Radiography

Remains strong, there is nodoubt that advanced imaging capabilities such as dual-energyradiography and digital tomosynthesis volume imaging have resultedin a focus on and greater emphasis of flat-panel DR technologiesfor targeted procedures that can reduce the need for computedtomography, MRI and ultrasound examinations.The American College of Radiology has recently publishedpractice guidelines for digital radiography8,9including a review of digital radiography technologies, clinicalconsiderations for implementation and quality controlrecommendations. This information is an excellent resource for allindividuals responsible for digital radiography in the clinicalenvironment.ConclusionDigital radiography detectors (CR and DR detector systems) arenow in the majority. Cassette-based photostimulable storagephosphor detectors comprise the largest segment of digitaldetectors; however, cassetteless, integrated detectors areincreasing in areas that demand high efficiency and highthroughput. The historical comparison of "CR vs. DR" while still aconsideration for making an informed decision for choice ofadigital radiography system, is of less importance, as the advanceof technology has blurred the differences. Image acquisition speedof AMFPIs is enabling advanced acquisition and processingcapabilities such as dual-energy radiography and digitaltomosynthesis, which will likely become common methods that areused to overcome the superimposition limitations of conventionalprojection radiography and result in more accurat ediagnoses. Justexpect to pay more for advanced technology capabilities, and besure to justify the expense in terms of realistic workloads andthroughput requirements; otherwise do not expect a decent return oninvestment. Knowledge of DR system characteristics, advantages,disadvantages and operational details provide the insight andconfidence to make a reasonable, informed decision on equipmentselection and optimization of digital radiography implementationfor a specific purpose.REFERENCESSeibert JA, Bogucki TM, Ciona T, et.al. Acceptance testing and quality control of photostimulable storage phosphor imaging systems: Report of AAPM Task Group 10. AAPM Report #93. American Association of Physicists in Medicine, College Park, MD. (2006) Available at RPT_93.pdf. Accessed April 27, 2009.Leblans PJ, Struye L, Willems P. New needle-crystalline CR detector. Proc SPIE. 2001;4320:59-67.Baysal MA, Toker E. CMOS Cassette for digital upgrade of film based mammography systems. Proc SPIE. 2006;6142:61421Q.Pisano ED, Yaffe MJ. Digital mammography. Radiology. 2005;234:353-362.Seibert JA. Digital radiographic image presentation: Pre-processing methods. In: Samei E, Flynn MJ, eds. 2003 Syllabus: categorical course in diagnostic radiology physics - Advances in digital radiography. Oak Brook, IL: Radiological Society of North America (RSNA);2003:147-151.Rowlands JA, Yorkston J. Flat panel detectors for digital radiography. In Medical Imaging, Volume 1, Physics and Psychophysics, Beutel J, Kundel HL, Van Metter RL eds. Societyof Photooptical and Instrumentation Engineers (SPIE). Bellingham, WA. 223-328, 2000.Samei E, Saunders RS, Lo JY, et al. Fundamental imaging characteristics of a slot-scan digital chest radiographic system. Med Phys. 2004;31:2687-2698.Williams MB, Krupinski EA, Strauss KJ, et al. Digital radiography image quality: image acquisition. JACR. 2007;4:371-388.Krupinski EA, Williams MB, Andriole K, et al. Digital radiography image quality: Image processing and display. JACR. 2007;4:389-400.

Chest RadiographyLECTURE.2PLEASE TURN ALL CELL PHONES TO SILENT MODELearning Objectives By the end of this Lecture the student will be able to: • List and identify the major anatomical structures of the chest • List the common indications for chest radiography • Identify the common technical factors for chest radiography • List the basic and Optional projections for chest radiography • Discus the correct body position, part position, central ray, and • center point for specific positions for each projection. • Critique and evaluate chest radiographs based on position, • collimation and central ray, exposure, and structure best shown.References • Text book of radiographic positioning and related anatomy; by • Kenneth L.Bontrager • Positioning in Radiography: By k.C.Clarke. • Websites • Anatomy • Thoracic cavity (chest) • Surrounded by boney thorax • Separated from abdomen by diaphragm • Muscular partition • Dome shaped • Lungs drape over diaphragmAnterior Posterior Boney Thorax • ENCLOSE THE ORGANS • STERNUM (breast bone) • 12 PAIR OF RIBS • 12 THORACIC VERTEBRA • ATTACH UPPER EXTREMITY • 2 CLAVICLES • 2 SCAPULAA A H H  B   B  C  C Respiratory System 1. Lungs • Lobes • Right 3 lobes • Left 2 lobes • Terminology • Apex • Hilum • Base • Costophrenic anglesBronchial Tree 2. Bronchi • Air tubes leading into the lung • Right more vertical than left • Branching structure • Primary è 2ndary è • Only primary visible on PA projection PMiscellaneous • Mediastinum contents • Trachea • Major vessels • Esophagus • Lymphatic's • Heart • ThymusTechnical Aspects • For chest radiography, a lead-rubber Gonad shield should be employed so to protect the abdomen below the chest (using vinyl-covered lead apron) around the waist for all patients of reproductive age, children, and pregnant women. • Low contrast ( long-scale contrast) contrast must be adopted using ‘High kV Technique ’ (100 - 130 kVp) with low mAs (3 mAs) at 72 inches (180 cm) FFD (SID). • Higher mA and short exposure times (0.01 s) must be used to reduce movement blur (due to movement

Digital radiography refers to all non-film-based methodologies to capture radiological information. Digital imaging has been used in the practice of dentistry since the 1980s to diagnose diseases of the paranasal sinus and TMJ disorders. However, dentists in North America have been slow to adopt digital radiography. Estimates by manufacturers place the number of dentists who have purchased these systems to be approximately 7,000. In a survey conducted in 1998, 67% of the dentists responding to the question of their next major purchase wish, if “money was no object,” said that they would buy a digital radiography system.1Digital imaging offers several advantages. Information obtained in digital form can be processed, stored, and transmitted from one place to another using communication networks. The lower dose of radiation and time saved in acquisition and viewing of an image is an improvement over conventional radiography. Images produced by digital systems can also be manipulated using computer software applications to increase diagnostic utility and electronically transmitted for referrals. In addition, digital imaging does not require chemical processing. Other advantages include image analysis and image reconstruction. There is also evidence that utilization of digital radiography is not only more economical to establish than a conventional radiographic system, but also less expensive to maintain.2The purpose of this article is to review technologies basic to digital imaging that enable acquisition and viewing of an image, and to recognize limitations of the technology. ELEMENTS OF DIGITAL IMAGING CYCLEThere are five basic elements of an imaging cycle: acquisition of a digital image; processing the acquired image using image analysis, and image manipulations using software applications; storage for easy access and retrieval; communication or image transmission between peers; and presentation or viewing of the image using monitors or workstations. This article examines each these elements and also identifies concerns that are essential to the clinical practice of dentistry.Figure 1. Elements of imaging.The steps involved in a digital imaging cycle are illustrated in Figure 1. There are three basic components of a digital imaging system: computers (desktops, viewing stations), detectors (image acquisition devices) (Figures 2a and 2b), and scanners (Figures 3a and 3b). The computer controls acquisition, storage, processing, retrieval, and display of a digital image. Detectors are primarily used to capture or acquire images from the source and store them until they are processed. A detector converts the x-ray beam into an electronic signal. Scanners are used to process the image