title: The next evolution in radioguided surgery: breast cancer related sentinel node localization using a freehandSPECT-mobile gamma camera combination.
abstract: Accurate pre- and intraoperative identification of the sentinel node (SN) forms the basis of the SN biopsy procedure. Gamma tracing technologies such as a gamma probe (GP), a 2D mobile gamma camera (MGC) or 3D freehandSPECT (FHS) can be used to provide the surgeon with radioguidance to the SN(s). We reasoned that integrated use of these technologies results in the generation of a "hybrid" modality that combines the best that the individual radioguidance technologies have to offer. The sensitivity and resolvability of both 2D-MGC and 3D-FHS-MGC were studied in a phantom setup (at various source-detector depths and using varying injection site-to-SN distances), and in ten breast cancer patients scheduled for SN biopsy. Acquired 3D-FHS-MGC images were overlaid with the position of the phantom/patient. This augmented-reality overview image was then used for navigation to the hotspot/SN in virtual-reality using the GP. Obtained results were compared to conventional gamma camera lymphoscintigrams. Resolution of 3D-FHS-MGC allowed identification of the SNs at a minimum injection site (100 MBq)-to-node (1 MBq; 1%) distance of 20 mm, up to a source-detector depth of 36 mm in 2D-MGC and up to 24 mm in 3D-FHS-MGC. A clinically relevant dose of approximately 1 MBq was clearly detectable up to a depth of 60 mm in 2D-MGC and 48 mm in 3D-FHS-MGC. In all ten patients at least one SN was visualized on the lymphoscintigrams with a total of 12 SNs visualized. 3D-FHS-MGC identified 11 of 12 SNs and allowed navigation to all these visualized SNs; in one patient with two axillary SNs located closely to each other (11 mm), 3D-FHS-MGC was not able to distinguish the two SNs. In conclusion, high sensitivity detection of SNs at an injection site-to-node distance of 20 mm-and-up was possible using 3D-FHS-MGC. In patients, 3D-FHS-MGC showed highly reproducible images as compared to the conventional lymphoscintigrams.
authors.affiliation: Interventional Molecular Imaging Laboratory and Nuclear Medicine section, Department of Radiology, Leiden University Medical Center Albinusdreef 2, PO Box 9600, 2300 RC, Leiden, The Netherlands ; Department of Head and Neck Surgery and Oncology, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands.
authors.forename: Thijs
authors.initials: T
authors.lastname: Engelen
authors.affiliation: Interventional Molecular Imaging Laboratory and Nuclear Medicine section, Department of Radiology, Leiden University Medical Center Albinusdreef 2, PO Box 9600, 2300 RC, Leiden, The Netherlands.
authors.forename: Beatrice Mf
authors.initials: BM
authors.lastname: Winkel
authors.affiliation: Interventional Molecular Imaging Laboratory and Nuclear Medicine section, Department of Radiology, Leiden University Medical Center Albinusdreef 2, PO Box 9600, 2300 RC, Leiden, The Netherlands.
authors.forename: Daphne Dd
authors.initials: DD
authors.lastname: Rietbergen
authors.affiliation: Interventional Molecular Imaging Laboratory and Nuclear Medicine section, Department of Radiology, Leiden University Medical Center Albinusdreef 2, PO Box 9600, 2300 RC, Leiden, The Netherlands ; Department of Nuclear Medicine, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands.
authors.forename: Gijs H
authors.initials: GH
authors.lastname: KleinJan
authors.affiliation: Department of Nuclear Medicine, Hospital Clinic-Barcelona Villarroel 170. 08036 Barcelona, Spain.
authors.forename: Sergi
authors.initials: S
authors.lastname: Vidal-Sicart
authors.affiliation: Interventional Molecular Imaging Laboratory and Nuclear Medicine section, Department of Radiology, Leiden University Medical Center Albinusdreef 2, PO Box 9600, 2300 RC, Leiden, The Netherlands ; Department of Nuclear Medicine, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands.
authors.forename: Renato A Valdés
authors.initials: RA
authors.lastname: Olmos
authors.affiliation: Interventional Molecular Imaging Laboratory and Nuclear Medicine section, Department of Radiology, Leiden University Medical Center Albinusdreef 2, PO Box 9600, 2300 RC, Leiden, The Netherlands ; Department of Urology, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands.
authors.forename: Nynke S
authors.initials: NS
authors.lastname: van den Berg
authors.affiliation: Interventional Molecular Imaging Laboratory and Nuclear Medicine section, Department of Radiology, Leiden University Medical Center Albinusdreef 2, PO Box 9600, 2300 RC, Leiden, The Netherlands ; Department of Head and Neck Surgery and Oncology, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands ; Department of Urology, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital Plesmanlaan 121, 1066CX, Amsterdam, The Netherlands.
authors.forename: Fijs Wb
authors.initials: FW
authors.lastname: van Leeuwen
keywords: Sentinel node; breast cancer; freehandSPECT; mobile gamma camera; navigation; nuclear medicine; radioguided surgery