Name: A Basic Positron Emission Tomography System Constructed to Locate a Radioactive Source in a Bi-dimensional Space (Video) | JoVE Journal
Uploaded: 2016-02-01T13:00:00.000+00:00
Duration: 14 min 19 s
Description: Learn to construct a basic PET system using photo multiplier tubes and plastic scintillators for medical physics education. This hands-on method helps students understand positron emission tomography principles through practical experience.

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5 minutes

We are very grateful for the financial support of the Physics Department of CINVESTAV. We also want to thank our technician Marcos Fontaine Sanchez for his remarkable assistance with the set up. Thanks a lot to Sarah LaPointe for reviewing the English-language of this document.

1. Preparation of the PET Setup
<ol>
	<li>Prepare the PMT&#39;s coupled with plastic scintillator pieces. Depending on the kind of PMT (size, shape of the photocathode) build an adequate scintillator piece to fit with the photocathode of the PMT.
	<ol>
		<li>Wrap the scintillator pieces with black tape. Leave one side uncovered, as it will be coupled with the PMT light entrance. 
		NOTE: It is important that these pieces are previously polished to avoid light accumulation losses.</li>
	</ol>
	</li>
	<li>Clean the PMT light entrance with alcohol (commercial alcohol concentration of 70%) then apply optical grease to it and the scintillator&#39;s uncovered face. Coupled the PMT face with the scintillator and wrap them with more black tape.
	<ol>
		<li>Connect the PMT to the source voltage (a cable is included for every PMT, in this case bias 14 V bias and 0.5 V for voltage control). Identify the signals coming from the PMT by connecting the PMT signal cable to a standard digital oscilloscope channel (a signal cable is also included for every PMT). Observe the variations in amplitude of the signals when turning on/off the light in the lab, to verify there are no light losses. Repeat this step for each of the four detectors, where a detector means scintillator plus PMT.</li>
	</ol>
	</li>
	<li>Build a coincidence system by placing the scintillator part of one detector above the corresponding part of another detector. Put two NIM (Nuclear Instrument Module) instruments called discriminator and logic unit modules in a NIM crate.</li>
	<li>Connect the output signals from the detectors to the inputs of a discriminator module. Use a logic unit in the AND mode, by selecting this logic case in the logic unit front panel. Connect the two discriminator outputs in the logic unit inputs. 
	NOTE: AND is a logical operation that selects when two square signals arrive at the same time or in coincidence.</li>
	<li>Connect the logic unit output signal in a scaler module (which counts digital signals) to count the events (created by the cosmic rays hitting in coincidence both detectors).</li>
</ol>
2. Acquiring Signals with PET
<ol>
	<li>Place both detectors in the opposite corners of the square area defined before, so they face each other, and are 20 cm apart, and do the same exercise as 1.4 and 1.5, but this time, instead of using cosmic rays (cosmic rays served as a provisional natural radioactive source), use the Na-22 radiation source.
	<ol>
		<li>Place the radioactive source in a middle distance between both detectors and make data acquisition through the scaler module. The system set up and the schematic arrangement of the logic block used to obtain a coincidence can be seen in Figures 1, 2, and 3.</li>
	</ol>
	</li>
	<li>Measure the time difference of the arriving signals by connecting the two discriminate PMT&#39;s outputs and the coincidence output in the oscilloscope. Each of the three signals goes to an oscilloscope input; there will be three square signals in the oscilloscope screen. With the horizontal scale (time scale) measure the time difference of the two discriminate signals. 
	NOTE: When the radioactive source is directly in the middle between both detectors there will be little or no separation or time difference between the square discriminate signals on average, and when the radioactive source is out of the center and close to one of the PMT then there will be time difference on average.</li>
	<li>Send these timing signals to one of the eight channels of the CAMAC (Computer Automated Measurement And Control) TDC (Time to Digital Converter) module. To do this, connect the output of logic AND to the TDC input call &#34;START&#34; then connect the detector discriminate outputs to the TDC inputs which are called &#34;STOP&#34;. The AND signal has to be delayed through a Delay Module by some nanoseconds in order for this signal to arrive before the other two STOP signals (see Figure 4).</li>
