N-localizer

{{infobox medical equipment

| name = N-localizer

| acronym =

| synonym =

| image = Photograph of Stereotactic Frame With 3 N-localizers.jpg

| caption = Three N-localizers attached to a stereotactic frame.{{cite book | last1 = Arle | first1 = J | s2cid = 58803140 | editor1-last = Lozano | editor1-first = AM | editor2-last = Gildenberg | editor2-first = PL | editor3-last = Tasker | editor3-first = RR | title = Textbook of Stereotactic and Functional Neurosurgery | chapter = Development of a Classic: The Todd-Wells Apparatus, the BRW, and the CRW Stereotactic Frames | pages = 456–460 | publisher = Springer-Verlag | location = Berlin | year = 2009 | isbn = 978-3-540-69959-0 | doi = 10.1007/978-3-540-69960-6}}

| alt =

| image_size = 300

| specialty = neurosurgery, radiation oncology

| intervention = stereotactic surgery, radiosurgery

| MedlinePlus =

| eMedicine =

| inventor = Russell A. Brown{{cite book | title = U.S. Patent 4608977 | chapter = System Using Computed Tomography as for Selective Body Treatment | year = 1986}}

| invention date =

| manufacturer =

| related =

}}

The N-localizer{{cite book | last1 = Galloway | first1 = RL Jr. | editor1-last = Golby | editor1-first = AJ | title = Image-Guided Neurosurgery | chapter = Introduction and Historical Perspectives on Image-Guided Surgery | pages = 2–4 | publisher = Elsevier | location = Amsterdam | year = 2015 | isbn=978-0-12-800870-6|doi=10.1016/B978-0-12-800870-6.00001-7}} is a device that enables guidance of stereotactic surgery or radiosurgery using tomographic images that are obtained via computed tomography (CT),{{ cite journal |vauthors=Thomas DG, Anderson RE, du Boulay GH | title = CT-guided stereotactic neurosurgery: experience in 24 cases with a new stereotactic system | journal = Journal of Neurology, Neurosurgery & Psychiatry | volume = 47 | issue = 1 | pages = 9–16 | year = 1984 | pmid = 6363629 | doi = 10.1136/jnnp.47.1.9 | pmc=1027634}} magnetic resonance imaging (MRI),{{ cite journal |vauthors=Heilbrun MP, Sunderland PM, McDonald PR, Wells TH Jr, Cosman E, Ganz E | title = Brown-Roberts-Wells stereotactic frame modifications to accomplish magnetic resonance imaging guidance in three planes | journal = Applied Neurophysiology | volume = 50 | issue = 1–6 | pages = 143–152 | year = 1987 | pmid = 3329837 | doi = 10.1159/000100700}} or positron emission tomography (PET).{{ cite journal |vauthors=Maciunas RJ, Kessler RM, Maurer C, Mandava V, Watt G, Smith G | title = Positron emission tomography imaging-directed stereotactic neurosurgery | journal = Stereotactic and Functional Neurosurgery | volume = 58 | issue = 1–4 | pages = 134–140 | year = 1992 | pmid = 1439330 | doi = 10.1159/000098986}} The N-localizer comprises a diagonal rod that spans two vertical rods to form an N-shape (Figure 1) and permits calculation of the point where a tomographic image plane intersects the diagonal rod. Attaching three N-localizers to a stereotactic instrument allows calculation of three points where a tomographic image plane intersects three diagonal rods (Figure 2). These points determine the spatial orientation of the tomographic image plane relative to the stereotactic frame.{{cite book | last1 = Gildenberg | first1 = PL | last2 = Krauss | first2 = JK | s2cid = 58803140 | editor1-last = Lozano | editor1-first = AM | editor2-last = Gildenberg | editor2-first = PL | editor3-last = Tasker | editor3-first = RR | title = Textbook of Stereotactic and Functional Neurosurgery | chapter = History of Stereotactic Surgery | pages = 23 | publisher = Springer-Verlag | location = Berlin | year = 2009 | isbn = 978-3-540-69959-0 | doi = 10.1007/978-3-540-69960-6}}

