Non-invasive is a descriptive term for a procedure that
does not require an instrument or device to be inserted
into the body (through the skin or through a body
opening) for diagnosis or treatment. Non-invasive
procedures are contrasted with invasive procedures
such as open surgery. However, there are also
minimally invasive procures such as needle injections
and small incisions.
An ultrasound is non-invasive.
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The three areas of non-invasive procedures include imaging of the body for diagnosis
(e.g., x-rays), palpating tissues of the body (e.g., feeling the abdomen to detect organ
enlargement and/or identify the source of pain), and visual examinations (e.g., skin
exam). Examples on non-invasive procedures include placing a medicated patch onto the
skin, taking somebody's blood pressure, taking a pulse, listening to breath sounds,
hearing tests, vision tests, measurement of height and weight, use of a cast or splint, and
many others.

X-rays are traditionally considered non-invasive because no skin break or opening of a
body part is required. However, the x-rays do technically pass through the skin. Similarly,
CT scanning and magnetic resonance imaging (MRI) scans are both non-invasive. CT
(computerized tomography) scanning is an advanced imaging technique that uses x-rays
and computer technology to produce more clear and detailed pictures than a traditional x-
ray. MRI scans produce extremely detailed pictures of the inside of the body by using
very powerful magnets and computer technology.

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Ultrasound scanning is also non-invasive. Ultrasound scanning is a
procedure that uses high-frequency sound waves to produce
images of internal body structures. Non-invasive also means not
tending to spread, enter, or intrude into, through, or throughout
something (such as healthy tissue). This form of the term is
frequently used in regards to cancer if it does not spread. Cancer is
any of a large group of malignant diseases characterized by an
abnormal, uncontrolled growth of new cells in one of the body
organs or tissues. The opposite of non-invasive is invasive. Non-
invasive comes from the Latin word "non" meaning "not," the Latin
word "in" meaning "within," and the Latin word "vadere" meaning "to
go." Put the words together and you have "not to go within."