	<li>Calibrate the TDC counting units vs. time showed by the oscilloscope through a software program (see steps in Section 3). Do this calibration by using the distance separation between the radioactive source and one of the detectors, measuring the average time difference (step 2.3) of every position. Establish a software communication between the different modules and the computer via a standard bus GPIB (General Purpose Instrumentation Bus) to do this calibration.</li>
</ol>
3. Building the Virtual Instrument Interface
<ol>
	<li>Download and use a LabView software or any similar software. 
	NOTE: To work with Labview, it is necessary to have some knowledge of the &#34;G programming language&#34;. In this language, no code has to be written, and all the actions performed can be done from a software tool palette. An easy guide with practical examples can be found in the help tool.</li>
	<li>Select the array utility from the front panel tool palette (programming variables containers) to save the TDC output data. 
	NOTE: The &#34;front panel&#34; is the graphic interface of the virtual instrument to the user and the &#34;block diagram&#34; is used for software programming.</li>
	<li>Plot the data acquisition (time data from TDC) by selecting a logic instrument from the plots menu. Identify the plots data related with every position of the source. Do this by varying the source distance from the detectors line by some centimeters.</li>
	<li>Take the mean of the data using the statistical functions (mean) from the mathematical menu tool, and choose an interval of values centered in the mean. Then, according to the programming logic followed, use the necessary tools from the array menu to remove all data with values outside this interval.</li>
	<li>Select indicators from the block diagram tool palette to show the number of data stored in each array and identify a few containers with the largest number of data stored.</li>
	<li>Get the mean of the data in each array selected in the step 3.5 and use this information to establish a set of time intervals values for each source position using for this the LabView block diagram tool palette.</li>
	<li>Select an array of indicators from the front panel tool palette to store the mean obtained in step 3.6 for a sequence of measurements.</li>
	<li>Select a case structure from the block diagram tool palette to relate each position with its respective interval from step 3.7, and associate each interval to one virtual LED in an array from the front panel tool palette.</li>
	<li>Notice the time each signal takes to arrive to the TDC channels: when the radioactive source is moved from the middle closer to one detector, observe a movement of the virtual source in the programming array of LEDs (see Figure 5) moving to the right in the computer.</li>
	<li>Include a control (variable programming element) from the front panel tool palette for the total time acquisition. 
	NOTE: The efficiency of the positioning will depend on this control time tool: the more time the acquisition takes, the more precisely the virtual object simulating the radioactive source will give the correct position.</li>
</ol>
4. Graphical Results
<ol>
	<li>For calibration purposes, place the source at any intermediate position relative to one of the coupled pairs of detectors. Take measurements for 30 min, and with the data acquired, take the average of the values accumulated every 2 min. Repeat this process for different source positions and plot the average value from each detector in all positions (see Figures 6 and 7). The differences of the detectors values are plotted in Figure 8.</li>
	<li>To obtain better results, select two detectors having similar data values to form a couple. To test this, put the PMT control voltage to its lower value, in this case 0.5 V. Start measuring the number of detected events with the scaler module for a fixed time by connecting the detector output to the scaler input. Increase the voltage by 0.01 V and measure again. Repeat this process to reach the maximum possible control value, in this case 0.9 V.
	<ol>
		<li>Plot the number of detected events versus the control voltage in semi logarithmic scales (see Figure 9). Couple the pairs of detectors having similar distributions.</li>
	</ol>
	</li>
	<li>To test the sensitivity of the system, place the radioactive source in some equal spacing intermediate positions along the lines, in this case there are five. Acquire data for 5 min in each position, and plot the mean and median of the values obtained for each detector independently (see Figures 10 and 11).</li>
</ol>

