HYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINE
HYBRID IMAGINGIN CONVENTIONALNUCLEAR MEDICINEA TECHNOLOGIST’S GUIDEProduced with the kind support of
Table of contents ForewordAndrea Santos4 IntroductionMarius Mada, MarieClaire Attard and Agata Pietrzak6Chapter 1 Physics and reconstruction methods for SPECT/CTAnne Larsson Strömvall9Chapter 2 QC of Hybrid SystemsSebastijan Rep31Chapter 3 Quantitative SPECTJohn Dickson45Chapter 4 Bone Scintigraphy65Vladimir Vukomanovic, Vesna Ignjatovic, Milos Stevic,Nenad Mijatovic and Marija Z. JeremicChapter 5 Lung ImagingBozena Birkenfeld, Jacek Iwanowski and Monika Gawron81Chapter 6 Clinical use of SPECT/CT:imaging of neuroendocrine tumours and sentinel node imaging 95Luka LezaicChapter 7 Myocardial Perfusion ImagingMarieClaire Attard and Hein Verberne105Chapter 8 Accomplishing Good Diagnostic Examinationsfrom the Paediatric PopulationPietro Zucchetta117Chapter 9 Inflammation/Infection StudiesAndor W. J. M. Glaudemans129Chapter 10 Parathyroid and Thyroid ImagingMartin Gotthardt143Chapter 11 The Contribution of Hybrid Imaging to Radionuclide therapyJan Taprogge, Paul Gape, Carla Abreu and Glenn Flux163EANM TECHNOLOGIST’S GUIDEHYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINE3
FOREWORDFOREWORDForewordSince the introduction of hybrid imaging, nuclear medicine hasexperienced a great development within its practices and conventionalnuclear medicine has benefited greatly from the application of hybridimaging.The definition of hybrid being theproduct of combining two or moredifferent things, it is evident that thepurpose of any such combination is toextract the best qualities from them bothand minimise their respective limitations.It is thus vitally important that bothtechnologies are profoundly understood,not only in their individual characteristicsbut also in their combined use. The desired synergies can only be realised if thehybrid application makes optimum use ofthe respective technologies.Nuclear medicine technologists interactdirectly with the patient in the imagingcontext, and are thus the professionals4that bridge the gap between all thebackground science and engineeringand the patient. These professionals areequipped with the skills necessary touse the imaging technology, for whichthey require a combination of theoreticaland practical competencies. With this inmind, this book starts by outlining thebasic concepts of physics, reconstructionmethods and quality control proceduresthat allow image formation. This is followedby a discussion of clinical applicationsof hybrid conventional imaging, with apractical focus to facilitate implementationand develop good practice. The laterchapters of the book address the topicEANM TECHNOLOGIST’S GUIDEHYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINEsupport. Last but not least, I thank theof molecular therapy and outline hybridEANM Board and Executive Office for theirimaging’s contribution to this field.tireless efforts which have made this seriesIt is with immense gratitude that Iof publications possible.highlight the great contribution madeHybrid Imaging in Conventional Nuclearby all the authors who gave theirMedicine was only possible thanks to theknowledge to this project. Here, specialcontribution of everyone mentionedacknowledgment is due to the Physics,before. Thank you all very much!Paediatric and Cardiovascular Committeesof the EANM, who have supported usthroughout as well as furnishing their owncontribution.Andrea SantosA special word of appreciation goes Chair, EANM Technologist Committeeto the EANM-TC editorial group, whohave dedicated their time to putting thispublication together, and also to AngelaParker, for her editing, reviewing andEANM TECHNOLOGIST’S GUIDEHYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINE5
INTRODUCTIONINTRODUCTIONIntroductionAfter nearly two decades since its first edition, the Technologist’sGuide is an established tradition and a valuable product of the nuclearmedicine technologists’ community. We are all facing unprecedentedchallenges, both in our profession and in our homes. Seeing this Guidepublished in these circumstances is a tribute to our great colleagues,friends and our sponsor, who have dedicated time and other resourcesto ensure the tradition is kept alive.Every year the Tech Guide, as we all knowit, aims to bring together experts from thefield and present concise opinion andguidance on a specific topic to supportthe workforce of technologists workingin nuclear medicine. This year the topic ishybrid imaging in conventional nuclearmedicine. When