My name is Dr. James Case, and this is Part 2, Instrumentation Module 4, Hybrid Imaging and PET-CT. Here are my disclosures for this presentation. The learning objectives of this presentation are first to understand hybrid imaging and its uses for attenuation correction, examine CT-related artifacts, and review the mitigation strategies. We're going to understand the strategies for acquiring CT data for assessing coronary calcium, and then we're going to look at strategies for maximizing image quality while minimizing radiation dose. PET-CT scanners in hybrid imaging in general is a combination of two different types of scanners. The first scanner in hybrid imaging that we're going to consider is a PET scanner. As you can see here, here's a PET scanner with each one of the individual modules of the scanner wrapped around the center of the scanner. The second part, the other side of the scanner, is the CT portion of the scanner. You can see it's been pulled apart here, and we can see the CT. So a hybrid scanner takes the CT for anatomical assessment along with the PET part of it for physiologic assessment and combines it together into a single piece of instrumentation capable of simultaneously assessing physiology and anatomy in a single data set. There are advantages and disadvantages to hybrid imaging. The advantage of hybrid imaging is it allows for higher CT scanning times when compared to line source attenuation correction. We have a higher count transmission studies. Then finally, we have the CT as an added piece of instrumentation to our studies that allows us to assess the presence and existence of coronary calcium. On newer PET-CT systems, we can also have a fully functional cardiac CT system capable of doing coronary CTA, runoff studies, et cetera. The other thing that's also a value of hybrid is the ability to use a scanner for multiple uses beyond just cardiac uses. Many laboratories use partnerships between radiology, oncology, and neurology to give them the ability to acquire more advanced instrumentation by sharing the costs associated with ownership of these types of machines. Some of the drawbacks to hybrid imaging are they do come with a higher radiation dose when just doing attenuation correction than CT. It does have its own unique motion artifacts associated with breath holding and misregistration. There also can be artifacts associated with implanted devices. And then finally, you may also have regulatory requirements in your jurisdiction for technologist and physician credentialing. So here are two examples of a dedicated PET machine and PET-CT, which would be used for hybrid imaging. Above, we have an example of a dedicated PET-CT system, or I mean a dedicated PET system. Inside of this, there is either a rod source or line source or point source of activity, which rotates around the patient for collecting transmission data. And that is the source that's used. Now, the nice thing about these is it's a sealed radiation source. It's on a smaller footprint, these systems. They're only available on the refurbished market today. They're considerably lower expense. Their downside is that they have long transmission scans. And though it's not written here, we don't have the added information of the CT. Now, for hybrid PET-CT, we typically use, and here we have a scanner where the front part facing us is the CT. And back in the back is the PET portion of it. Their larger footprint, the scanners tend to be more expensive than their dedicated counterparts. They do have very short transmission time. But because of the nature of PET-CT, they are more complicated to get the transmission scan done correctly as opposed to the line source. So there are some downsides of the PET-CT. However, the added information in most situations outweighs the value, the potential drawbacks of hybrid CT. Now, attenuation, when we're talking about X-ray imaging, really falls into three different types. The first type is something called rayless scattering. And that is a bit like the, it's a similar concept to Compton scattering. Rayless scattering is seen at lower energies where it scatters off of an electron but doesn't ionize the atom. Where Compton scatters at a higher energy and ionizes the, kicks the electron out of the atomic shell and sets it free. So these are the two types of attenuation we see in X-ray. And then finally, we also have something called photoelectric effect. Where the photoelectric effect is where the energy of the photon is completely absorbed by the atom without ionizing the atom. So these are our three different types of interactions that X-rays can have with the medium. Now the production of X-rays is done in something called an X-ray tube. Now the X-ray tube, the way those work is we supply electrons through a cathode. And then by creating an electronic potential between a cathode and an anode, the electrons can be accelerated across a space and strike the surface of the anode. So as those electrons travel across and hit that anode, they decelerate. And as they decelerate, they give off that kinetic energy in the form of something called Bremsstrahlung radiation. Literally translates into breaking radiation. And when it does that, we get a broad spectrum of photons being emitted from that X-ray tube. And it's those X-rays that we utilize in an X-ray tube to create an X-ray image. So the X-rays created by the X-ray tube fall under the spectrum down here in gray. So it's a broad set of energy starting at the highest energy, which is the maximum energy of the electron striking the plate. And then it descends down to a peak in a continuous fashion and then drops out. So X-rays are not monochromatic like we have with technetium or even positron energy. They cover across a broad range, along with a few spikes in the