<ol><li>Cerello, P., Pennazio, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((An+innovative+detector+concept+for+hybrid+4D-PET%2FMRI%5BTitle%5D)+AND+%22Imaging.+Nucl.+Instr.+Meth.+Phys.+Res%22%5BJournal%5D)">An innovative detector concept for hybrid 4D-PET/MRI.</a> Imaging. Nucl. Instr. Meth. Phys. Res. 702, 1-3 (2013).</li>
<li>Muehllerher, G., Karp, J. S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Positron+tomography+emission%5BTitle%5D)+AND+%22Phys.+Med.+Biol%22%5BJournal%5D)">Positron tomography emission.</a> Phys. Med. Biol. 51, R117-R137 (2006).</li>
<li>Conti, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((State+of+the+art+and+challenges+of+time+of+flight+PET%5BTitle%5D)+AND+%22Physica+Medica%22%5BJournal%5D)">State of the art and challenges of time of flight PET.</a> Physica Medica. 25 (1), 1-11 (2008).</li>
<li>Abreu, Y., Piñera, I., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Simulation+of+a+PET+system+and+study+of+some+geometry+parameters%5BTitle%5D)+AND+%22AIP+conference%22%5BJournal%5D)">Simulation of a PET system and study of some geometry parameters.</a> AIP conference. 1032, 219-221 (2008).</li>
<li>Langner, J. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=%22Development+of+a+parallel+Computing+optimized+head+movement+correction+method+in+PET%22">Development of a parallel Computing optimized head movement correction method in PET</a>. , University of Applied Sciences in Dresden. Saxony, Germany. (2003).</li>
<li>Budinger, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Time-of-flight+PET%5BTitle%5D)+AND+%22J.+Nucl+Med%22%5BJournal%5D)">Time-of-flight PET.</a> J. Nucl Med. 28 (3), 73-78 (1983).</li>
<li>Leo, W. R. <a target="_blank" href="http://scholar.google.com/scholar?hl=en&safe=off&q=author%3aLeo%2C+WR+%22Techniques+for+Nuclear+and+Particle+Physics+Experiments%22">Techniques for Nuclear and Particle Physics Experiments</a>. , second, Springer-Verlag. Germany. (1987).</li>
<li>Budinger, T. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Instrumentation+trends+in+nuclear+medicine%5BTitle%5D)+AND+%22Semin+Nucl+Med%22%5BJournal%5D)">Instrumentation trends in nuclear medicine.</a> Semin Nucl Med. 7 (4), 285-297 (1977).</li>
<li>Burnham, C., Bradshaw, J., Kaufmann, D., Chesler, D., Browner, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((A+Positron+tomography+employing+a+one+dimension+BGO+scintillation+camera%5BTitle%5D)+AND+%22IEEE+Trans.+Nucl.+Sci%22%5BJournal%5D)">A Positron tomography employing a one dimension BGO scintillation camera.</a> IEEE Trans. Nucl. Sci. 30 (1), 661-664 (1983).</li>
<li>Burnham, C., Bradshaw, J., Kaufmann, D., Chesler, D., Steams, C. W., Browner, G. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Design+of+a+cylindrical+shape+scintillation+camera+for+positron+tomographs%5BTitle%5D)+AND+%22IEEE+Trans.+Nucl.+Sci%22%5BJournal%5D)">Design of a cylindrical shape scintillation camera for positron tomographs.</a> IEEE Trans. Nucl. Sci. 32 (1), 889-893 (1985).</li>
</ol>

There are no competing financial interests.

One important aspect of this system is to have a very good control over spatial and time resolutions. The spatial resolution of PET is limited by the physical characteristics of the radioactive decay and the annihilation, but also by technical aspects of the coincidence registration (steps 1.1 and 1.2) and by external sources of errors, such as object movement during the examination5. Thus, the exact position measured will depend on the TOF difference (step 2.4). One technique to achieve a good time resolution...