choosing the themefor the Tech Guide, the Technologists’Committee had in mind the impact of nonPET hybrid imaging on nuclear medicinepractice. Moreover, SPECT-CT and the TechGuide are of similar age, so we wanted tofocus on collating conventional hybridimaging practice in one concise and upto-date guidance document.6The Tech Guide is a partnership betweenEANM committees, between physicians,scientists and technologists, and thisyear’s edition is no different. We partneredwith the Physics Committee to cover thetechnical aspects of the imaging modality,as well as with the Paediatric Committee fortheir chapter. We wanted to acknowledgethe achievements of fellow technologistslike Dr Sebastijan Rep, who is not only anambassador for the technologist’s role inquality assurance and quality control, butalso a new PhD graduate. Other chapterswere co-authored by technologists andphysicians or scientists, such as thoseon myocardial perfusion imaging andEANM TECHNOLOGIST’S GUIDEHYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINEthe contribution of hybrid imaging toradionuclide therapy.As ever, the Tech Guide has a practicalcontent, with a focus on hands-on advicefor technologists, showing the artefactsand pitfalls when imaging and the roleof the technologist in achieving highstandards of quality. The Technologists’Committee also plays an important role indefining our communication strategy withpatients in nuclear medicine, and we havetried to include this new topic in this year’sTech Guide.For us in the editorial team, publishingthis Guide is a way of saying thank youto the nuclear medicine communityfor all your passion and dedication topatient care. We wanted to showcasethe impact of our profession within thenuclear medicine community, as well asthe high standard of quality delivered bytechnologists across Europe.We trust that you will find the TechGuide enjoyable reading, and would like tothank you all for taking part in the successof this project.Marius Mada, MarieClaire Attardand Agata PietrzakEditorial teamEANM TECHNOLOGIST’S GUIDEHYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINE7
1P HYSIC S ANDR E CONSTRUC TIONM E THODS F ORS P EC T/C Tby Anne Larsson Strömvall
CHAPTER 1CHAPTER 1In scintigraphy, the distribution of an administered gamma photonemitting radiopharmaceutical in vivo is visualised using externaldetectors. The technique is sensitive and can image very small amountsof the injected radiopharmaceutical in the order of nanograms. Twodimensional images can be acquired using a stationary detector, whilethree-dimensional images can be acquired using single-photon emissioncomputed tomography (SPECT). The phrase “single photon” indicatesthat in SPECT, single photons emitted from the radionuclides are tracedto their origin, in contrast to positron emission tomography (PET), wheretwo simultaneous annihilation photons are detected by rings of detectorsin a coincidence circuit. In most cases SPECT images are used for visualinterpretation, but quantitative analyses are becoming increasinglypopular.SPECT is mostly used for diagnosticpurposes but can also be used forplanning and monitoring of radionuclidetherapies. Radionuclides used fordiagnostics are primarily chosen tohave characteristics for high-qualityimaging and low radiation dose to thepatient, including a relatively short halflife. Therapy radionuclides, on the otherhand, should provide the target organor tumours with a high dose, enough totreat the disease, and emit most energy inthe form of alpha or beta particles. Imagequality is a secondary objective, but SPECTwill of course benefit from at least somefraction of gamma photons that canbe used for imaging. The most popularradionuclide used for diagnostics is [99mTc],with a half-life of 6 h and a relatively puregamma photon emission of 140 keV. Themost common radionuclide for therapyis [131I] for treatment of thyroid diseases,with a half-life of 8 days and mostly betaradiation emission. Emitted gammaphotons of relatively high energy, 364 keV,can however be used for imaging.Hybrid imaging has revolutionisednuclear medicine with the addition ofthe structural component from X-raycomputer tomography (CT) to SPECT/CTand PET/CT, or magnetic resonance (MR)imaging to PET/MR. The first commercialintegrated SPECT/CT systems becameavailable in the late 1990s, with the releaseof the Hawkeye (GE Healthcare, WI, USA).In the beginning, this low-dose, low-cost,EANM TECHNOLOGIST’S GUIDEHYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINEand relatively slow CT provided 10 mm CTslices. Although somewhat