L17 - Biological effects and Safety.pdf

FRD40721 - Radiography & Medical Imaging Science ( Ultrasound Imaging ) Lecture 17 Biological Effects and Safety in Ultrasound Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Advantages of Ultrasound • Easily accessible • Portable •...

FRD40721 - Radiography & Medical Imaging Science ( Ultrasound Imaging ) Lecture 17 Biological Effects and Safety in Ultrasound Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Advantages of Ultrasound • Easily accessible • Portable • Comparatively inexpensive • Non-ionizing radiation • Offers dynamic imaging/real time • Generally non-invasive Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Disadvantages of Ultrasound • Operator dependent • Unable to penetrate bone • Disrupted by gas/air – limited visualisation of gas-filled bowel or structures underlying bowel • Visualisation limited by patient factors, eg. body habitus Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae The Scanning Environment: Safety of the Patient & Radiographer It is important to prepare: • Machine, transducers, gel • Chair, examination couch • Organised, neat and tidy room, remove obstacles • Clean linen • Adjustable lighting • Patient privacy Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae US Machine • Ergonomic design • B-mode, colour Doppler, spectral Doppler, 3D/4D capabilities • Range of transducers • Optimum image quality • Monitor • Compatible with PACS and printing facilities Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Transducers • Light weight • Supports for cables • Cables long enough for unrestricted use • Easy to change • Grip – Non slip – Comfortable Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Examination Couch • • • • • • • Height adjustable Foot pedal control Side rails Lockable wheels Tilt for vascular work Adjustable head rest Narrow sides to reduce reach Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Examination Chair • • • • • Back rest chair Wheels Foot rest Height and tilt adjustable User friendly adjustment Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Professional Behaviour • Communicate with patient • Informed consent prior to commencing scan • Respect patient privacy • Consider patient comfort • Respect patient dignity • Provide care in a non discriminatory manner • Documentation Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Safety Issues • Room – Set up, emergency procedures • Equipment – Electrical safety, routine machine maintenance, cross infection prevention • Patient – Compliance, infection, injury prevention • Ultrasound – Bioeffects Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Patient Safety • Patient identification • Patient compliance – Hearing or vision impaired – Language other than English – Abusive, aggressive, drug or alcohol affected – Ability to follow instructions, attain required positions • Patient safety – Examination couch – Responsibility of the sonographer; (Brakes, Height, Side rail) • Infectious patients Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Bioeffects of Ultrasound • Ultrasound is a mechanical form of energy which interacts with the tissue that it passes through. • Although there are no known risks associated with the current clinical applications of diagnostic ultrasound, bioeffects of ultrasound have been demonstrated in laboratory conditions. Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Biological effects – Occur due to energy deposited in the tissue. – The interaction of energy in tissues categorised into: • Thermal effects (heating). • Mechanical effects (such as cavitation). Course: FRD3062 Medical Imaging Science and Methods 4 (Advanced Ultrasound): Lecture 5 fchs.ac.ae Thermal effects Ultrasound energy Absorption Heat • Temperature elevations become greater from: B-mode  colour Doppler  Spectral Doppler • Adult tissues are more tolerant of temperature changes than fetal and neonatal tissues Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Thermal effects (heating): Depends on: • Increase power output (not gain). • Increase frequency. • Increase exposure time. • Decrease field of view (FoV). • Low perfusion (blood supply). • Increase tissue absorption coefficient. Course: FRD3062 Medical Imaging Science and Methods 4 (Advanced Ultrasound): Lecture 5 fchs.ac.ae Mechanical effects Cavitation: • Formation of gas bubbles within the tissue due to pressure changes within the tissue. • Collapse of the bubble formed may cause serious damage. • Depends on: tissue characteristics, exposure time, pulse duration and PRF. Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae ALARA Principle •A •L •A •R •A s ow An ultrasound must be medically indicated and not used for entertainment purposes Adequate training of sonographers easonably Care must be taken to minimise : (1) acoustic output (2) exposure times chievable Efficient scanning s Be aware of safety indices Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Cross infection Prevention • All blood, body fluids (other than sweat), mucous membranes and non in-tact skin are potential sources of infection. • Protection of health care workers and patients from infective agents in either a recognized or unrecognized source. How can we protect ourselves and our patients? Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Universal Precautions • Hand hygiene – Alcohol based hand rub – Hand washing • Personal protective equipment – Gloves – Protective eyewear – Masks – Clothing • Disposal of sharps and contaminated waste Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Transducer Hygiene  Remove all gel  Intact skin • Wipe with alcohol cloth and allow to dry - For example Isowipes  Broken skin/open wounds/body fluids • Chemical disinfection - For example Milton Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Transducer Hygiene • Open wounds and broken skin: – Require transducer cover such as Tegaderm – Sterile gel • Biopsies, FNA and intra operative ultrasound: – Require sterile technique – Sterile transducer cover – Sterile gel • Be aware of patients with latex allergy (gloves and probe covers) Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Intra cavity Transducers • TV / TR scanning • Should be covered wile scanning – special cover • Should be disinfected after the procedures with special disinfection device Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Work related musculoskeletal disorders (WRMSD) Persistent pain and discomfort in muscles, tendons and soft tissues that arise from work related activities • Why? – – – – – – – Awkward and sustained posture Twisting of the neck and trunk Arm abduction Excessive force, sustained pressure Assisting with patient movements Insufficient work breaks Poor equipment design Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae WRMSD • Areas affected – Shoulder, neck, upper and lower back, upper arm, eyes & wrist • Symptoms – Aching, stiffness, burning, pain, tingling, cramping and numbness • Results in – Weakness, reduced range of movement, loss of function Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae WRMSD - Injury Prevention • Ergonomically designed equipment • Posture • Ask the patient to move close to you • Lower the bed height to reduce arm abduction • If resting arm on patient, seek permission • Take breaks • Stretch regularly and maintain good fitness Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Questions??? Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Review questions: • What are the advantages of US vs CT imaging? • If a patient after lying on the bed for an abdominal ultrasound suddenly jumps up a attempts to leave the exam room, what would you do? • What are the 2 main biological effects of US? Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Quiz Why are universal precautions important? a) b) c) d) Because the University says so To minimise risk to the patient To prevent cross infection To alleviate anxiety in the patient Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae Quiz Identify which actions reduce WRMSD: a) b) c) d) e) f) g) Allow the patient to lie comfortably Stand for long periods without moving Move the patient closer to you Raise the height of the bed Run a marathon Perform a stretching routine Take regular breaks Course: FRD3061 Medical Imaging Science and Methods 2Ultrasound 1 Lecture :Basic Scanning Practice fchs.ac.ae