Positron Emission Tomography is a non-invasive imaging technique used for obtaining digital images of the inner tissues and organs of the body. Various non-invasive techniques exist that allow one to obtain images and information on the internal workings of a patient such as Computer Axial Tomography (TAC) and Magnetic Resonance Imaging (MRI). Both give good spatial resolution and are additionally used for applications in anatomic and physiologic studies. Although comparatively PET gives less spatial resolution, it provides more information concerning the metabolism occurring in the zone of interest. PET is widely used to obtain functional and morphological information; its main clinical applications are in the fields of oncology, neurology and cardiology. Also, PET images can help physicians give better diagnoses, e.g., establish tumor treatment planning.
The basic working principle of PET systems is the detection of two photons or gamma rays coming from a positron-electron annihilation pair, both flying in opposite directions towards the detectors, which commonly consist of scintillator crystals coupled with PMTs. The scintillator crystals transform gamma radiation into visible light, which travels to a PMT which converts the light signal to an electrical pulse via a photoelectric process. Inside the PMT electronic devices called dynodes are present, which increase the magnitude of the electrical charge before sending it to a read-out system. These two detected photons were created when a positron (positively charged electron) emitted by an isotope fluid, which was injected into the bloodstream of the body, annihilates with an electron in the body. The read-out system measures in coincidence the arrival time of the two back-to-back photons with respect to a time reference and further it substrates both times to obtain the difference. The system uses this time difference to calculate the space position where the radiation source emitted both photons, and thus where the electron-positron annihilation occurred.
Some features of PET systems must be defined to optimize the quality of the image and to increase spatial and time resolution. One feature to consider is the Line of Response (LOR), defined as the distance that the two photons travel after the annihilation process. Another feature to consider is the Time of Flight (TOF). The quality of the images also depends on external features, mainly the bodily organs and the patient&#39;s movements during the treatment session1. The isotopes used in PET systems are called Beta+ emitters. These isotopes have a short half-life (on the order of seconds). They are produced in particles accelerators (cyclotrons) when stable elements are bombarded with protons or deuterons causing nuclear reactions. Such reactions transform the stable elements into unstable isotopes, such as C-11, N-13, O-15, F-18 among others2.
There are two types of PET. (1) Conventional: this uses the TOF information only to identify the line along which the annihilation occurred, but it is unable to determine the origin place of the two photons. It requires additional analytical or iterative reconstruction algorithms to estimate this. (2) TOF PET: utilizes the TOF difference to locate the annihilation position of the emitted positron. The time resolution is used in the reconstruction algorithm as a kernel for a localization probability function3.
Our main objective is to demonstrate the primary functions of PET, which is used to locate a radiation source in space. The principal scope of the PET system set proposed here is to provide a basic PET construction guide for the academic public, and to explain, in a simple way, its main properties.

<table><tbody><tr><td>Low threshold Discriminator</td><td>CAEN</td><td>N845</td><td></td></tr><tr><td>Logic Units</td><td>Lecroy</td><td>365AL</td><td></td></tr><tr><td>Time delay</td><td>CAEN</td><td>N108A</td><td></td></tr><tr><td>Oscilloscope</td><td>Tektronic</td><td>TDS3014C</td><td></td></tr><tr><td>Quad Scaler and preset counter</td><td>CAEN</td><td>N1145</td><td></td></tr><tr><td>TDC</td><td>Lecroy</td><td>2228</td><td></td></tr><tr><td>PMT&amp;rsquo;s</td><td>Hamamatsu</td><td>H5783p</td><td></td></tr><tr><td>Power Chasis</td><td>Lecroy</td><td>1403</td><td></td></tr><tr><td>GPIB Interface</td><td>Lecroy</td><td>8901A</td><td></td></tr><tr><td>NIM Power Supply</td><td>Lecroy</td><td>1002B</td><td></td></tr><tr><td>CAMAC Crate</td><td>Borer-co</td><td>1902A</td><td></td></tr><tr><td>Scintillator Crystals</td><td>Bicron</td><td>408</td><td>1 cm x 2 cm x 5 cm</td></tr><tr><td>Power Supply</td><td>Agilent</td><td>E3631</td><td></td></tr><tr><td>Na 22 Radioactive Source</td><td></td><td></td><td>activity 2&amp;nbsp;&amp;mu;Ci</td></tr><tr><td>Software LabView 7.1</td><td>National intruments</td><td></td><td></td></tr><tr><td>lemo cables connectors</td><td></td><td></td><td>2&amp;nbsp;nsec, 3&amp;nbsp;nsec and 8&amp;nbsp;nsec</td></tr><tr><td>isolator film</td><td></td><td></td><td></td></tr></tbody></table>

a basic positron emission tomography system constructed to locate a radioactive source in a bi-dimensional space

A Basic Positron Emission Tomography System Constructed to Locate a Radioactive Source in a Bi-dimensional Space

A simple Positron Emission Tomography (PET) prototype has been constructed to fully characterize its basic working principles. The PET prototype was created by coupling plastic scintillator crystals to photomultipliers or PMT&#39;s which are placed at opposing positions to detect two gamma rays emitted from a radioactive source, of which is placed in the geometric center of the PET set-up. The prototype consists of four detectors placed geometrically in a 20 cm diameter circle, and a radioactive source in the center. By moving the radioactive source centimeters from the center the system one is able to detect the displacement by measuring the time of flight difference between any two PMT&#39;s and, with this information, the system can calculate the virtual position in a graphical interface. In this way, the prototype reproduces the main principles of a PET system. It is capable to determine the real position of the source with intervals of 4 cm in 2 lines of detection taking less than 2 min.

