CLRS 321: Nuclear Medicine Physics and Instrumentation I Unit V: Introduction to Gamma Camera Lecture 3: Gamma Camera Use and Care; Non-anger gamma imaging devices CLRS 321: Nuclear Medicine Physics and Instrumentation I Image from Molecular Breast Imaging. Mercy Medical Center. Available at http://mercymedicalcenter.chsli.org/molecular-breast-imaging . Accessed 28 Nov 2017

Objectives Regarding gamma camera systems, discuss the need for the following as well as the entity responsible for providing each: Energy corrections Linearity corrections Uniformity correction map Autotuning of PMTs Describe gamma camera installment considerations Discuss patient positioning considerations Describe various imaging modes employed using gamma cameras Describe best-practice image timing for planar imaging Describe unconventional single-emission nuclear medicine imaging systems

Physical Construction Moveable gantry supports heavy camera heads Heads have aluminum cover and heavy collimators PMTs are shielded with Mu metal to prevent influence of internal and external magnetic fields Most now have tables that translate instead of gantries Cameras typically have… Hand control Digitize version of a P-scope for positioning Computer workstation for acquisition setup and processing Collimator exchange system (may be automated)

Installation considerations Stable room environment Cool and well-ventilated Temperature changes >9 degrees/hour may crack crystal Best to have a uninterruptable power supply (UPS) Has a battery that kicks in on fly Prevents damage from power surges Walls are transparent to gamma energy—so be careful where your cameras will be pointing Image from General Nuclear Medicine. RadiologyInfo .org available at https://www.radiologyinfo.org/en/info.cfm?pg=gennuclear accessed 12 Mar 17

Patient positioning Just about any position.. Supine Prone Upright Tail-on-detector (TOD) Plantar Palmar Image from Nuclear Medicine (Gamma Camera). Doncaster and Bassetlaw Teaching Hospitals. NHS.uk availabe at http://www.dbh.nhs.uk/our_services/medical_imaging/gamma_camera.aspx accessed 12 Mar 17.

Imaging modes Static (planar) Whole-body Dynamic Timing consideration important Stopping according to time--more time makes for more info, but increases chances of patient movement Stopping according to counts--when comparing views of different areas, best to be consistent with time instead of counts Count-density—image is stopped when the desired counts per cm2 reach a certain level Whole-body Dynamic SPECT (180 and 360 degree) http://www.sghhealth4u.com.sg/Health4U/nuclear/graphics/insite/bone_scan_diagram.jpg

Care of Gamma Cameras Crystal very fragile Minimize uncollimated exposure and use means to protect crystal Lead is soft and collimators can be easily damaged by imaging bed or collimator exchanger Crystals and PMTs degrade over time Image from SPECT gamma camera / CT scanner / for SPECT full body / full-body tomography Discovery™ NM/CT 670 available at http://www.medicalexpo.com/prod/ge-healthcare/product-70717-430769.html#product-item_429263 accessed 12 Mar 17.

Solid State Gamma Camera Uses an array of many scintillation crystals (either Cadmium Zinc Telluride or Thallium Activated Cesium Iodide) Uses semiconductor detectors(as discussed under scintillation detectors) in a pixelated array. Each semiconductor has its own photodiode (instead of PMT) Creates a positioning matrix rather than the positioning logic of the Anger system. http://www.asnc.org/section_96.cfm

Solid State Gamma Camera—Digirad System 4,096 CsI(Tl) Crystals and Photodiodes Good Efficiency Hi Noise Potential Very Good Resolution (2mm Intrinsic) “Pixelated” FOV property lends itself to digitization Consistent performance across entire FOV http://www.digirad.com/tech_detector.shtm#

Cadmium Zinc Telluride Crystals http://www.answers.com/topic/cadmium-zinc-telluride?cat=technology http://www.answers.com/topic/bonded-assembly-jpg

Images from Digirad System http://www.digirad.com/tech_results.shtm

D-SPECT http://www.cyclopharma.fr/anglais/dispositifs_medicaux.html

Breast-specific Imaging Currently referred to as molecular breast imaging (or MBI) Uses Tc-99m Sestamibi (MiralumaTM) Mitochondria of breast tumors have an avidity for Sestamibi Image from MBI Cast Wider Net for Breast Cancer Diagnosis. Auntminnie.com available at http://www.auntminnie.com/index.aspx?sec=spt&sub=mbi&pag=dis&itemID=91850 accessed 12 Mar 17 Image from Molecular Breast Imaging May Increase Cancer Detection for Women with Dense Breasts. RSNA.org Available at http://www.rsna.org/News.aspx?id=15733 accessed 12 Mar 17

That’s Enough! (for this semester) From Scientific American.com. Available at: http://www.scientificamerican.com/article.cfm?id=impact-and-the-brain. Accessed November 28, 2011.