middle of something called characteristic X-rays. So this is in contrast to technetium, which is a monoenergetic photon that's emitted at 140 KeV. And then 511, which is from the annihilation photons. Now, the counterparts in PET and SPECT also have something called a Compton edge, which as we can see down in here, are photons which are scattered within the medium off of electrons and create a lower energy cloud of photons. So you can see here the photons at the 511 get scattered by the medium and form this long, broad Compton edge. So an X-ray tube has two settings that are used for determining the type of X-ray beam that's created. The first of which is the Kbp, and that determines the kinetic energy of the electrons that are crossing between the cathode and the anode. And then there's the Mas, and that's the number of electrons that are being pushed from the cathode to the anode. Now, the Kbp, the higher the Kbp, the more high energy photons, the amount of energy each individual photon is going to have that's created. And as we have higher energy photons, we have more penetrance through the patient. So a higher beam, a harder beam means that we can get more penetration through the patient. On the other hand, we have Mas. The higher number of counts we get, the better signal-to-noise we get. So in some sense, both Kbp and Mas can have impacts on the final image, but they work in different ways. The way we create a tomographic image in CT is to take the X-ray tube and rotate it around the patient in a very rapid fashion, pushing the X-rays through the patient and then being received in a detector on the other side of the patient. Now, this array of detector and X-ray tube will go across, will circle around the patient very rapidly. Scanners can get around the patient as fast as three times a second. They can cover the entire 360 degrees around the patient. And this gives us a very rapid projection of the cyanogram, the cyanogram being the mapping of the patient's anatomy, projection anatomy, that will be used for creating the reconstruction. Now we can acquire those cyanograms in two different ways. The first scanners that were created for CT used a single combination of a detector. And an X-ray tube. And it would take a long time for those two orbiting one another to create an entire volume of a patient. Modern day multi detector CT scanners will have several different slices, upwards of 256 individual slices. The more slices you have, the more volume you can cover with each pass of the patient. And the more you're able to stop the heart's motion in time. So there are two different scanning strategies that are in use. The first is sequential scanning or step and shoot. And the way that these work is that the patient will get scanned. The CT scanner will make one pass around the patient. The patient will be moved and then they'll be scanned again, move, scan again. The second way of doing the acquisition is spiral scanning. In which case the scanner is left spinning and the patient is fed through the system. And the volume is acquired in a continuous fashion. You get an idea of the type of G-forces. If we have a rotation of one rotation per second on a typical scanner, that would be the equivalent of four G's of force wanting to fling all of that CT hardware apart. The faster we go, the more G-forces we get. So if we go from one rotation a second to half a rotation a second, we go from four G's to 16 G's. Now if we go from half to a third, we go from 16 G's to 37 G's. So very quickly the engineering challenge of keeping a precision piece of equipment together in this very high G environment becomes difficult. But it's necessary in order to stop the motion of the heart in time and allow us to image the small coronaries in their place. So what are the capabilities of the different systems on the market today? They really fall into three broad categories. The first of which is the low slice systems, the four and the six slice systems that are out there. They typically have an in-plane resolution of about a millimeter and a plane-to-plane resolution of about three and a half. These are only going to be helpful in doing attenuation correction. Now if you go up to the 16 slice machines, in-plane resolution gets nearly isotropic. So 0.75 millimeter in-plane resolution, 1.0 is kind of typical numbers. And that's good for attenuation correction, calcium, and non-coronary CTA. Now as we get higher up, 64, 128, and 256, we get to truly isotropic and then we can consider virtually every type of CT procedures. That is a full-fledged, dedicated CT type of machine when we're getting at that 64 slice and higher type of environment. So one of the challenges that we have in using hybrid imaging with PET is that the primary goal of PET-CT imaging is to acquire a high-quality PET study with attenuation correction. Most of the time the lion's share of the clinical information we get comes from the PET and it would be unacceptable to be able to have a CT acquisition with nearly, if not more, radiation dose than the PET. So there's several different ways we can reduce the radiation from the CT. The most direct way is reducing the MAS. So the number of counts that are being pushed through the system. MAS on the order of anything greater than about 60, 70 MAS, that is a diagnostic level of radiation and should not be used for attenuation correction. Now there are dose reduction techniques that can give you equivalent amounts of studies at a lower radiation dose. But in those cases, consult with your CT manufacturers, field service engineers to be able to establish what is the best way to minimize dose when using those dose reduction techniques. The second approach you can use to reduce dose is to use the appropriate KVP, not making the KVP excessively hard for