Two main results are achieved with this PET system. First: an efficient synchronization between visual effects of the virtual radioactive source when moving the real radioactive sample. With this program, users have control of the acquisition time, the number of repetitions in the same position, the variation of the interval around the acquisition data mean, among others. Second: the construction of a simple structure of coincidence logic to obtain the time difference between two signals,...

We present a simple but well-constructed Positron Emission Tomography (PET) system and elucidate its basic working principles. The goal of this protocol is to guide the user in constructing and testing a simple PET system.

A simple Positron Emission Tomography (PET) prototype has been constructed to fully characterize its basic working principles. The PET prototype was ...

The overall goal of the following experiment is to show the basic principles of a positron emission tomography system using two pairs of photo detectors. The main advantage of using this prototype over commercial PET systems is that users can see clearly the basic working principles of PET. We first had the idea for this system when we sought to elaborate our lab activity for master students, in the medical physics field.Demonstrating the procedure will be Marcus Fontaine, a technician from my laboratory. Begin work on the PET setup by preparing the detection system. Make each detector using a photo multiplier tube and a polished plastic scintillator piece.Design the scintillator piece to match the size and shape of the photo-multiplier tubelight entrance to allow good coupling. The next step is to wrap the scintillator in black tape. Leave one side uncovered to be coupled with the photo-multiplier tubelight entrance.Put the scintillator aside and begin working with the photo-multiplier tube. Use alcohol and a clean cloth to clean the photomultiplier tubelight entrance. When this is done, get optical grease and apply it to the light entrance until it is covered completely.Return to work with the scintillator and apply optical grease to its uncovered surface. After the optical grease has been applied align the photo-multiplier light entrance and the uncovered scintillator surface. Then couple the two treated surfaces.To complete the detector, wrap the photo-multiplier tube and the scintillator in more black tape as illustrated by this example. Create at least four detectors before moving on to test them. Test the detector by connecting it to a voltage source and to a standard digital oscilloscope.Turn the light off and on in the lab while monitoring the signal on the oscilloscope to verify there are no light losses. Next, connect the photomultiplier tube output to a scaler to count detected events. Adjust the detector voltage to its lowest value;in this case point five volts.Now turn attention to the detector. Place the sodium 22 source directly on the surface of the scintillation portion. Record the number of detected events over three minutes using the scaler.Then increase the control voltage by point zero one volts. Repeat the time to measurement of detected events for this value and all others up to the maximum control voltage. After all detectors have been completely tested, make a plot of the number of detected events versus the control voltage.This plot includes data from 12 detectors. Select two detectors with similar curves to form a coincidence pair. For example, detectors O and I in this plot.After two matched pairs are identified, move on to build and test two coincident systems. Construct the coincident system by placing two matched detectors so the scintillator part of one detector is directly over the scitillator of the other. Next, check the electronic components.The coincidence system requires three nuclear instrumentation modules, a discriminator, a logic unit, and a scaler. Connect the output signals of the detectors to the inputs of the discriminator module. On the logic unit, select the end mode on the front panel.Then connect the two discriminator outputs to the logic unit inputs. Connect the logic unit output to the scaler module to count the events. In this configuration, the scaler should register coincidence events due to cosmic rays hitting the coincidence system.This schematic is of the completed coincidence detection system for testing a pair of detectors. Test each of the pair of detectors before proceeding. The next step is to create the PET setup.Place the four detectors at the corners of a square. Orient the scitillators to point toward the center of the square. The detectors that directly face each other form a coincidence pair.The detector surfaces are about 20 centimeters apart. Continue by connecting each of the detectors to separate channels of a discriminator, a logic block, and a scaler. For coincidence counting with four detectors, implement the logic block depicted in this diagram.Here the detectors are labelled I, J, E, and F and their signals are passed through a discriminator that is not shown. In this diagram, each detector is associated with an OR module. Connect the output of each detector to the inputs of the three OR modules to which it is not associated as indicated by the colored lines.Next connect the OR module's outputs to an AND module to complete the coincidence logic. In the following steps, supply power to only one coincidence pair. Then repeat the steps for the second pair.Return to the detector