Senior Science
Medical Technology- Bionics
Non-invasive medical techniques
Non-invasive medical procedures are those that do not involve tools that break
or invade the skin or physically enter the body cavity. Non-invasive techniques
are used to recognize injury and disease. Examples of non-invasive techniques
include x-rays, MRI, Holter monitor, ultrasounds and thermography.
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Advantages
No risk of infection
No risk of loss of blood
No hospital stays, more beds
Less cost due to no hospital
stay and sterilisations
No pain or discomfort
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Disadvantages
Radiation from x-rays can be
damaging and may cause cancer
if overexposed
Resolution and angles of imaging
can be limited and may reduce
the reliability of results
Minimally invasive medical techniques
Minimally invasive techniques are those that are performed by making the
smallest convenient opening in the skin using specialised techniques, to repair
injuries, problems or remove tissue, a small camera is also inserted into the hole
so the surgeon can see what to do. Minimally invasive techniques attempt to
reduce the trauma to a patient throughout treatment. These are usually small
incisions measuring a few centimetres or less. Minimally invasive surgery can be
performed both on an “inpatient” (stay in the hospital) and “outpatient” (go home
the same day) basis.
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Advantages
Less risk of infection than with
open surgery
Smaller incisions
Less pain after the operation
Less complications with healing
wounds
Not as much scarring
Quicker recovery time
Reduction of blood loss
Reduced health care costs
Eliminates potential
complications
Less time and cost for hospitals
than for longer stays with open
surgery
Earlier return to work
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Disadvantages
Minimally Invasive operations
may take longer to perform in
some situations
Sometimes a doctor may need
to change from a minimally
invasive to an open surgery if
complications occur
Disadvantages for the surgeon can
include:
 Restricted vision
 Difficulty in handling the
instruments
 Restricted mobility and
 Problems with hand-eye
coordination
X-Rays
German Physicist Wilhelm Roentgen discovered x-rays in 1895 and this
revolutionary discovery meant that we could see inside a human body without the
need for cutting it open. Their high energy means that X-rays can pass through
skin and muscle. Dense tissues like cartilage and bone absorb them. This
produces an image on photographic film, which can show damage that is
otherwise hidden to the naked eye. Not only can damage to bones and joints be
detected but also things such as cancers and tuberculosis as they are more
dense and x-rays will not pass through them, they will show up as shadow areas
or masses of solid material where there shouldn’t be.
This chest x-ray shows a shadow over the left lung,
which was later diagnosed as lung cancer
http://www.emedicinehealth.com/images/4453/4453-13251-15405-20689.jpg
This is an x-ray which shows a broken humorous
www.campbell.amedd.army.mil/periop/ortho.shtml
Advantages
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No risk of infection as skin is not
penetrated
Reduction of need for invasive
surgery and techniques
Can detect problems with bones
and joints as well as detecting
breast cancer and tuberculosis
X-rays have a higher resolution
than ultra sounds
No blood loss
Disadvantages
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The 2 dimensional nature of xrays means many images may b
needed from different angles
As x-rays are electro magnetic
rays over exposure can be harmful
and possibly cause cancer and
therefore use is limited
Ultrasounds
Ultrasounds allow imaging of body parts using high-pitched sound waves. They
use these sound waves that are above the range of human hearing to create an
image of organs within the body. Sound waves are projected onto tissues and are
reflected off internal body structures and back to the ultrasound machine. The
reflected sound waves are analysed by computer and turned into pictures.
Ultrasounds can measure foetal size, the amount of amniotic fluid, estimate
foetal gestational age, identify multiple foetuses, some foetal abnormalities
such as microcephaly or Down Syndrome, and identify the location of the
placenta. It can also be used for the treatment of hypothermia and in noninvasive surgery. In these uses the extent and strength of the ultrasound signal
are carefully controlled.
