries defined by thresholded PET volumes from 1-100% of SUV3max in 1% intervals. At each interval, we applied margins of 0-30 voxels in one voxel increments, giving 3000 volumes/patient. OUTCOME MEASUREMENTS: Mean and standard deviation of sensitivity and specificity for cancer detection within the 2D oblique histologic planes that intersected with the 3D PET volume for each patient. RESULTS AND LIMITATIONS: A threshold of 67% SUV max with an 8.4 mm margin achieved a (mean ± std.) sensitivity of 95.0 ± 7.8% and specificity of 76.4 ± 14.7%. A threshold of 81% SUV max with a 5.1 mm margin achieved sensitivity of 65.1 ± 28.4% and specificity of 95.1 ± 5.2%. CONCLUSIONS: Preliminary evidence of thresholding and margin expansion of PSMA-PET images targeted at DILs validated with histopathology demonstrated excellent mean sensitivity and specificity in the setting of focal therapy/boosting and guided biopsy. These parameters can be used in a larger validation study supporting clinical translation.
Authors: Christopher W Smith; Ryan Alfano; Douglas Hoover; Kathleen Surry; David D'Souza; Jonathan Thiessen; Irina Rachinsky; John Butler; Jose A Gomez; Mena Gaed; Madeleine Moussa; Joseph Chin; Stephen Pautler; Glenn S Bauman; Aaron D Ward Journal: Phys Imaging Radiat Oncol Date: 2021-07-30
Authors: Wei Liu; Andrew Loblaw; David Laidley; Hatim Fakir; Lucas Mendez; Melanie Davidson; Zahra Kassam; Ting-Yim Lee; Aaron Ward; Jonathan Thiessen; Jane Bayani; John Conyngham; Laura Bailey; Joseph D Andrews; Glenn Bauman Journal: Front Oncol Date: 2022-04-13 Impact factor: 5.738