the task of doing attenuation correction. Another thing to do is to minimize the amount of slice, so increasing the feed of the patient through the tube to be able to get the study as quickly as possible. Another thing that can be used is varying the tube current. This really only applies to CTA and coronary calcium scoring. But each study should always be considered in terms of risk benefit model for determining dosage. Attenuation correction for PET or SPECT, are we doing calcium screening, do we want to do CT angiography, etc. Anytime we turn on the CT scanner, you need to make sure that you're applying an appropriate level of radiation based on the information that's needed for the test. Now, one of the interesting things about doing PET-CT is that we have two very different types of photons that we need to provide radiation protection from. The first of which are the x-rays, and most of them are going to have less than 120 KeV. And those are very easily blocked using lead. And when we apply CT, the very nice thing about the CT part of it and shielding is that we apply our radiation dose, and then as soon as we turn the x-ray tube off, the radiation is gone, so doing things like entering the room are going to be safe once the scanner is in its off mode. So the factors again that we can use to manage the radiation dose with computed tomography is the scanner type, x-ray output parameters, KBP and MAS, beam collimation and shielding, making sure we're only irradiating the regions that we're after, pitch, so that's the speed at which we can move the patient through the study, not exceeding the x-axis scan range, so that we're not scanning any further than we need to, and then tube modulation, in those cases where we need easy gigating on it, and then also use an appropriate dose for larger patients. So I'm going to leave this for learners to go into more detail, but fundamentally the four major parameters that are going to determine PET-CT image quality are going to be KBP, as discussed earlier, that determines the hardness of the beam, increased KBP reduces image contrast, but improves beam penetration, MAS improves signals of noise, pitch reduces breath hold time, reduces breath hold time and reduces patient dose, but can introduce artifacts if there are problems with patient motion during the study, field of view should only include the organ of interest, for clinical studies like calcium scoring, we try and keep that around just the heart, and for CT attenuation correction, it can be opened up, but the dosages have to be lowered as a result. We also, when we're considering radiation dose and hybrid imaging, we need to also consider the dose to the staff, and in the traditional way of thinking of radiation protection, we use time, distance and shielding. With SPECT, distance and dosage become very important in terms of managing the patient and worker exposure. Now with CT systems, shielding, time and distance are all effective, but probably the most effective for CT is going to be shielding, because the lower energy photons are easily absorbed by lead, and also time, since the scanner is only on for a very short period of time. Now with PET systems, what we find out is the high energy 511 KEB system, KEB photons are not well absorbed by lead, so we have to use other tools at our disposal. So how helpful is shielding? With CT, it's very helpful. You can see CT as a lead is very effective. With a millimeter of lead, you can see that only a hundredth of the CT beam remains after passing through a millimeter of lead. But interestingly, if we look at how effective lead is in blocking 511 KEBs, you can see that same millimeter only reduces by about 12% the amount of photons in the beam. You have to get to almost 4 millimeters of lead to reduce it by a factor of 2. The CT Quality Control Program, there's one that's used for both CT, just like we have for PET. It uses a specialized phantom. You can see that in the in the two images there and The most common is a four chamber phantom and What they do is they look at high and low contrast resolution image uniformity image noise slice thickness light alignment light accuracy Then finally what we have to do is CT number, which is the balance point between zero Hounsfield units, which is by definition the the attenuation coefficient for water In CT and as you can see this four chamber view has the four different Pieces of it all of which running a different sort of experiment on the system to confirm that it's working. Well Now the way in which we can use CT and Transmission computed to Margaret to create an image is what we do is we take the loss of counts from a source Through the patient and see what's received at the detector now these equations here and I'm not really going to go into What they mean they but what they're saying is that? We can make a measurement in the drop in counts now in transmission commuted tomography, the only thing we really know We really need to know is how much is lost From the point of emission to the point of reception the way we do that is we compare an image without the object in the way With the object in the way and that can then be used to to create to create our Reconstruction the challenges for CT attenuation correction are The x-rays from the tube extend over a wide range of energies. It's a continuous spectrum not monochromatic like technetium and and 511's The CT image is often acquired over a single respiratory cycle making Matching the the CT image with the emission image more difficult Even in a low-dose configuration CT based attenuation correction has a higher radiation dose than dedicated then finally it's susceptible to artifact introduced from metal artifact from implanted metal devices Now the units that are used in In CT are different