Intro Into Rad Ch 1

Institutional Context and Course Administration

  • Course Title: Introduction to Radiologic Sciences and Patient Care (Chapter 1)

  • Instructor: Jody Nutt, MS, RT(R)(T)

  • Department: Department of Medical Imaging & Radiation Sciences

  • Institution: Arkansas State University

Fundamental Concepts and Terminology

  • Radiology:

    • A specialized branch of medicine that deals with radioactive substances, radiant energy, and the diagnosis and treatment of disease using both ionizing and nonionizing radiation.

  • Radiography:

    • The process of making records, known as radiographs, of internal structures of the body.

    • Achieved by passing x-rays or gamma rays through the body to act on a specially sensitized film or a digital imaging plate/system.

    • In a diagnostic radiography department, images are created using x-rays that pass directly through the body.

  • Radiograph:

    • The physical or digital image produced on a sensitized film or plate by x-rays.

  • Radiologic Technologist / Radiographer:

    • A general term applied to individuals qualified to use x-rays (radiography) or radioactive substances (nuclear medicine) to produce images of internal body structures for physician interpretation.

    • Also classified as a healthcare professional who creates medical images of the body to assist healthcare providers in diagnosing and treating illness and injury (diagnostic radiology).

  • Radiologist:

    • A physician with specialized medical training in the field of diagnostic imaging.

    • Specializes in using roentgen rays and other forms of radiation to interpret diagnostic examinations and perform medical procedures to aid in patient diagnosis and treatment.

  • Radiologist Assistant (RA):

    • An advanced-level radiographer who expands the clinical capacity of the radiologist within the diagnostic imaging environment, directly enhancing patient care.

    • Functions under the direction and supervision of a radiologist to perform a wide variety of advanced patient care procedures.

    • Evaluates acquired images for technical completeness and diagnostic quality, reporting clinical observations back to the radiologist.

    • Performs advanced fluoroscopic examinations, including gastrointestinal (GI) studies, myelograms, arthrograms, and central venous line placements.

    • Qualified to administer contrast media and general medications.

  • Radiation Therapy:

    • The medical application of ionizing radiation to treat disease, specifically malignant cancerous tumors.

    • Utilizes very-high-energy x-rays within a dedicated radiation therapy department.

  • Radiation Therapist:

    • A specialized radiologic technologist responsible for administering a planned course of prescribed ionizing radiation treatments.

    • Employs high-technology therapeutic equipment and accessories to deliver treatments according to the precise prescription and instructions of a radiation oncologist.

  • Radiologic Technology:

    • The study and practice of diagnostic imaging methods to produce visualization of anatomical structures, functional organs, or biological processes within the body.

ARRT Recognized Disciplines

  • The American Registry of Radiologic Technologists (ARRT) formally recognizes the following distinct disciplines within the radiologic technology profession:

    • Radiography

    • Nuclear medicine technology

    • Radiation therapy

    • Cardiovascular-interventional radiography

    • Mammography

    • Computed Tomography (CT)

    • Magnetic Resonance Imaging (MRI)

    • Quality management

    • Sonography

    • Vascular sonography

    • Breast sonography

    • Bone densitometry (BD)

    • Radiologist assistants

Specialized Imaging Modalities

  • Cardiovascular Interventional Technology:

    • A subspecialty of radiology in which radiographers specialize in performing diagnostic radiologic examinations of the cardiovascular system using iodinated contrast media.

    • Focuses on minimally invasive diagnostic and therapeutic procedures performed under image guidance.

  • Mammography:

    • A subspecialty in radiology dedicated to obtaining images of breast tissue and surrounding musculature.

    • Utilized for diagnostic and preventive purposes:

    • Screening examinations

    • Diagnostic examinations

    • Image-guided biopsies

  • Bone Densitometry (BD):

    • A technique used to measure Bone Mineral Density (BMD).

    • Utilizes two x-ray beams with differing energy levels.

    • Soft tissue absorption is mathematical subtracted from final data to accurately calculate actual bone density.

  • Computed Tomography (CT):

    • A medical imaging method that measures x-ray attenuation/absorption to generate detailed soft-tissue images of internal organs.

    • Records a predetermined plane in the body using a rotating x-ray beam that is measured, recorded, and processed by a computer to display images on a monitor in various sectional planes.

  • Nuclear Medicine:

    • A branch of radiologic technology that uses radioactive materials for diagnostic or therapeutic purposes.

    • Patients are injected with a radionuclide, and the absorption/distribution of this nuclide is recorded into a final image.

    • Uses radioactive substances that emit gamma radiation directly from their atomic nuclei.

  • Magnetic Resonance Imaging (MRI):

    • Utilizes a powerful magnetic field combined with radiofrequency waves (radio waves) and computer processing to create sectional soft-tissue images of body anatomy.

  • Diagnostic Medical Sonography:

    • Visualization of internal body structures by transmitting pulses of high-frequency sound (ultrasound) waves into tissue and recording the returning reflections/echoes.