These pictures show the sometimes unclear
nature of ultrasound pictures
This is an ultrasound of the head of a healthy
unborn boy at 20 weeks
http://www.whitedoom.com/Baby/ultrasounds.html
This shows the hand of an unborn girl
www.peteandjane.com/jessica/gallery/photos.ph.com
Advantages
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The sound waves used in
ultrasounds are harmless to the
body
No risk of infection as skin is not
penetrated
Reduction of need for invasive
surgery and techniques
Ultrasound examinations are
usually quicker and less expensive
than CT or MRI
No harmful effects have been
detected
No bleeding or blood loss
Disadvantages
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Resolution of images is often
limited
Ultrasound cannot be used for
examinations of areas of the body
containing gas, such as the lung
and the digestive system because
gas reflects the sound very highly
Ultrasound does not pass well
through bone
Less clear pictures than X-rays,
CAT scans or MRI
Thermography: (digital infrared thermal imaging)
Medical thermography is a non-invasive, non-contact diagnostic technique, which
uses the heat from a human body to make a diagnosis of problems and
conditions. High-speed computers and very accurate thermal imaging cameras
detect the heat from a body, process and record the results into a computer
and create an image map. A doctor can then use the image map to decide if
abnormal hot or cold areas are present. These hot and cold areas, can relate to
a number of conditions. These include cancer, extra-cranial vessel disease (head
and neck vessels), neuro-musculo-skeletal disorders, arthritis and vascular
disease. Thermal imaging detects the increased heat associated with increased
vascularity of a majority of doubtful growths, and can sense a "thermal signal",
often years in advance of any mass that would be detected on an x-ray.
28 year old male with clinical left carpal
tunnel syndrome
http://www.meditherm.com/therm_page9.htm
This thermography screening shows high
temperatures in the right breast, which
was identified as a cancer
www.thermogramcenter.com/ Images.htm
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Advantages
Thermography is 100% safe
Pain free
No radiation exposure
Simple and less expensive than
the commonly used
mammography
More effective than
mammography in women under
50 years of detecting breast
cancer
No side effects
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Disadvantages
Can sometimes give false
positive results showing a
tumour where there is none
Can sometimes be
uncomfortable for the patient
MRI: Magnetic resonance imaging
Magnetic resonance imaging uses radiofrequency waves and a strong magnetic
field to provide extremely clear and thorough pictures of internal organs and
tissues. This method has demonstrated very valuable for the diagnosis of a wide
range of pathologic conditions in all parts of the body, including cancer, heart
and vascular disease, stroke, and joint and musculoskeletal disorders. It is the
most responsive exam for spinal and joint problems. MRI of the heart, aorta,
coronary arteries, and blood vessels is a quick tool for diagnosing coronary
artery disease and heart problems. Physicians can observe the size and
thickness of the chambers of the heart, and determine the degree of damage
caused by a heart attack or progressive heart disease. MRI works by
radiofrequency waves being directed at protons, the nuclei of hydrogen atoms,
in a strong magnetic field. The protons are first "excited" and then "relaxed,"
emitting radio signals that can be computer-processed to form an image. In the
body, protons are most abundant in the hydrogen atoms of water so that an MRI
image shows differences in the water content and allocation in a variety of body
tissues.
The light grey region in this 19 year old females
scan was diagnosed as a brain tumour which was then
removed
ampat.amu.edu.pl/przyp/case12/CASE12.HTM
This MRI scan showed a tumour developing on the end
of the femur (osteochondroma)
www.qldxray.com.au/.../ mri_gallery10.html
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Advantages
Images of the soft-tissue
structures of the body are
more detailed than with other
methods
Helps with early diagnosis and
evaluation of tumours
Less likely to produce an
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Disadvantages
There are many people who
cannot safely be scanned with
MRI because it uses large
powerful magnets (for example,
people with pacemakers)
MRI scans may require patients
to be still for extended periods
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allergic reaction than the
iodine-based materials used for
conventional x-rays and CT
scanning
Enables the detection of
abnormalities that might be
obscured by bone with other
imaging methods
Exposure to radiation is avoided
No radiation exposure
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of time from 20 minutes to 90
minutes or more. Even very
slight movement of the part
being scanned can cause
distorted images that have to
be repeated
Screws, plates, artificial joints
can distort images
Exams can be very expensive
Should not be used during the
early stages of pregnancy
MRI may not always distinguish
between tumour tissue and
edema fluid
Keyhole surgery:
Keyhole surgery is done under a general anaesthetic. This surgery involves a
technique in which short, narrow tubes (trochars) are inserted into the body
through small (less than one centimetre) incisions. Through these trochars, long,
narrow instruments are inserted. The surgeon uses these instruments to
manoeuvre, cut, and sew tissue. A camera is also put inside the body through an
incision near the belly button and linked to a monitor so the surgeon can see the
procedure.
