Medical Imaging Technologies

X-RAYS Lose doses of radiation used to make images that can diagnose problems/ diseases in the body As the radiation penetrates the body, it is absorbed in varying amounts by different body tissues depending on the tissue's composition of air, water, blood, bone, or muscle. Bones, for example, absorb much of the X-ray radiation while lung tissue (which is filled with mostly air) absorbs very little, allowing most of the X-ray beam to pass through the lung. Due to the differences in their composition (and, therefore, varying degrees of penetration of the X-ray beam), the lungs, heart, aorta, and bones of the chest each can be distinctly visualized on the chest X-ray. The X-ray film records these differences to produce an image of body tissue structures and these are shadows seen on the X-ray. The white shadows on chest X-ray represent more dense or solid tissues, such as bone or heart, and the darker shadows on the chest X-ray represent air filled tissues, such as lungs.

When are X rays used? CHEST PROBLEMS BROKEN BONES CHEST: diagnose problems like TB, pneumonia, heart problems, asthma, cysts, cancers CHEST PROBLEMS BROKEN BONES

X-RAYS Advantages Disadvantages Inexpensive Widely available Fast and easy (good for emergency diagnosis) May increase chance of cancer Not very sensitive (for soft tissues)

Computerized Tomography (CT) Many X-rays images used to create cross sectional or 3D images of internal organs or structures to identify abnormalities Dye may be used Like a loaf of bread – creates cross sectional slices Dye injected into spinal fluid to improve contrast If X ray shows problems, a CT scan is done to confirm diagnosis

When is CT used? HEAD INJURIES TUMOURS INFECTIONS Stages of osteoporosis INFECTIONS: in lungs HEAD INJURIES TUMOURS INFECTIONS

Computerized Tomography (CT) Advantages Disadvantages Painless More accurate than X rays Image bone, soft tissue, and blood vessels at the same time Fast Real-time imaging Reaction to dye Radiation is used Pregnant and obese people cannot use it Real-time imaging: can do other procedures with it

Magnetic Resonance Imaging (MRI) Uses a magnetic field to take many pictures inside the body to see if there is anything abnormal.

When is MRI used? TUMOURS TORN ACL SPINAL CORD INJURIES Look at abdominal organs, reproductive organs, breasts, blood vessels, tumours TUMOURS TORN ACL SPINAL CORD INJURIES

Magnetic Resonance Imaging (MRI) Advantages Disadvantages Very accurate Painless Doesn’t use radiation Expensive Patient must lie very still (or be sedated or anesthesized) Takes a long time Patients with cardiac pacemaker, metal implants or chips cannot use it

Uses sound waves to get an image from inside the body Ultrasound Uses sound waves to get an image from inside the body

When is ultrasound used? Echocardiography: evaluates the heart, the heart's valve function, and blood flow through them. It also evaluates the heart wall motion and the amount of blood the heart pumps with each stroke. PREGNANCY ECHOCARDIOGRAPHY BLOOD CLOTS

Ultrasound Advantages Disadvantages No known risks Live images Widely available ACCURACY DEPENDS ON OPERATOR Can’t penetrate too deep (obesity if a problem) Poor images when gas is present Gas: in lungs or intestines( can’t see organs behind it)

MICROSCOPY Allows us to see organisms/objects that we cannot see with our eyes alone

Light Microscopy Light is passed through or reflected from a specimen through lenses to magnify it.

Uses: (1) Look at cells (2) Diagnose Infections ONION SKIN CELLS RED BLOOD CELLS Uses: (1) Look at cells (2) Diagnose Infections

Light Microscopy Advantages Disadvantages Relatively cheap Live or dead specimens Natural colour can be kept Can only magnify up to 2000x Stains kills specimen

Electron Microscopy A beam of particles called electrons are used to illuminate the specimen and magnify it

When is electron microscopy used. To study microscopic organisms When is electron microscopy used? To study microscopic organisms. Examples: CANCER CELLS HIV VIRUS RED BLOOD CELLS SWINE FLU VIRUS

Electron Microscopy Advantages Disadvantages Can magnify up to 2,000,000x! $$$$$$ Specimens must be dead Preparation takes a long time