Xrays are a form of light with a wavelength in the range of 0. In this article, we will outline the basic science behind ct scans, describe the principles of interpretation, and highlight their advantages and. A basic knowledge of xray physics is complementary to knowledge of xray interpretation. The quiz below is designed to help you revise what you know about ct physics and instrumentation. Mri an abbreviation of magnetic resonance imaging is an imaging modality that uses nonionizing radiation to create useful diagnostic images in simple terms, an mri scanner consists of a large, powerful magnet in which the patient lies. The presentation style, using cases and multiple choice questions, to outline key concepts in practical ct imaging, is spot on with how the abr is beginning to test residents in physics. Since the first ct scanner was developed in 1972 by sir godfrey hounsfield, the modality has become established as an essential radiological technique applicable in a wide range of clinical situations. Ct scans interpretation principles basics teachmeanatomy.
Computed tomography ct is a method of acquiring and recon structing the image of a thin cross section on the basis of measure ments of attenuation. History 1924 mathematical theory of tomographic image. Whiting introduction slightly more than three decades old, computed tomography ct continues to advance rapidly in both imaging performance and widening clinical applications. These beautiful notes are for those sitting the first frcr physics exam and are based on, and cover, the entire scope of the rcr radiology integrated training initiative riti elearning upon which the first frcr physics exams are based. Fundamentaldifferencesbetween data from differentmodalities will also be discussed. Mcnittgray, phd this article describes basic radiation dose concepts as well as those speci. Dose measurement in ct measures of dose, effects of patient size, and dose reduction techniques. Anderson cancer center outlines challenges in petct for rt dose efficiency of single slice ct and multislice ct radiation dose in petct spatial and temporal resolution free breathing vs breath. This paper forgoes the usual physics equations to describe how cts saturate in a simple and intuitive way. Spacetime diagrams, spacetime, geometry introducing spacetime classically we have an absolute time, which can be viewed as a onedimensional euclidean space, r, plus an absolute threedimensional space, r3. They have been separated into chapters covering basic science, xray imaging, ct imaging, ultrasound imaging, mr imaging, molecular imaging, and radiation dosimetry, protection and legislation. Physics sample questions royal college of radiologists.
In this article, we will outline the basic science behind ct scans, describe the principles of interpretation, and highlight their advantages and drawbacks compared to other imaging techniques. Basic principles of computed tomography physics and technical. The major topics those are studied in physics are mechanics, electricity, magnetism, heat, sound, light and other radiation, and the structure of atoms. In helical ct, pitch is defined as table movement in 360 degrees beam width patient dose in 360 degrees beam width. Volume and surface rendering are two different methods for reformatting axial images into threedimensional views. A radio wave antenna is used to send signals to the body and then a radiofrequency receiver detects the emitted signals. Cardiac ct prospective and retrospective gating, temporal resolution, and radiation dose. The notes also provide an excellent overview for anyone interested in learning about the physics of radiology. Crosssections are reconstructed from measurements of attenuation coefficients of xray beams in the volume of the object studied. In helical ct, the scanner never images a single slice. Additionally, the case explanations are easy to understand no matter your understanding of basic physics.
Duong 2 1 sprawls educational foundation and emory universitydepartment of radiology and imaging sciences, montreat, usa. With advancements in technology, it is rapidly replacing many diagnostic radiographic procedures. You need to be able to talk to experts communicate your needs to physicistsradiographerstechs build an mr vocabulary terminologyjargon gain some intuition behind imaging concepts. The basic concepts of ct physics made easy lj notes available in paperback. This extremely small wavelength indicates that the xrays have a much higher energy than visible light. Petct simulation for radiation therapy applications tinsu pan, ph. Abstract current transformer ct saturation, while a fairly common occurrence in protection systems, is not often clearly understood by protective relay engineers. This article describes basic radiation dose concepts as well as those specifically developed to describe the radiation dose from computed tomography ct. Outlines petct simulation for radiation therapy applications. Interactive study guides, l oads of other practice content in anatomy, physics, patient care and procedures to prepare you for the ct registry exam.
Ideally, these magnets are randomly arranged in polarity throughout the core, as shown in fig. Basic principles of computed tomography physics and technical considerations kyongtae t. A computerized tomography is an xray imaging procedure in which a narrow beam of xrays is aimed at a patient and quickly rotated around the body. Pdf the article explores the fundamentals of emission computed tomography ct from a nonmathematical approach. About the tutorial physics is one of the disciplines of natural science that studies about the various aspects of the matters and energy. The ct accreditation program involves submission of clinical and phantom images, dose measurements and scanning protocols. The basic concepts of ct physics made easy lj notes by lawrence mcnair. Gullapalli, phd artifacts in magnetic resonance mr imaging result from the complex. Ct scanner uses a motorized xray source that rotates around the circular opening of a donutshaped structure called a gantry.
Computed tomography xrays irradiated on body, some rays are absorbed and some pass through the body to produce an image. The aapmrsna physics tutorial for residents search for isotropic resolution in ct from conventional through multiplerow detector1 mahadevappa mahesh, phd computed tomography ct is a method of acquiring and reconstructing the image of a thin cross section on the basis of measurements of attenuation. Compared to ct and mr images, pet images appear much blurrier and or noisier, due to the relatively limited number of photons that can be collected during an imaging study. Several ctspecific dose descriptors have been developed. They are not a replacement for studying the riti modules, but hopefully make things a little more structured and easy to. May 21, 2012 a basic description of the mechanism of ct computed tomography scans for medical use in remote sensing.
The assessment of the uncertainty budget becomes a challenge for all researchers. Factors that affect radiation dose from ct include the beam energy, tube currenttime product, pitch, collimation, patient. Computed tomography ct scanning is an extremely common imaging modality in modern medicine. Overview of online ct program arrt ct content specifications. Physics of imaging systems basic principles of magnetic resonance imaging ii. Filtered back projection 2 filtered back projection 3 filtered back.
A basic description of the mechanism of ct computed tomography scans for medical use in remote sensing. This physics textbook is designed to support my personal teaching activities at duke university, in particular teaching its physics 141142, 151152, or 161162 series introductory physics for life science majors, engineers, or potential physics majors, respectively. Specifics of the qc program for ct are provided by the acr in this manual. Physics of imaging systems basic principles of magnetic. In plain xray imaging, the film directly absorbs penetrated x rays. Jan 11, 2016 computed tomography xrays irradiated on body, some rays are absorbed and some pass through the body to produce an image. Physics of imaging systems basic principles of magnetic resonance imaging ii prof.
In cat scanning, an electronic device called a detector array absorbs the penetrated xrays, measures the xray amount, and transmits the data to a. Singlephoton emission computed tomography spect is a sensitive and specific 3d technique to monitor in vivo functional processes in both clinical and preclinical studies. Xray ct scanners can easily resolve points less than 1 mm in size, while pet scanners cannot reliably. Introduction to ct physics image generation what is computed tomography ct.752 1292 482 281 530 1304 48 451 444 1095 894 1406 581 522 502 353 570 1028 398 1231 118 1604 1429 295 114 223 624 1097 151 189 1330 1217 825 44 905 1199 874 441 279 355