than PET and SPECT PET and SPECT cap units are based on The counts that are received by the imaging system represented it represented as as counts or a measurement of dose per unit volume Like megabeckel per CC or something like that Now with CT what we're going to do for dose is we create a fictitious relationship between the attenuation coefficients based on Something called a Hounsfield unit where we define zero at the zero point as That of that of water and Then we go and set the second part of it at the but the edge of it for air at at minus 1024 so we cover this entire range for Hounsfield units All the way up as high as it will go now The trouble is is that when we try and convert CT Hounsfield units from? from Hounsfield units and then try and use it as an attenuation map We have to create a mapping between our attenuation Coefficients and the CT number the most common one used is something called a bilinear relationship And what the bilinear relationship is is two different types of relationships For those densities which are less than water and those densities that are greater than water Now the protocols that are used in hybrid imaging are Are typically you have two families one is for those patients with no known CAD In which case the patient may also be imaged with a coronary calcium study followed by a CT attenuation map study and then our regular perfusion study and Then for patients with no CAD the added value of the coronary calcium study is minimal And so it's typically left out. And so we have a more abbreviated study So this that the first stage of a PET CT study is to acquire a topogram now this topogram is A regular two-dimensional scan which is scanned over a larger area of the chest And we use that this to identify the area of interest in which we can find the heart you can see the area in the pink here as the is the area of the single bed position that we're going to use for our PET study Once we have that lined up we can go ahead and do the CT scan Now the second stage is the CT for attenuation correction So in that in that part of the study We acquired the CT study and then what is done with that CT study for attenuation correction is we dumb that down Make it blurrier and remove the contrast using that bilinear relationship to create a fictitious Representation of the CT map as if it were a line source image interestingly enough, and then we create a Virtual forward projection as if it was a line source unprocessed raw Sinogram Then one of the neat things about PET to do attenuation correction We merely have to take the transmission Sinogram as if it was just a line source Transmission line Sinogram multiply it times the emission Sinogram to create attenuation corrected Sinograms, so there is no need to build the attenuation correction into the Into the reconstruction problem we can just simply multiply out the the attenuation from the final images You Now some of the considerations that we have with with PET CT is in the breathing and the breathing protocol what is typically done is We have to be able to capture a CT image That we're going to use for attenuation correction The trouble is is that the PET studies are acquired in a free breathe mode over several minutes Whereas the CT images are done within a single respiratory cycle typically now there are protocols out there which which allow a user to acquire a CT over several Several breathing cycles and thereby give you a good average which is very similar to what's done in in conventional PET The other other protocols that are used Include either an end expiration breath hold or for shallow free breathe protocols All of these protocols have been demonstrated to produce high quality PET CT studies However, it is important to know the capabilities of your system and to train your patient and staff on How to do these correctly You So PET CT the single biggest source of artifact in PET CT is motion, but there are several different families of motion artifact in PET CT there's misregistration, which is which is where the transmission data set is in a different place than the emission data set and this can create a Visible artifact in the image the second type of artifact that's seen is a breath hold artifact where the diaphragm is Two different places. So for instance here and here during the emission study or during the transmission study and this creates an inaccurate representation of the attenuation map and thereby introduces artifact in the final attenuation corrected image and Then finally there's intrascan motion intrascan motion is where the patient motion is confined exclusively into the emission study Misregistration and intrascan Motion are covered in other modules I'm going to focus on the breathing protocol since that's exclusive to hybrid imaging Breathing artifacts can happen when the diaphragm is captured at different places as the CT scanner Traverses the volume now. There are a couple of different approaches that can be used to to deal with the difference in breathing between the free-breathe PET study and and the slow-breathe shallow-breathe or breath-holds of CT imaging one technique which is the slow pitch free-breathe allows the scanner to cover the volume at a slow pace catching the diaphragm in multiple positions through as it crosses and then use the software to recreate a Diaphragm averaged The diaphragm averaged CT map for attenuation correction Another approach is a shallow free-breathe where the patient is allowed to breathe normally but but only in a shallow fashion to minimize the motion of The of the diaphragm and then finally there's an in expiration breath hold Which is where the patient is asked to breathe in breathe out breathe in breathe out hold And in which in that case the patient is breathing Is is that a breath hold