Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Ultrasound WHO. “Scanning System, Ultrasonic.” From the publication: Core Medical Equipment. Geneva, Switzerland, 2011 History Beginnings in the 1880s when Pierre Curie introduced simple echo sounding methods. 1913 discovery of SONAR -(Sound Navigating and Ranging) First introduced to medical world in 1950s Applications Dog whistle Bets and dolphins communication and orientation Sonar Submarine-boat communication Applications Ultrasound-welding (for plastic) Materials testing Multiphase flow measurement Medical Applications Disinfection of instruments Imaging Detection of tumors (Oncology) Assesment of the development of fetus (OB/GYN) Evaluation of blood flow (Cardiology) Insertions Therapy WHO. “Scanning System, Ultrasonic.” From the publication: Core Medical Equipment. Geneva, Switzerland, 2011 Principals of Operation • • • The ultrasound examination is usually carried out with the patient in the supine position. it is often useful to turn the patient in an oblique position or to scan from the back in a prone position, e.g. when scanning the kidneys. Ultrasound also allows examination of the patient in a sitting or standing position, which may help in certain situations to diagnose stones or fluid collection (e.g. pleural effusion) WHO. “Manual of Diagnostic Ultrasound, Second Edition.” WHO, 2011 Frequency Range Ultrasound_range_diagram.png:LightYear at en.wikipedia Ultrasound_range_diagram_png_(sk).svg:LightYear at en.wikipedia derivative work: Coolth [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], from Wikimedia Commons Frequency Adjustment Adjustment • The choice of frequency (and transducer) depends on the penetration depth needed. For examination of the abdomen, it may be useful to start with a lower frequency (curved array, 3.5 MHz) and to use a higher frequency if the region of interest is close to the transducer, e.g. the bowel . • Adaptation to the penetration depth needed: the whole screen should be used for the region of interest. • The mechanical index should be as low as possible (< 0.7 in adults). • The time gain compensation (TGC) setting must compensate for attenuation, e.g. depending on the abdominal wall, to obtain a homogeneous image. It is useful to find a good TGC setting when scanning a homogeneous section of the tissue, e.g. the right liver lobe in the abdomen, before moving the transducer to the region of interest (Fig. 2.3, Fig. 2.4, Fig. 2.5). • The focus, or zone of best resolution, should always be adjusted to the point of interest. WHO. “Manual of Diagnostic Ultrasound, Second Edition.” WHO, 2011. Physics MEDIA 1 - water MEDIA 2 - air TRANSMITTED WAVE Nilock (2010), Ray optics diagram [image]. Retrieved from https://en.wikipedia.org/wiki/Ray_(optics)#/media/File:Ray_optics_diagram_incidence_reflection_and_refraction.svg Indices of Refraction Josell7 (2010), Indices of Reflection [image]. Retrieved from https://commons.wikimedia.org/wiki/File:RefractionReflextion.svg Principle Georg Wiora (Dr. Schorsch) (Self drawn with Inkscape) [GFDL (http://www.gnu.org/copyleft/fdl.html), CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/) or CC BY-SA 2.5 (http://creativecommons.org/licenses/by-sa/2.5)], via Wikimedia Commons Principle Bruce Blaus. “Fetal Ultrasound.” Wikipedia Commons, November 9, 2015. Retrieved from: https://commons.wikimedia.org/wiki/File:Fetal_Ultrasound.png Principals of Operation Use: Generally, modern ultrasound equipment consists of ‘all-round scanners’. Two transducers, usually a curved array for the range 3–5 MHz and a linear array for the range greater than 5 MHz to 10 MHz, as a ‘small-part scanner’ can be used as ‘generalpurpose scanners’ for examination of all body regions with the B-scan technique WHO. “Manual of Diagnostic Ultrasound, Second Edition.” WHO, 2011. Doppler fetal monitor: Principle Dirk Hünniger (2007), Doppler Sonography Blood Flow Diagram [image]. Retrieved from https://en.wikipedia.org/wiki/Doppler_fetal_monitor#/media/File:DopplerSonographyBloodFlowDiagram-de.svg Transducer Linear