Medical Imaging System Unit-III: Medical Imaging System: Lectures required Topic Books L17-L18 L19-L20 L21-L22 Medical Imaging System Instrumentation for diagnostics X-rays, basic properties of X-rays, X-ray machines, Special imaging techniques. Ultrasonic imaging systems physics of ultrasound, biological effect of ultrasound, Ultrasonic A Scan, B Scan, M Scan, real-time ultrasonic imaging system T2, T1 VM Umale Dept. of Electronics and Telecommunication Engineering

Dept. of Electronics and Telecommunication Engineering classification: Classification of basic modes of transmission Ultrasound waves can be transmitted in various forms Pulsed ultrasound Continuous doppler Pulsed doppler Range gated pulsed doppler Classification of Ultrasonic imaging system The images of the internal structure of the body can be obtained with following scanning techniques or scan modes A -scan display M-scan display B-scan display Real time mode vm umale Dept. of Electronics and Telecommunication Engineering

Dept. of Electronics and Telecommunication Engineering classification: Pulsed ultrasound – Continuous doppler- Pulsed doppler- Range gated pulsed doppler- vm umale Dept. of Electronics and Telecommunication Engineering

Pulsed –echo ultrasound setup Block diagram Pulse repetition freq. Generator Transmitter Transducer Time delay Saw tooth Generator Swept Gain Wide Band Amplifier Time Marker Detector Video Amplifier CRO Gain Control vm umale Dept. of Electronics and Telecommunication Engineering

Unit-III: Medical Imaging System: Ultrasonic probes VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Imaging can provide valuable information such as size, location , displacement/velocity of a given internal organs or structures. No need of surgery No potentially harmful radiation Non-invasive imaging Non-traumatic imaging Tumors, cysts, etc having different densities than body organ tissues therefore easy to detect by ultrasonic imaging techniques The images of the internal structure of the body can be obtained with various ultrasonic imaging( Scanning) techniques or Scan modes vm umale Dept. of Electronics and Telecommunication Engineering

Dept. of Electronics and Telecommunication Engineering classification: Ultrasonic imaging system The images of the internal structure of the body can be obtained with following Scanning techniques or Scan modes: A -scan display M-scan display B-scan display Real time mode vm umale Dept. of Electronics and Telecommunication Engineering

1D, 1dimensional information Ultrasonic imaging system A Scan: 1D, 1dimensional information Echoes are displayed as vertical blips as the beam is swept across the CRT The height of the vertical blips is the strength of the echo The position from L to R across CRT face gives the depth of the tissue from the transducer. VM Umale Dept. of Electronics and Telecommunication Engineering

For A Scan Application (requirement) CRT- Ultrasonic imaging system For A Scan Application (requirement) CRT- Electrostatic defection type with post defection acceleration of electron beam. It helps to get bright trace with low defecting voltage Flat face CRT integrated with storage facility Application of A-scan mode 1. Echoencephaloscope / Echoencephalography 2. Echophthalmoscope VM Umale Dept. of Electronics and Telecommunication Engineering

Application of A-scan mode 1. Echoencephaloscope / Echoencephalography Ultrasonic imaging system Application of A-scan mode 1. Echoencephaloscope / Echoencephalography The Midline surface of the brain Head injury -Tilting of brain due to bleeding ,shift in position of vertical blips -Tumors grows in the brain, anatomy of brain is altered The instrument for diagnosis & detection of the mid line of the brain is called “Echoencephaloscope” - Measuring range – 0-18 cm of tissue depth - Frequency range – 1-3MHz - Probe diameter – 15-20mm ( for 2Mhz) For elderly patient select f= 1MHz, Echoes received frame the brain. VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Scan-A mode: e.g. Echoencephalogram Echoes received from the brain In the normal brain, the mid line echoes coincide for each way In the abnormal case, there is a shift between the two echoes VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Scan-A VM Umale Dept. of Electronics and Telecommunication Engineering

Application of A-scan mode 2. Echo-ophthalmoscope Ultrasonic imaging system Application of A-scan mode 2. Echo-ophthalmoscope A Scan * Usefule in ophthalmoscopy for the dignosis Retinal dislocation, Intra ocular tumours, Vitreous opacities orbital tumour, Lens dislocation. If helps in the measurement of axial length in patient with progressive myopia, localization of intra ocular foreign bodies extraction of non magnetic foreign bodies. VM Umale Dept. of Electronics and Telecommunication Engineering

Application of A-scan mode 2. Echo-ophthalmoscope Ultrasonic imaging system Application of A-scan mode 2. Echo-ophthalmoscope - It employs 7.5 15MHz pencil type transducer Echoes obtained when performing an anterior- posterior examination along the optical axis ( ref surface of the lid, surface of the cornea. the anterior lens capsules, the posterior lens capsule, The posterior wall of the globe (retina echo at, choroid & sclera), refrobulbar fat.) Thickness of lens 3 mm Gross axial length-24mm & depth of anterior chamber = 3mm VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Scan-A mode: e.g. Echopohthalmoscope Acoustics landmarks in the normal eye along the optical axis. The electronic markers shown on the figure represents 2mm of actual tissue depth VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Typical M-mode display from various structures of the heart with different directions of the probe VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Block diagram of an echocardiograph circuit VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Difference between Scan-A, B and M Principle of time-motion (M-Mode) display VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Difference between A-scan and B-scan displays VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Scan-B VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Types of Scanning arrangement: Three Types of Scanning arrangement Linear scan Sector scan Compound scan VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Real time Image System Different arrangements in multi-element array scanners Linear sequential array Curve –linear array Linear phased array Phased array VM Umale Dept. of Electronics and Telecommunication Engineering

Ultrasonic imaging system Real time Image System VM Umale Dept. of Electronics and Telecommunication Engineering

A : Thanks a lot VM Umale Dept. of Electronics and Telecommunication Engineering

xxxxx Echophthalmoscope Ultrasonic imaging system : VM Umale Dept. of Electronics and Telecommunication Engineering