rough, SPECT/CT image fusion then became an optionfor routine clinical work, as well as CT-basedattenuation correction. The Hawkeye waslater upgraded to a 4-slice system with 5.0mm slices, which improved image qualityand reduced CT acquisition time by afactor of 2. Nowadays there are severalmanufacturers providing fully diagnosticintegrated CTs that can help to improvenuclear medicine diagnostics and therapy.For more information on the historicaldevelopment of SPECT and SPECT/CT, awell-written review on the subject (1) canbe recommended.The SPECT/CT gantry consists of a CTbore and typically two gamma cameraheads which are mounted on the frontside. An example can be seen in Fig. 1.Figure 1: Example of SPECT/CT gantry and tableThe position of the detectors can beadjusted to a certain number of fixedpositions, for example with the detectors180 degrees (H-mode, see Fig. 1) or 90degrees (L-mode) apart. The detectors canusually also be flipped to point outwardsfrom the gantry, or can be arranged sideby side if needed. It is possible to selectwhether both detectors or only oneshould be used in the imaging protocol.For a high image resolution, it is importantthat the detectors are positioned as closeto the patient as possible. Their positioncan be automatically adjusted using bodycontour detectors mounted on the side ofthe detectors.The patient table can be adjusted inheight for loading and unloading thepatient, and to centre the patient in thescanner. Lasers can be used to help centrethe patient correctly. Special solutions withcantilevered tables have been developedfor a precise SPECT/CT registration in theaxial direction, since the two examinationsare performed sequentially with differenttable positions. The table is usuallyequipped with a low-attenuation top ofcarbon fibre, with an imaging range inthe order of 200 cm to be used for SPECTand whole-body imaging. A soft mattressand straps are used for patient comfortand to prevent movements during theexamination. The maximum permissiblepatient weight varies between scanners,and needs to be borne in mind whenexamining the heaviest patients.EANM TECHNOLOGIST’S GUIDEHYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINEPH YS ICS AN D R ECO N S TR UC TIO N ME TH O D S FOR SPEC T/C TPH YS ICS AN D R ECO N S TR UC TIO N ME TH O DS FOR SPEC T/C T10INTRODUCTION11
CHAPTER 1CHAPTER 1THE SCINTILLATION CAMERAFigure 3: Left-hand side: point source imagewith collimator. Right-hand side: point sourceimage without collimator.Figure 2: The scintillation cameraThe collimator, which can be of differenttypes, is closest to the patient and sets theacceptance angle for detection of theemitted gamma photons. The parallelhole collimator is the most commontype and consists of a lead plate withclosely packed parallel holes, usually ofhexagonal form like a honeycomb. Thelead “walls” between the holes are calledsepta. The hole diameter, hole length(collimator thickness) and septal thickness12High-resolutioncollimatorshavethinner holes compared to generalpurpose or high-sensitivity collimators,and the reduced acceptance angleleads to a smaller number of detectedphotons per unit of time and activity, i.e.lower sensitivity. Collimators optimisedfor higher energies, known as mediumenergy or high-energy collimators,have thicker septa to prevent septalpenetration, which otherwise leads toreduced contrast and star patterns aroundhotspots in the image.Another relatively common collimator isthe multiple-pinhole collimator. It consistsEANM TECHNOLOGIST’S GUIDEHYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINEof a series of lead cones with a small holeat the apex, facing the imaged object. Withthese pinholes, the size of the image willdepend on the distance from the objectto the pinhole, which is not the case forparallel-hole collimators. The multiplepinhole collimator is convenient whenthe imaged objects are small, for examplesmall animals or small organs like the heartor the thyroid, since these objects can bemagnified to produce a higher resolution.There are also other types of collimators, forexample fan-beam, cone-beam and slanthole collimators. For more information thecollimator review by Van Audenhaege etal. (3) is recommended.The detector material in the scintillationcamera is typically a sodium-iodide (NaI)crystal doped with a small amount ofthallium (Tl), which is needed in order forthe crystal to generate scintillation light.It is coated with a thin protective layeron the front and edges to protect fromoutside light and moisture. A scintillationcamera for diagnostic