array with a sodium 22 radiation source. Place the source along the line between the detectors of the coincidence pair. Use one detector as a reference and measure the distance to the source.At the electronics rack, use the discriminator outputs for the two detectors as inputs to an oscilloscope. Display the signals on the oscilloscope with time on the horizontal access. In addition, take the output of the coincidence logic block and input it into the oscilloscope.The resquare signals should appear on the screen. Use time differences between discriminator signals measured on the oscilloscope for later calibration steps. Next, prepare the computer automated measurement and time to digital converter or TDC module.Connect the output of the logic block to the TDC start input. Then connect the outputs of the discriminator to a delay module. Pass the output of the delay module to the TDC's stop inputs.This schematic provides an overview of the setup at this point. Connect the modules and computers with a general purpose instrumentation bus for software control. Install Labview or similar software to create a virtual instrument.At this point, perform TDC calibration steps for the coincidence pair. The next step is to calibrate the system beginning with one coincidence system. Along the line between the two detectors, identify five equally spaced points including the midpoint.This setup has points at four centimeter intervals. Next, place the radiation source between the points. With the source in place, begin to collect coincidence events, TDC data for 30 minutes.Plot the average of all the collected TDC data every one or two minutes. This is a typical plot after the full 30 minutes. The two curves correspond to the two detectors of the coincidence pair.Use a plot of the average of the difference of the TDC values from the two detectors to define a time zone for the purpose of locating the source. Now, move the radiation source to a different marked position between the detectors. Acquire 30 minutes of data and determine a new time zone and repeat for each of the five points.Next, begin to test the sensitivity of the pair. Repeat TDC measurements at all marked points for different collection times. After testing sensitivity move on to set up a virtual instrument.The instrument will associate a software LED with a position of the radiation source. The five vertical LEDs in the center of this array correspond to the five marked positions used to define the time zones. In this figure, our TDC data for two adjacent positions.The mean of the TDC difference data for a position is at the center of an interval. The interval represents the standard deviation of the data. The data should be from the collection time that will be used to resolve the positions two minutes in this protocol.Choose a window of times measurement to associate with a position with an LED by truncating the intervals so that they do not overlap. Setup will be complete after both coincidence pairs are calibrated. At this point, there should be nine marked positions between the detectors.Place the radiation source on one of the positions. Collect data for two minutes and test the accuracy of the virtual instrument in locating the position of the radiation source. These are plots of the response for each detector and a pair that form a coincidence system.The cumulative average TDC value over a one minute interval is given on the vertical axis. The index of the one minute interval is along the horizontal axis. Data was collected over 30 minutes.The different colored lines correspond to different positions of the radiation source. The difference between these average values is plotted here. Linear behavior is expected for each set of measurements allowing conversion between time and distance.Note that there is increased stability as the acquisition time increases. These plots provide a measurement of the sensitivity of coincidence systems. The median and the mean of the TDC counts are plotted along the vertical axis.The index of the position of the radiation source between the detectors E and F is plotted along the horizontal axis. The data used for each point are collected for five minutes. The position index one corresponds to the radiation source being approximately centered.As the index increases, the source moves toward the F-detector. This coincidence system exhibits good spatial resolution since the curve for the median and mean diverge as a function of position. By comparison, the median and mean for this system does not diverge as quickly indicating poor spatial resolution.Once completed, this device can display the location of a radiation source in one minute or less. While attempting this procedure, it is important to remember to put the radiation source in a position where one pair of detectors is sensitive. Don't forget that working with radioactive material can be extremely hazardous.Train in radiation safety to learn the precautions to take while performing this experiment.

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Engineering

Diffuse fluorescence tomography offers a relatively low-cost and potentially high-throughout approach to preclinical in vivo tumor imaging. The methodology of optical data collection, calibration, and image reconstruction is presented for a computed tomography-guided non-contact time-domain system using fluorescent targeting of the tumor biomarker epidermal growth factor receptor in a mouse glioma model.