A number of different procedures can be performed in this manner, including
gallbladder removal (this is called laparoscopic cholecystectomy), colon surgery
(or laparoscopic colectomy), appendicitis, cholecystitis and other complicated
abdominal problems.
Keyhole surgery requires different skills and training then open surgery and is
much more difficult and complex; therefore up to 20% of keyhole surgeries are
converted to open surgeries during the procedure.
The procedure of keyhole surgery,
incisions and placing of camera
www.umm.edu/surgeries/ laparoscopicsurgery_1.html
The scars left after keyhole surgery are
significantly than those after open
surgery
www.umm.edu/surgeries/ laparoscopicsurgery_1.html
Advantages of key hole surgery
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Much quicker recovery than from open surgery because of the less
invasive nature of the surgery
Because the surgeon creates only a few small incisions, pain after surgery
is generally reduced as compared with traditional surgery
Less wound and surgery complications than open surgery because the
wound is not as big as traditional surgery
Less risk of infection than with open surgery
Less gaping at the wound site as the wound is not as big
Less disruption to the organs of the body
Better cosmetic results (less scarring)
Less restriction of movement and quicker return to post operation
activities. Patients may be discharged within few hours of surgery and
resume their normal activities within 3-4 days after the operation
More free hospital beds due to earlier discharge then open surgeries
Saves hospital resources
Less tissue damage and blood loss
Often a better option for children as the reduction of pain is a big issue
when dealing with sick or injured children
Less post operation trauma because of the better cosmetic results
Even though the actual operation may cost more the overall cost after
hospital cost reduction is sometimes cheaper than open surgery.
There are also many benefits to the community because of the earlier return to
work for the patient and the early release from hospital these benefits are
mostly economical and include the cost of hiring extra staff and the loss of
production costs which are greatly decreased due to the quicker healing time of
keyhole surgery.
Books:
Vanessa Smith, Sandhya Ross, Ruth Miller and David Heffernan, Senior Science,
Science Press Marrickville 2001
World Book Encyclopedia 2000 volume 13, World Book Publishers 2000
World Book Encyclopedia 2000 volume 19, World Book Publishers 2000
World Book Encyclopedia 2000 volume 21, World Book Publishers 2000
Internet Sites:
http://www.rdradiology.com/ultra.html
http://www.bccresearch.com/editors/RC-140N.html
http://www.healthscout.com/ency/article/002269.htm
http://hsc.csu.edu.au/senior_science/core/bionics/9_3_5/935net.html#net2
http://www.mrcophth.com/commonultrasoundcases/principlesofultrasound.html
http://www.schoolscience.co.uk/content/4/biology/abpi/history/history10.html
http://www.babyzone.com/features/glossary/default.asp?TermID=50
http://www.breastthermography.org/FactsMyths.htm
http://www.gsmcweb.com/Breast%20Thermography.htm
http://www.foxvalleywellness.com/pages/thermography.cfm
http://www.radiologyinfo.org/content/mr_of_the_body.htm
http://www.ich.ucl.ac.uk/factsheets/families/F040282/#whatis
http://laparoscopicsurgeon-online.com/benefits_of_laparoscopy.htm
http://doctorndtv.com/feature/detailarchivefeature.asp?id=54
Pictures:
http://www.emedicinehealth.com/images/4453/4453-13251-15405-20689.jpg
www.campbell.amedd.army.mil/periop/ortho.shtml
http://www.whitedoom.com/Baby/ultrasounds.html
http://www.meditherm.com/therm_page9.htm
www.thermogramcenter.com/ Images.htm
www.qldxray.com.au/.../ mri_gallery10.html
www.ampat.amu.edu.pl/przyp/case12/
www.umm.edu/surgeries/ laparoscopicsurgery_1.html