MEDICAL INTERVENTIONS MRS. STEWART CENTRAL MAGNET SCHOOL Diagnostic Imaging

X-Ray Noninvasive produces images of the inside of the body to help diagnose medical conditions. Use a form of electromagnetic radiation that is sent through the body.

X-RAYS Dense structures – eg: bone - block most of the X-ray particles and appear white. Metal or contrast media (special dye used to highlight areas of the body) will also appear white. Structures containing air will appear black Muscle, fat, and fluid will appear gray.

X-Ray Produces 2D images. Examines bones, teeth, lungs, breasts, heart, blood vessels, and the digestive tract. Uses ionizing radiation which can increase risk of developing cancer. ©iStockphoto.com

X-Ray – The Procedure X-ray is performed by a machine that sends individual X-ray particles, called photons, through the body.  The photons pass through the body and the resulting images are recorded on a computer or special film. ©iStockphoto.com

Advantages and Disadvantages Advantages  Quick  painless  noninvasive test  Relatively inexpensive  Cheaper than a CT or MRI – cheapest test that takes pictures of the body Disadvantages  Small amount of radiation exposure  Contrast materials sometimes used might produce an allergic reaction

CT Scan – Computerized Tomography Also called Computerized Axial Tomography (CAT Scan). Used to produce images of the inside of the body to help diagnose and treat medical conditions. A series of X-ray views taken from many different angles are combined to produce cross-sectional images of the bones and soft tissues inside your body.

CT Scan Produces cross-sectional images of the body give 3D views. Examines the chest, abdomen, pelvis, spine, and other skeletal structures. Uses ionizing radiation which can increase your risk of developing cancer. ©iStockphoto.com

CT Scan – The Procedure CT scan is performed inside a large tube that looks like a large doughnut standing on its side, and the person lies on the table in the center.  The X-ray tube rotates around the body.  The table slowly moves through the inside of the machine.  Each rotation yields several images of thin slices of the body. ©iStockphoto.com

Advantages and Disadvantages Advantages  Painless  Noninvasive  Accurate, fast and simple  Able to image bone, soft tissue, and blood vessels all at the same time  Can be performed if patient has an implanted medical device of any kind Disadvantages  Small amount of ionizing radiation exposure  Contrast materials sometimes used might produce an allergic reaction  More expensive than Xray  Large patients may not fit

MRI – Magnetic Resonance Imaging Used to produce 3D images of the inside of the body Unlike X-rays and CT scans, which use radiation, MRI uses powerful magnets and radio waves. Detailed and best images produced of soft tissue

MRI Produces cross-sectional images of the body to create 3D views. Used to examine the brain, spine, joint, abdomen, blood vessels, and pelvis. Is very safe as the magnetic field itself does not hurt people (unless they have certain types of metal implanted in their body).

MRI brain scan

MRI – The Procedure MRI scan is performed inside a large magnet, and the person lies on the table in the center.  The machine scans the body by turning small magnets on and off.  Radio waves are sent into the body.  The machine then receives returning radio waves and uses a computer to create pictures of the part of the body being scanned. ©iStockphoto.com

Advantages and Disadvantages Advantages  Noninvasive test  poses almost no risk when safety guidelines are followed  Does not expose to ionizing radiation  Images of the soft tissue structures of the body are more likely to identify and accurately characterize diseases than other imaging methods  Contrast materials less likely to produce an allergic reaction than those used in x-rays and CT scans Disadvantages  Not usable for any patient with metal in their body  Implanted medical devices (pacemakers) may malfunction  Very slight risk of an allergic reaction if contrast material is injected  Confined space may induce panic or feelings of claustrophobia in some patients  Large patients may not fit  Most expensive imaging

CT vs. MRI vs. XRAY CT/MRI provide a cross-sectional view creating a 3D image; XRAY is only 2D CT is faster and less expensive MRI provides a more detailed view than a CT for soft tissue CT is safest to use on patients when medical history is unknown CT is quicker than an MRI

Bone Scan Noninvasive medical test used to produce images of the bones that help diagnose and track several types of bone disease. Bone scan is a nuclear imaging test.

Bone Scan Produces 2D images of the entire skeleton. Used to detect abnormalities. Tiny amounts of radioactive tracers (radionuclides) are injected into the body  These will be absorbed by bone cells that are doing the most growth and metabolism  These tracers will cause dark spots on the scan where they are absorbed most ©iStockphoto.com Notice how the darkest areas are those experiencing the most growth in this adolescent – right on the growth plates

Bone Scan Identifying a Tumor on Shoulder

Bone Scan – The Procedure An injection of tracers is administered to the patient and allowed to circulate and be absorbed by the bones. Once absorbed, the patient lies on a table while a machine passes a gamma camera over the body to record the pattern of tracer absorption by the bones. Radiologists look for abnormal bone metabolism on the scan, areas that show up as darker or lighter where tracers have or have not accumulated.

Advantages and Disadvantages Advantages  Noninvasive  Extremely sensitive to abnormalities and variations in bone metabolism  Can scan the entire skeleton Disadvantages  Cannot determine cause of bone metabolism abnormalities  Tracers used produce a small amount of radiation exposure

PET Scan A positron emission tomography (PET) scan is an imaging test that uses a radioactive substance called a tracer to look for disease in the body. A PET scan shows how organs and tissues are working. Sugar and radioactive tracers are injected together. A PET scan can reveal the size, shape, position, and some function of organs. This test can be used to:  Check brain function  Diagnose cancer, heart problems, and brain disorders  See how far cancer has spread  Show areas in which there is poor blood flow to the heart

PET Scan

Application Questions A patient enters a hospital after hitting her head in a car accident. She is diagnosed with a fractured skull but has other symptoms that she is suffering from brain damage. What technology should be used to confirm this diagnosis?  Does it make a difference if I tell you this patient has screws in her left knee after a bad break as a kid?

Application Questions Design a patient situation where it would be inappropriate to use an MRI scan as a diagnostic tool  Besides metal in their body

Application Questions Evaluate the Dr’s reason for using a combination of X-rays, CT scans, bone scans and MRI scans when diagnosing Mike’s osteosarcoma (bone cancer).

Application Questions Why do you think patient’s are often fearful of having an MRI or CT scan?

Application Questions MRI UltrasoundCT