Computed Tomography-guided Time-domain Diffuse Fluorescence Tomography in Small Animals for Localization of Cancer Biomarkers

Source: Jamadar, S. et. al. Radiotracer Administration for High Temporal Resolution Positron Emission Tomography of the Human Brain: Application to FDG-fPET. J. Vis. Exp. (2019)This video demonstrates the quantification of brain glucose metabolism using positron emission tomography (PET). The participant is infused with the tracer F-18 fluorodeoxyglucose (FDG) during scanning. FDG accumulates in active neurons and emits positrons upon F-18 decay. These positrons interact with electrons,...

Positron Emission Tomography Imaging of the Human Brain Using a Radiotracer

In the past, small animal irradiation was usually performed without the ability to target a well-delineated tumor volume. The goal was to mimic the treatment of human glioblastoma in rats. Using a small animal irradiation platform, we performed MRI-guided 3D conformal irradiation with PET-based sub-volume boosting in a preclinical setting.

PET and MRI Guided Irradiation of a Glioblastoma Rat Model Using a Micro-irradiator

Here a protocol for continuous blood sampling during PET/CT imaging of rats to measure the arterial input function (AIF) is described. The catheterization, the calibration and setup of the system and the data analysis of the blood radioactivity are demonstrated. The generated data provide input parameters for subsequent bio-kinetic modeling.

Continuous Blood Sampling in Small Animal Positron Emission Tomography/Computed Tomography Enables the Measurement of the Arterial Input Function

This method estimates the absorbed dose of different structures for peptide-receptor-radionuclide-therapy (PRRT) with the possibility of avoiding organ overlap on 2D-projections. Serial whole-body planar images permit estimation of mean absorbed doses along the whole body, while the hybrid approach, combining planar images and 3D-SPECT/CT image, overcomes the limitations of structure overlapping.

A Whole Body Dosimetry Protocol for Peptide-Receptor Radionuclide Therapy (PRRT): 2D Planar Image and Hybrid 2D+3D SPECT/CT Image Methods

This manuscript describes a protocol for neutron radiography and computed tomography of biological samples using a High Flux Isotope Reactor (HFIR) CG-1D beamline to measure a metal implant in a rat femur, a mouse lung, and an herbaceous plant root/soil system.

Neutron Radiography and Computed Tomography of Biological Systems at the Oak Ridge National Laboratory's High Flux Isotope Reactor

Here we present a protocol to perform preclinical positron emission tomography-based radiotherapy in a rat glioblastoma model using algorithms developed in-house to optimize the accuracy and efficiency.

Positron Emission Tomography-based Dose Painting Radiation Therapy in a Glioblastoma Rat Model using the Small Animal Radiation Research Platform

Quantitative measurements of oxygen and glucose metabolism by PET are established technologies, but details of practical protocols are sparsely described in the literature. This paper presents a practical protocol successfully implemented on a state-of-the-art positron emission tomography-computed tomography scanner.

Multi-Tracer Studies of Brain Oxygen and Glucose Metabolism Using a Time-of-Flight Positron Emission Tomography-Computed Tomography Scanner

This paper describes the radiosynthesis, formulation, quality control of a new radiolabeled probe (i.e., 68Ga-labeled nanobody NM-02), and its use for small animal PET/CT imaging in a xenograft model.

Radiosynthesis, Quality Control, and Small Animal Positron Emission Tomography Imaging of 68Ga-Labelled Nano Molecules

Progress has been made in utilizing spin echo resolved grazing incidence scattering (SERGIS) as a neutron scattering technique to probe the length-scales in irregular samples. Crystallites of [6,6]-phenyl-C61-butyric acid methyl ester have been probed using the SERGIS technique and the results confirmed by optical and atomic force microscopy.

Using Neutron Spin Echo Resolved Grazing Incidence Scattering to Investigate Organic Solar Cell Materials

Learn to construct a basic PET system using photo multiplier tubes and plastic scintillators for medical physics education. This hands-on method helps students understand positron emission tomography principles through practical experience.

A Basic Positron Emission Tomography System Constructed to Locate a Radioactive Source in a Bi-dimensional Space

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