array: small parts, superficial vascular, obstetrics Curved array: abdominal, obstetric, transabdominal, or for transvaginal or transrectal or pediatric imaging Phased array: heart, liver, spleen, fontanelle, temple Transducer Wikipedia. “ Medical Ultrasound.” Wikipedia, pgs 1-15. Retrieved from: https://en.wikipedia.org/wiki/Medical_ultrasound Distance equal to less than a wavelength for the minimum interference and reduced grating lobes Transducer Rakruger (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commo Transducer Rakruger (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons Transducer From pulse generator Delay Dirk Hünniger (Own work) [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons Transducer Transducer WHO. “Manual of Diagnostic Ultrasound, Second Edition.” WHO, 2011 . Images A-Mode WHO. “Manual of Diagnostic Ultrasound, Second Edition.” WHO, 2011 . Images B-Mode WHO. “Manual of Diagnostic Ultrasound, Second Edition.” WHO, 2011 Images M-Mode (Motion-mode imaging) Image line is a function of time WHO. “Manual of Diagnostic Ultrasound, Second Edition.” WHO, 2011 Examples: • Heart valves • Cross-section of a carotid artery . Images Doppler Mode WHO. “Manual of Diagnostic Ultrasound, Second Edition.” WHO, 2011 . Images Doppler Mode - Flow track (reverse flow) WHO. “Manual of Diagnostic Ultrasound, Second Edition.” WHO, 2011 . Images 3D Imaging (4D + time) 4dsonogram.jpg: Madcapslaugh Ecografía_4D_-_Feto_12semanas_D.jpg: Rizome derivative work: Rizome (4dsonogram.jpg Ecografía_4D__Feto_12semanas_D.jpg) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons Images Frame Rate (for f = 3.5 MHz) Bruce Blaus. “Fetal Ultrasound.” Wikipedia Commons, November 9, 2015. Retrieved from: https://commons.wikimedia.org/wiki/File:Fetal_Ultrasound.png 4dsonogram.jpg: Madcapslaugh Ecografía_4D_-_Feto_12semanas_D.jpg: Rizome derivative work: Rizome (4dsonogram.jpg Ecografía_4D__Feto_12semanas_D.jpg) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons Resolution The size of an area in a scene that is represented by one pixel in the image Lower resolution leads to data reduction! No author provided. Thegreenj~commonswiki assumed (based on copyright claims). [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0/)], via Wikimedia Commons Resolution Tradeoff between resolution and attenuation ↑higher frequency ↓shorter wavelength Power loss: ↑ higher attenuation dB 1 cm MHz Typical Ultrasound Frequencies: Deep Body 1.5 to 3.0 MHz Superficial Structures 5.0 to 10.0 MHz Gel WHO. “Manual of Diagnostic Ultrasound, Second Edition.” WHO, 2011 A coupling agent is necessary to ensure good contact between the transducer and the skin and to avoid artefacts caused by the presence of air between them Safety Ultrasound at high energy can be used to ablate (kill) tissue. Cavitation (bubble formation) Temperature increase is limited to 1º C for safety Block Diagram RF AMPLIFIER FM DEMODULATOR AMPLIFIER SIGNAL PROCESSING SPEAKER DISPLAY RECEPTOR BODY TRANSMITTER OSCILLATOR Engineering World Health (2015), Ultrasound. Retrieved from library.ewh.org Common Problems Broken Probe Broken cables Power supply User error Therapy George Lewis Jr (2008), ATDD Therapy [image]. Retrieved from https://en.wikipedia.org/wiki/Therapeutic_ultrasound#/media/File:ATDD_Topical_Application.jpg Phacoemulsification Takuma-sa (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons Kidney Stones A biplane x-ray apparatus is used to make sure the stone is at the focal point of spark-generated shock waves from the ellipsoidal reflector. Blausen.com staff. "Blausen gallery 2014". Wikiversity Journal of Medicine. DOI:10.15347/wjm/2014.010. ISSN 20018762. (Own work) [CC BY 3.0 (http://creativecommons.org/licenses/by/3.0)], via Wikimedia Commons Kidney Stones Lithotriptor Machine By DiverDave (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons Kidney Stones Ureteroscopy Percutaneous Nephrolithotomy No author (2005), Ultrasonic instrument and kidney stone [Image]. Retrieved from https://commons.wikimedia.org/wiki/File:Kidney_Stone_Image_4172-PH.jpg