title: Remission spectrometry for blood vessel detection during stereotactic biopsy of brain tumors.
abstract: Stereotactic biopsy is used to enable diagnostic confirmation of brain tumors and treatment planning. Despite being a well-established technique, it is related to significant morbidity and mortality rates mostly caused by hemorrhages due to blood vessel ruptures. This paper presents a method of vessel detection during stereotactic biopsy that can be easily implemented by integrating two side-view fibers into a conventional side-cutting biopsy needle. Tissue within the needle window is illuminated through the first fiber; the second fiber detects the remitted light. By taking the ratio of the intensities at two wavelengths with strongly differing hemoglobin absorption, blood vessels can be recognized immediately before biopsy sampling. Via ray tracing simulations and phantom experiments, the dependency of the remission ratio R = I578/I650on various parameters (blood oxygenation, fiber-to-vessel and inter-fiber distance, vessel diameter and orientation) was investigated for a bare-fiber probe. Up to 800-1200 µm away from the probe, a vessel can be recognized by a considerable reduction of the remission ratio from the background level. The technique was also successfully tested with a real biopsy needle probe on both optical phantoms and ex-vivo porcine brain tissue, thus showing potential to improve the safety of stereotactic biopsy. Dual-wavelength remission measurement for the detection of blood vessels during stereotactic biopsy.
authors.affiliation: Laser-Forschungslabor, LIFE Center, University Hospital of Munich, Munich, Germany.|Department of Urology, University Hospital of Munich, Munich, Germany.
authors.forename: Niklas A
authors.initials: NA
authors.lastname: Markwardt
authors.affiliation: Laser-Forschungslabor, LIFE Center, University Hospital of Munich, Munich, Germany.|Department of Urology, University Hospital of Munich, Munich, Germany.
authors.forename: Herbert
authors.initials: H
authors.lastname: Stepp
authors.affiliation: Department of Applied Sciences and Mechatronics, Munich University of Applied Sciences, Munich, Germany.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Franz
authors.affiliation: Laser-Forschungslabor, LIFE Center, University Hospital of Munich, Munich, Germany.|Department of Urology, University Hospital of Munich, Munich, Germany.
authors.forename: Ronald
authors.initials: R
authors.lastname: Sroka
authors.affiliation: MRC Systems GmbH, Heidelberg, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Goetz
authors.affiliation: Burdenko Neurosurgery Institute, Moscow, Russia.
authors.forename: Petr
authors.initials: P
authors.lastname: Zelenkov
authors.affiliation: Laser-Forschungslabor, LIFE Center, University Hospital of Munich, Munich, Germany.|Department of Urology, University Hospital of Munich, Munich, Germany.
authors.forename: Adrian
authors.initials: A
authors.lastname: Rühm
mesh_terms: D000818:Animals; D001706:Biopsy / Q000379:methods*; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging; D001932:Brain Neoplasms / Q000098:blood supply* / Q000000981:diagnostic imaging*; D013057:Spectrum Analysis; D013238:Stereotaxic Techniques; D013552:Swine
keywords: blood vessel detection; glioblastoma multiforme; hemorrhage; optical phantoms; ray tracing simulations; stereotactic biopsy