Radiology and Nuclear Medicine - Study Guide

Key Concepts

1. Introduction to Medical Imaging

Radiology: A medical specialty that uses imaging techniques (like X-rays, CT scans, MRI, ultrasound) to diagnose and treat diseases seen within the body.

Nuclear Medicine: A medical specialty that uses small amounts of radioactive materials (radiopharmaceuticals) to diagnose and treat a variety of diseases, often by showing organ function and structure.

2. Common Imaging Modalities

X-ray (Radiography):

Uses electromagnetic radiation to create images of bones and some soft tissues.

Radiopaque: Substances that absorb X-rays (appear white, e.g., bone, metal, contrast).

Radiolucent: Substances that allow X-rays to pass through (appear dark, e.g., air, fat).

Computed Tomography (CT Scan):

Uses a series of X-ray images taken from different angles and computer processing to create cross-sectional (slice) images of the body.

Excellent for bone, soft tissue, and blood vessels.

Magnetic Resonance Imaging (MRI):

Uses a strong magnetic field and radio waves to create detailed images of organs and soft tissues.

Does not use ionizing radiation. Excellent for brain, spinal cord, joints, and soft tissues.

Ultrasound (Sonography):

Uses high-frequency sound waves to create real-time images of internal organs, blood vessels, and structures.

No radiation involved. Commonly used for obstetrics, abdominal organs, and vascular studies.

Nuclear Medicine Scans (e.g., Bone Scan, Thyroid Scan):

Involves injecting a small amount of radioactive tracer into the bloodstream.

The tracer accumulates in specific organs or tissues, and a special camera detects the emitted radiation to create images showing function.

Positron Emission Tomography (PET Scan):

A type of nuclear medicine imaging that uses a radioactive tracer (often a glucose analog) to show how organs and tissues are working.

Often combined with CT (PET-CT) for both functional and anatomical information. Primarily used in oncology, neurology, and cardiology.

3. Contrast Media

Substances (e.g., iodine-based, barium, gadolinium) used to enhance the visibility of structures or fluids in medical imaging.

Administered orally, rectally, or intravenously.

4. Radiation Safety

Dosimetry: Measurement of radiation dose.

ALARA: "As Low As Reasonably Achievable" - principle for minimizing radiation exposure.

5. Common Medical Terms and Procedures

Angiography: X-ray imaging of blood vessels using contrast dye.

Arteriography: Imaging of arteries.

Venography: Imaging of veins.

Mammography: X-ray imaging of the breast to screen for breast cancer.

Fluoroscopy: Real-time X-ray imaging, often used for guiding procedures.

Scintigraphy: General term for nuclear medicine imaging.

Radiopharmaceutical: A radioactive drug used in nuclear medicine.

Radioisotope: A radioactive form of an element.

Uptake: The absorption of a radiopharmaceutical by an organ or tissue.

Hot Spot: Area of increased radiopharmaceutical uptake (e.g., tumor, infection).

Cold Spot: Area of decreased radiopharmaceutical uptake (e.g., necrosis, cyst).

Radiologist: Physician specializing in interpreting medical images.

Nuclear Medicine Physician: Physician specializing in nuclear medicine.

Sonographer: Technician who performs ultrasound exams.

Technologist (Radiologic, Nuclear Medicine): Professionals who perform the imaging procedures.

6. Key Combining Forms, Prefixes, Suffixes

Combining Forms:

ech/o, son/o: sound

fluor/o: luminous, fluorescence

mamm/o: breast

nucle/o: nucleus

radi/o: radiation, radius

scint/i: spark, scintillation