purposes usuallyhas a crystal thickness of about 1 cm (3/8inches), whereas a scintillation cameraused mainly for radionuclides emittinghigher energies may need a thicker crystal,for example 1.6 cm (5/8 inches) or even upto 2.5 cm (1 inch) in order to capture themajority of the photons. When a gammaphoton interacts in the crystal, lightphotons are created, and their number isproportional to the energy deposited. Therear side of the crystal is optically coupledto a light guide made of glass, whichdirects the light onto an array of closelypacked photomultiplier tubes (PM tubes).The PM tubes are relatively large, a fewcentimetres wide, and there can be 50–70of them in a detector head of conventionalsize. The PM tubes first convert the lightphotons into electrons and then massivelyamplify their number. This results inmeasurable electrical pulses from thosePM tubes that are hit by the light photons.The pulses are then processed to giveinformation on the location of the gammaphoton interaction in X and Y directionand the energy deposited in the crystal.Due to non-linearities, correction tablesare used to improve the accuracy of bothposition and energy, and a uniformitymatrix is used to correct for irregularitiesin detector response. The interactions inthe crystal that are to contribute to theimage are sorted out by logical processes,comparing the measured energy with theenergy window settings.PH YS ICS AN D R ECO N S TR UC TIO N ME TH O D S FOR SPEC T/C TPH YS ICS AN D R ECO N S TR UC TIO N ME TH O DS FOR SPEC T/C TThe traditional detector used for SPECTimaging is known as a scintillation cameraor a gamma camera. It was developed inthe late 1950s by Hal Anger (2) and hasbeen a standard imaging device in nuclearmedicine for a long time. The majorcomponents of the scintillation cameratoday are in many cases similar to when itwas invented, but its performance has ofcourse improved over the years, especiallythrough the introduction of digitalelectronics and multiple head systems. Aschematic diagram of the intersection of ascintillation camera detector can be seenin Fig. 2.depend on the resolution/sensitivityand the photon energy range for whichthe collimator is optimised. Collimatorsare crucial for identifying the point ofemission. To illustrate this, an image ofa point source acquired both with andwithout the collimator on can be seen inFig. 3.THE CZT CAMERAThe NaI scintillation crystal is a sensitivedetector material with many advantageswhich has been in use for several decades.Recently, however, CZT-based gammacameras have become increasinglypopular. CZT was first introduced in pre-EANM TECHNOLOGIST’S GUIDEHYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINE13
CHAPTER 1CHAPTER 1a few centimetres wide, it is easier toget a tight orbit around the patient’shead. The removal of the PM tubes isalso advantageous for dedicated cardiaccameras, which incorporate severaldetectors pointing at the heart fromdifferent directions, allowing stationarySPECT acquisition. This design would bevery difficult to achieve if bulky PM tubeshad to be connected to the detectors.Another advantage with semiconductor detectors is energy resolution,which is a measure of uncertainty of themeasured gamma photon energy. In aNaI-based system the energy resolutionis usually in the order of 9–10% for 140keV (calculated as the full width at halfmaximum of the photopeak divided bythe peak energy), but with a CZT camerait is usually better. Values in the order of3% have been reported for pre-clinicalsystems, whereas many clinical systemsseem to be closer to 6% in terms of energyresolution. A small percentage value (highenergy resolution) is positive, since itmeans that a tighter energy window canbe used when collecting the primaryphotons. Less scattered photons will beregistered within the energy window,which means higher contrast and lessneed for scatter correction. The highenergy resolution is also a key factor insome cases of dual- isotope imaging. Ifsimultaneous imaging of [99mTc] and [123I]is warranted (photon energy: 140 and 159EANM TECHNOLOGIST’S GUIDEHYBRID IMAGING IN CONVENTIONAL NUCLEAR MEDICINEkeV respectively) the peaks will be easierto separate with a CZT system than with aconventional one.In contrast to NaI-based cameras, CZTcameras can be manufactured as pixelatedsystems, meaning that the detectorsurface is composed of a high number ofsmall detectors. Each detector is mappedto a corresponding pixel in the image. Thishas been reported to be advantageous interms of resolution and contrast-to-noise,but it can also have disadvantages. For