but it's at the expiration so reducing the overinflation and distortion of the shape of the of the lungs all of these protocols can be done successfully and And produce high quality results. They also have limitations. So before implementing any one of these three approaches you you should work with your manufacturer to make sure that you understand what's necessary to implement them well and And then practice them with the patient prior to to image acquisition The the next unique artifact that we see in in In hybrid imaging is something caused by beam hardening beam hardening happens when the x-ray tube puts out its broad spectrum of photons and what happens is is that the lower energy part of that of that Coherent of that continuous Energy spectrum of photons is that the lower energy photons are picked off first leaving only the higher energy ones behind and Therefore what that happens is is that the the efficiency by which the beam is attenuated? Stops being continuous and then becomes depth and material dependence. So there's a nonlinear relationship between absorption attenuation and in the energy of the beam Now this can have significant impacts on on the CT image quality when metal is present in the in the images So in this particular image We have an implanted device That's that's introducing an artifact along the right side of the heart And if we look at the impact that that has on the images, you can see a hot spot Infra septally that when we apply metal artifact correction goes away most modern hybrid systems today have a metal artifact correction algorithm and in most cases given the number of patients that have implanted medical medical devices Shock coils ICDs all sorts of different metal within the chest in most cases metal artifact correction metal artifact correction has little downside on patients who don't have an implanted device and can help tremendously on those that do Recently Recently there has been Guidelines finally released by the American Society of nuclear cardiology a APM SCCT and the SNM on what to do with the clinical information contained within the CT data sets Now what we can see when we look at the images is very quickly we can recognize we can we can recognize the That there's a lot of information beyond just being The information that's used for attenuation correction in this particular study you can see it's non-gated For sliced PET CT system. So so not a particularly advanced CT system, but you can see right away There's a lot of information in there. We have pericardial thickening a pleural effusion coronary calcium all contained within a non-gated non-breathable for sliced PET CT system so there's a tremendous amount of information contained with these images and The article mentioned on the previous slide helps us know what we're supposed to do with that information So if we go beyond just doing attenuation correction to looking at the difference between CTAC scans and coronary calcium scans, we're going to use higher higher dosages and diagnostic quality settings so low dose limited diagnostic quality That's going to mean we're going to have thicker slices lower Doses, we're not going to gate We're going to use a spiral scan and we're going to incorporate the entire field of view now if we transition to try to do Quantitative coronary calcium. We have a diagnostic quality study. We use a breath hold every time We're going to use MAS higher MAS oftentimes higher KVP We're going to have a smaller field of view to concentrate that higher radiation Into a smaller field of view to reduce patient dose we're going to ECG gate and then we're going to apply step and shoot is the typical way in which it's done and for those reasons calcium scoring Should not be done on a CTAC scan. So it's very specific a calcium scoring exam From the acquisition standpoint So it is not recommended that Quantitative calcium assessment be performed on CTAC scans in most cases CTAC scans for calcium are visually assessed in terms of none mild moderate severe or some sort of scale like that But in terms of quantitative assessment of calcium a true diagnostic study needs to be acquired for that So What are the guidelines say in terms of minimum Scanner requirements for doing for doing calcium scoring you need at least eight slices The acquisition needs to be at least two and a half to three millimeters in slice thickness 120 KVP and Appropriate MAS to get a good high quality study. It can be reconstructed Using filter backprojection or iterative it needs to be gated and then preferably the diagnostic frame used for quantitation So, what is this added information that we get from the calcium assessment Though there's a lot of it. There's The absence of coronary calcium predicts a low risk of obstructive CAD It adds important clinical information patients with a non ischemic mild cardioperfusion study and that's where the recommendation that it be done in patients with no known CAD and And it doesn't add much the flip side of that is it doesn't add much value in patients with known CAD Coronary calcium may also aid in in the assessment of the perfusion study and also Interestingly the visual assessment of coronary calcium Alone, even though these are lower dose non gated studies still adds a tremendous amount of useful information Okay, when processing the PET CT, we need to ensure that all the pre reconstruction artifacts are turned on That includes prompt gamma correction metal artifact correction in randoms and scatter correction So all these should be turned on when the processing is performed Inspect all the images for breathing artifact if breathing is present consider using an alternate scan. That's one of the really neat things about about these studies is that if we have a Both a stress CT and a rest CT We can