The N-localizer is integrated with the Brown-Roberts-Wells (BRW),{{ cite journal |vauthors=Heilbrun MP, Roberts TS, Apuzzo ML, Wells TH, Sabshin JK | title = Preliminary experience with Brown-Roberts-Wells (BRW) computerized tomography stereotaxic guidance system | journal = Journal of Neurosurgery | volume = 59 | issue = 2 | pages = 217–222 | year = 1983 | pmid = 6345727 | doi = 10.3171/jns.1983.59.2.0217 }} Kelly-Goerss,{{cite journal | vauthors = Goerss S, Kelly PJ, Kall B, Alker GJ Jr | title = A computed tomography stereotactic adaptation system | journal = Neurosurgery | volume = 10 | issue = 3 | pages = 375–379 | year = 1982 | pmid = 7041006 | doi = 10.1227/00006123-198203000-00014}} Leksell,{{ cite journal |vauthors=Leksell L, Leksell D, Schwebel J | title = Stereotaxis and nuclear magnetic resonance | journal = Journal of Neurology, Neurosurgery & Psychiatry | volume = 48 | issue = 1 | pages = 14–18 | year = 1985 | pmid = 3882889 | doi = 10.1136/jnnp.48.1.14 | pmc=1028176}} Cosman-Roberts-Wells (CRW),{{cite journal |vauthors=Couldwell WT, Apuzzo ML |s2cid=1363168 |title=Initial experience related to the Cosman-Roberts-Wells stereotactic instrument. Technical note |journal=Journal of Neurosurgery |volume=72 |issue=1|pages=145–8 |year=1990 |pmid=2403588 |doi=10.3171/jns.1990.72.1.0145|doi-access=free }} Micromar-ETM03B, FiMe-BlueFrame, Macom, and Adeor-Zeppelin{{cite journal | vauthors = Sedrak M, Alaminos-Bouza AL, Srivastava S | title = Coordinate systems for navigating stereotactic space: how not to get lost | journal = Cureus | volume = 12 | issue = 6 | pages = e8578 | year = 2020 | pmid = 32670714 | doi =10.7759/cureus.8578 | pmc = 7358954 | doi-access = free }} stereotactic frames and with the Gamma Knife radiosurgery system.{{cite book | last1 = Tse | first1 = VCK | last2 = Kalani | first2 = MYS | last3 = Adler | first3 = JR | editor1-last = Chin | editor1-first = LS | editor2-last = Regine | editor2-first = WF | title = Principles and Practice of Stereotactic Radiosurgery | chapter = Techniques of Stereotactic Localization | pages = 25–32 | publisher = Springer | location = New York | year=2015 | isbn = 978-1-4614-8362-5 | doi = 10.1007/978-1-4614-8363-2}}

An alternative to the N-localizer is the Sturm-Pastyr localizer that comprises three rods wherein two diagonal rods form a V-shape and a third, vertical rod is positioned midway between the two diagonal rods (Figure 3).{{ cite journal | vauthors = Sturm V, Pastyr O, Schlegel W, Scharfenberg H, Zabel HJ, Netzeband G, Schabbert S, Berberich W | s2cid = 38864553 | title = Stereotactic computer tomography with a modified Riechert-Mundinger device as the basis for integrated stereotactic neuroradiological investigations | journal = Acta Neurochirurgica | volume = 68 | issue = 1–2 | pages = 11–17 | year = 1983 | pmid = 6344559 | doi = 10.1007/BF01406197 }} The Sturm-Pastyr localizer is integrated with the Riechert-Mundinger and Zamorano-Dujovny stereotactic frames.{{cite book | last1 = Krauss | first1 = JK | s2cid = 58803140 | editor1-last = Lozano | editor1-first = AM | editor2-last = Gildenberg | editor2-first = PL | editor3-last = Tasker | editor3-first = RR | title = Textbook of Stereotactic and Functional Neurosurgery | chapter = The Riechert/Mundinger Stereotactic Apparatus | pages = 487–493 | publisher = Springer-Verlag | location = Berlin | year = 2009 | isbn = 978-3-540-69959-0 | doi = 10.1007/978-3-540-69960-6}}

Compared to the N-localizer, the Sturm-Pastyr localizer is less accurate and necessitates more elaborate calculations to determine the spatial orientation of the tomographic image plane relative to the stereotactic frame.{{ cite journal |vauthors=Alaminos-Bouza AL, Brown RA | title = Comparative accuracies of the N-localizer and Sturm-Pastyr localizer in the presence of image noise | journal = Cureus | volume = 12 | issue = 7 | pages = e9137 | year = 2020 | doi = 10.7759/cureus.9137 | pmid = 32685325 | pmc = 7364427 | doi-access = free }} In contrast to the N-localizer that does not require specification of the pixel size in a tomographic image,{{ cite journal | vauthors = Weaver K, Smith V, Lewis JD, Lulu B, Barnett CM, Leibel SA, Gutin P, Larson D, Phillips T | title = A CT-based computerized treatment planning system for I-125 stereotactic brain implants | journal = International Journal of Radiation Oncology, Biology, Physics | volume = 18 | issue = 2 | year = 1990 | pages = 445–454 | pmid = 2406230 | doi = 10.1016/0360-3016(90)90114-Y}} the Sturm-Pastyr localizer requires precise specification of the pixel size.{{ cite journal | vauthors = Dai J, Zhu Y, Qu H, Hu Y | s2cid = 9196917 | title = An algorithm for stereotactic localization by computed tomography or magnetic resonance imaging | journal = Physics in Medicine and Biology | volume = 46 | issue = 1 | pages = N1–N7 | year = 2001 | pmid = 11197682 | doi = 10.1088/0031-9155/46/1/401 }}

Research conducted four decades after the introduction of the N-localizer{{ cite journal |vauthors=Sedrak M, Alaminos-Bouza AL, Bruna A, Brown RA | title = Monte Carlo simulation of errors for N-localizer systems in stereotactic neurosurgery: novel proposals for improvements | journal = Cureus | volume = 13 | issue = 2 | pages = e13393| year = 2021 | doi = 10.7759/cureus.13393 | pmid = 33758694 | pmc = 7977485 | doi-access = free }} and Sturm-Pastyr localizer{{ cite journal |vauthors=Alaminos-Bouza AL, Brown RA | title = Improved accuracy for the Sturm-Pastyr localizer in the presence of image noise | journal = Cureus | volume = 13 | issue = 9 | pages = e17905 | year = 2021 | doi = 10.7759/cureus.17905 | pmid = 34660100 | pmc = 8509111 | doi-access = free }} has revealed computational techniques that improve the accuracy of both localizers.