aparallel-hole collimator, the collimatorholes need to be matched exactly to thedetector locations, and this means lessflexibility when it comes to resolution/sensitivity considerations. If the systemincludes a fixed collimator optimised forlow-energy imaging, it is also difficultto perform imaging with radionuclidesemitting higher energies such as [111In],[177Lu] or [131I].COMPUTED TOMOGRAPHY (CT)CT is a technique which originated in theearly 1970s, and its developers, Cormackand Hounsfield, were awarded the NobelPrize in 1979. It is not difficult to imaginewhat the introduction of 3D imagingmeant for radiology at the time, and theexplosion in research and developmentthat followed. In CT, a motorised X-raytube rotates rapidly around the patientin a circular orbit, while the patient tablemoves through the gantry. The detectorson the opposite side of the tube measurethe X-ray photons that are not attenuatedin the patient. Collimators are used tolimit the X-ray field to the detectors,defining the slice thickness. Bowtie filtersare needed to shape the X-ray beam byremoving more of the low-energy photonsfrom the peripheral parts of the field,thereby reducing the radiation dose tothe patient. The signals from the detectorsare converted into digital information,and the tomographic images can then becalculated from the measured projections.A complete scan can be acquired in a justa few seconds.CT technology has evolved rapidlyduring the last decades, and advancedmulti-slice models have been developedin order to improve image quality, reducescanning times, reduce the dose to thepatient, and freeze cardiac and respiratorymotion. Top-of-the-range models are ableto acquire up to 640 slices per rotationwith a rotation time of about 0.3 s. Dualene
in nuclear medicine. This year the topic is hybrid imaging in conventional nuclear medicine. When choosing the theme for the Tech Guide, the Technologists’ Committee had in mind the impact of non-PET hybrid imaging on nuclear medicine practice. Moreover, SPECT-CT and the Tech Guide are of similar age, so we wanted to
nuclear imaging. PET/CT scanners perform a significant role in contemporary nuclear imaging as an outcome of their hybrid existence. A Hybrid PET/CT scanner can show the information of the image by merging metabolic imaging (PET) and morphological imaging with computed tomography (CT).1 Phantom is commonly used as a PET/CT scanner validation
1. Medical imaging coordinate naming 2. X-ray medical imaging Projected X-ray imaging Computed tomography (CT) with X-rays 3. Nuclear medical imaging 4. Magnetic resonance imaging (MRI) 5. (Ultrasound imaging covered in previous lecture) Slide 3: Medical imaging coordinates The anatomical terms of location Superior / inferior, left .
Nuclear Chemistry What we will learn: Nature of nuclear reactions Nuclear stability Nuclear radioactivity Nuclear transmutation Nuclear fission Nuclear fusion Uses of isotopes Biological effects of radiation. GCh23-2 Nuclear Reactions Reactions involving changes in nucleus Particle Symbol Mass Charge
Guide for Nuclear Medicine NUCLEAR REGULATORY COMMISSION REGULATION OF NUCLEAR MEDICINE. Jeffry A. Siegel, PhD Society of Nuclear Medicine 1850 Samuel Morse Drive Reston, Virginia 20190 www.snm.org Diagnostic Nuclear Medicine Guide for NUCLEAR REGULATORY COMMISSION REGULATION OF NUCLEAR MEDICINE. Abstract This reference manual is designed to assist nuclear medicine professionals in .
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Head to Toe Imaging Conference 34th Annual Morton A. Bosniak The Department of Radiology Presents: New York Hilton Midtown December 14–18, 2015 Monday, Dec. 14 Abdominal Imaging & Emergency Imaging Tuesday, Dec. 15 Thoracic Imaging & Cardiac Imaging Wednesday, Dec. 16 Neuroradiology & Pediatric Imaging Thursday, Dec. 17 Musculoskeletal Imaging & Interventional
BIBLIOGRAPHY Physics for Medical Imaging P. Allisy-Roberts, J. Williams – Farr’s Physics for Medical Imaging Radiological Physics P. Dendy, B. Heaton – Physics for Radiologists Medical Imaging J. Bushberg et al – The Essential Physics of Medical Imaging S. Webb – The Physics of Medical Imaging Nuclear Medicine
In the midst of Michel’s awakening to the sensuous, sensual existence, to the Dionysian world in nature and himself, he observes: [Marceline] led the way along a path so odd that I have never in any country seen its like. It meanders indolently between two fairly high mud walls; the shape of the gardens they enclose directs it leisurely course; sometimes it winds; sometimes it is broken; a .
