Chapter 20 - Radiology and Nuclear Medicine

Characteristics of X-Rays

-Expose photographic plates

-Penetrate substances

-Invisible

-Travel in straight lines

-Scatter

-Ionization

Diagnostic Techniques

-X ray studies -> digital radiography, CT, contrast studies

-Fluoroscopy

-Digital imaging techniques

-Interventional radiology

-Ultrasound

-MRI or MR

Digital Radiography

Uses digital x-ray detectors instead of photographic film

Contrast Studies

-Barium sulfate -> upper or lower GI

-Iodine compounds -> angiography, arthrography, cholangiography, digital subtraction angiography, hysterosalpingography, myelography, pyelography

Radionuclides/Radioisotopes

Alpha particles, beta particles, gamma rays

Nuclear Medicine Tests

In vitro: test tube

In vivo: in the body

Half-Life

Time required to lose half of its radioactivity (disintegration)

Analysis of Blood and Urine

Radioimmunoassay (RIA) uses radioactive chemicals and antibodies to detect hormones and drugs in the patient's blood

In vivo

Radiopharmaceutical

-Labeled compound concentrates in an organ

-Radioactive substance given directly to patient to evaluate organ function or image

-In vivo

Scintiscanner

-Gamma camera detection instrument produces picture (scintiscan)

-Radioactive substance given directly to patient to evaluate organ function or image

-In vivo

Radioprocedures Using Radionuclides

-Bone scan

-Lymphoscintigraphy

-PET scan

-CT scan

-SPECT

-Technetium Tc-99m sestamibi (Cardiolite) scan

-Thallium scan

-Thyroid scan

PET Scan

-Positron emission tomography

-Radioisotopes (emission of positrons)

-IV injection

-High resolution images of body function and metabolism

-Concentrates radioisotopes in tissues where the radionuclide is/isn't being metabolized

-Useful in treating stroke, epilepsy, Alzheimer disease, brain tumors, abdominal and pulmonary malignancies

SPECT

-Single-photon emission computed tomography

-IV injection of radioactive tracer (gamma rays)

-Computer reconstruction of 3D images

-Detects liver tumors, cardiac ischemia, diseases on bone and spine

Interventional Radiology

-Treats patients using minimally invasive techniques as an alternative to surgery

-"Pinhole surgery"

Radioactive Decay

-Nucleus is unstable and will decay into a more stable atom

-Spontaneous

Radioactive Decay Types

Alpha particle, beta particle, gamma ray

Radionuclide (Radioisotope)

Substance that gives off high-energy particles or rays as it disintegrates

In Vitro

Test tube

In Vivo

In the body

Bone Scan

-Nuclear scanning test that identifies new areas of bone growth or breakdown

-Evaluates bone damage, metastasized cancer, monitor infection and trauma

Lymphoscintigraphy

-Nuclear medicine test

-Locate lymph nodes and identify spread of caner

-Locate sentinel nodes for surgical removal

-Diagnose lymph system disease conditions

PET-CT Scan

-Combines PET and CT techniques to have a more accurate image

-Used with surgical planning, radiation therapy, and cancer staging

PET-MRI Scan

-MRI combined with PET scan

-MRI -> better for soft tissue

-PET -> evaluates function imaging

-Used in oncology, cardiology, and neurology mainly

99M Technetium Sestamibi (Cardiolite) Scan

-Uses a tracer to produce images of heart muscle

-When combined with an exercise test it helps determine if areas of the heart are not receiving enough blood

-Diagnosis of coronary heart disease

Thallium Scan

-Thallium-201 injected via IV to evaluate heart (myocardial) perfusion

-Lack of uptake of thallium-201 in areas of the heart with infarcted or scarred myocardium

Thyroid Scan

-Radioactive iodine (iodine-123) is given orally

-Thyroid scanned to determine size and shape of glands

-Another test uses radioactive technetium IV to look for hyperfunctioning thyroid nodules accumulating more radioactivity (hot spots) and were there is no concentration (cold spots, thyroid cancer)

Obstructing the passage of x-rays:

A. Radiopaque

B. Radiolucent

C. Radioisotope

D. Radiopharmaceutical

A. Radiopaque

Which of the following is a handheld device that sends and receives ultrasound signals?

A. Gamma camera

B. Roentgenology

C. Radioisotope

D. Transducer

D. Transducer

Which term refers to movement away from the midline of the body?

A. Adduction

B. Abduction

C. PA

D. Inversion

B. Abduction

Which term refers to a patient lying on the back?

A. Prone

B. Supine

C. Flexion

D. Decubitus

B. Supine