switch out which CT we want to use for the attenuation correction Correct the misregistration using the best CT available reconstruct our Perfusion gated dynamic studies with the misregistration correction If you need to do a misregistration correction, make sure all three studies have that misregistration correction applied In order to assess the misregistration and PET CT The first thing that we need to do is we need to look at the entire volume From top to bottom and left to right you can look at it in the coronal view sagittal view or The transaxial view and what we want to do is we want to assess if the heart Is out the lung field and when that happens, we need to move it back into a correct position not too far But we need to make sure that the heart is not resting out in the lung field So you can see in this particular view. Let's brighten that up a little The heart is on the lung field and we can see all of these overlapping pixels Within the image the white being the overlapping pixels the gray being the being the lung field and when they overlap It will reduce the counts within the image and produce imaging artifacts So looking at if we process with that amount of offset you can see there's a significant defect anteriorly and laterally In the stress image, but you can see the resting image. There's so much misregistration artifact that the images are almost uninterpretable Now when we go ahead and correct for that misregistration artifact What we're going to do is we're going to shift the transmission data and the emission data relative to one another To remove these offset artifacts so you can see there's a lot of artifact there and A little bit not as much up in the stress. So we're going to shift the offsets relative to one another you can see At this point. We don't want to overdo it if we shift too far to the down and to the right It will introduce new artifacts. So it's not enough to move it out of the lungs You need to move it by the correct amount. There we go. That's that looks pretty good And with that amount of Misregistration artifact you can see the misregistration artifacts have gone away and And the images look considerably better So when we go through and we evaluate these studies Hybrid PET-CT studies we have to assess whether or not we have a good Registration between the stress and the rest we check for the presence of any metal artifacts We check for any breathing artifacts both on the stress and the rest and we inspect for calcifications and secondary findings So here the first step is we look at the overlays and the overlays you can see here the seat in this particular study The heart is out of the lung field and not by too much but by a good amount. So that's that's acceptable We also have to do that for the rest it's not enough to look at it for just the rest the rest also Looks very good We also inspect the calcium and you can see there there's a small amount of calcium But otherwise, it's a high-quality study. So when we do this quality assessment, before we even dive into interpreting the study, we know this is a high-quality scan. There's no apparent misregistration. There's a minimal amount of intra-scan motion. It's a high-quality CT study patient with a small amount of coronary calcium. So when we go ahead and look at the study itself, we can see it has normal perfusion pattern along with normal gating, and finally, a normal blood flow reserve. So the conclusion of this particular study is it's a high-quality scan with no misregistration, no metal artifacts, CT of very high quality. There's some coronary calcium, normal perfusion, normal gating, and normal blood flow. So this is the way in which we extract information by using PET-CT, and the CT part of the study did several things for us. It gave us information that the patient – it gave us the attenuation correction. It also contributed to the quantitation of the blood flow as well as added information about the presence of coronary calcium. So in that way, in three different ways, the fact that we did a hybrid study improved the final interpretation of this case. Now there's some other stuff that is available that we won't go into here that can be done with PET-CT, and I'd like to draw your attention to these ASNIC practice points on viability, sarcoid, and inflammation, all of which are PET-CT protocols, and encourage you to take a look at them as additional applications of hybrid imaging in PET. So finally, in conclusion, hybrid imaging provides essential information for myocardial perfusion PET imaging. First and foremost, it allows us to do attenuation correction. It also allows for both the visual and, if done using a diagnostic study, a quantitative assessment of coronary calcium, and the CT acquisition can also be used for identifying extracardiac findings. The quality control program is also very different from what we have in SPECT and dedicated PET. The CT portion, just like the PET portion, has to be looked at every single day. The processing for common artifacts is important, if not more important, because of the higher resolution and the complication between combining two different modalities. The unique problems of hybrid imaging must also be addressed, such as metal artifact and breath holding. But despite these challenges that were presented in this presentation, PET-CT offers a new dimension in evaluating patients with known or suspected coronary disease. Thank you for your attention to this module of the PET-CT, the PET curriculum. Thank you.

Cardiac Pet Curriculum

instrumentation

hybrid imaging

Pet CT

attenuation correction

CT-related artifacts

coronary calcium

image quality

PET-CT

CT data acquisition strategies

Coronary calcium assessment

Radiation dose management

Artifact corrections

Quality control programs