Career Expansion and Employment Opportunities

  • Commercial Firm Roles:

    • Sales

    • Applications Specialists

    • Field Service Engineering

  • Educational Positions:

    • Clinical Instructor: Focuses on teaching students primarily on a one-on-one basis in clinical settings; fulfilled by staff technologists or faculty members.

    • Didactic Faculty Member: Teaches students directly through formal classroom lectures and laboratory learning activities.

    • Clinical Coordinator: Combines didactic or clinical teaching responsibilities with administrative duties in overseeing clinical education facilities and assignments.

    • Program Director: Holds administrative responsibility for the entire educational program alongside teaching obligations. Requires a minimum of a Master's degree, with advanced coursework in educational principles being desirable.

  • Management and Administrative Roles:

    • Positions include Supervisor, Chief Technologist, and Department Director.

    • While no universal minimum education requirement exists, a Bachelor's degree is typically preferred.

    • Professional expertise in multiple modalities (multimodality) is considered a major candidate asset.

The Health Care Team

  • Healthcare delivery involves a collaborative team structure consisting of:

    • Physicians

    • Nurses

    • Diagnostic Services

    • Therapeutic Services

    • Health Information Services

    • Additional Allied Health Professions:

    • Dental health

    • Dietetics

    • Psychosocial health care

    • Emergency care

Historical Foundations of Radiology

  • Discovery Date: November 8, 1895.

  • Discoverer: Wilhelm Conrad Roentgen (Röntgen).

  • Discovery Context: While conducting experiments with a cathode ray tube, Roentgen observed the illumination/fluorescence of a nearby screen.

  • First Radiograph: Famous for producing the world's first radiographic image, which was of his wife's hand (Hand mit Ringen).

  • Nomenclature: Coined the term "x-rays" because the letter "x" is the mathematical symbol used for an unknown variable.

  • Honors: Received the very first Nobel Prize in Physics.

  • Death: Wilhelm Conrad Roentgen died in 1923 from colon cancer.

Physics of Radiation and Energy Forms

  • Nature of Radiation:

    • Radiation is energy transmitted by waves through space or through a material medium (matter).

    • Radiation has permeated the universe since the beginning of time and is a natural constituent of life.

    • It is necessary for life, though exposure often evokes fear.

  • Energy in Medicine:

    • Multiple forms of energy are used in medicine to construct images of anatomic structures or physiological functions needed for proper disease diagnosis and therapy.

    • All these energy forms fall under the classification of radiation because they travel through matter.

  • Ionization:

    • The process by which a neutral atom gains or loses an electron, thereby acquiring a net electrical charge.

    • Higher-energy radiation forms, such as x-rays, possess sufficient energy to ionize biological atoms.

    • Ionization disrupts the atomic composition of matter, which can subsequently alter or damage biological life processes.

    • Specialized radiation protection measures must be implemented to prevent excessive ionizing radiation exposure to patients and personnel.

  • Mechanical Energy (Sound):

    • Sound represents a form of mechanical energy transmitted through matter.

    • Returning sound waves are recorded to reconstruct images.

    • Sound waves are classified as nonionizing radiation.

    • Utilized clinically in Diagnostic Medical Sonography.

  • Nuclear Energy:

    • Energy emitted directly from the nucleus of an atom.

    • Nuclear medicine technology utilizes this energy to image anatomic structures and physiological actions by introducing radioactive substances that emit gamma radiation from their nuclei.

  • Electromagnetic Energy:

    • Light is a critical form of electromagnetic energy used in medical scopes to visually inspect internal body cavities.

    • X-rays are a human-made form of electromagnetic energy created when high-speed electrons are suddenly decelerated or stopped.

    • X-rays permit non-surgical visualization of internal anatomical structures that were historically visible only during surgical procedures.

The Electromagnetic Spectrum

  • Wavelength Metrics (m\text{m}):

    • Spans from 106 m10^6\,\text{m} down to 10−12 m10^{-12}\,\text{m}.

    • Quantitative scale steps: 106 m10^6\,\text{m}, 103 m10^3\,\text{m}, 1 m1\,\text{m}, 10−3 m10^{-3}\,\text{m}, 10−6 m10^{-6}\,\text{m}, 10−9 m10^{-9}\,\text{m}, 10−12 m10^{-12}\,\text{m}.

  • Frequency Metrics (Hz\text{Hz}):

    • Spans from 10−15 Hz10^{-15}\,\text{Hz} up to 1024 Hz10^{24}\,\text{Hz}.

    • Quantitative scale steps: 10−15 Hz10^{-15}\,\text{Hz}, 10 Hz10\,\text{Hz}, 103 Hz10^3\,\text{Hz}, 106 Hz10^6\,\text{Hz}, 109 Hz10^9\,\text{Hz}, 1012 Hz10^{12}\,\text{Hz}, 1015 Hz10^{15}\,\text{Hz}, 1018 Hz10^{18}\,\text{Hz}, 1021 Hz10^{21}\,\text{Hz}, 1024 Hz10^{24}\,\text{Hz}.

  • Energy Metrics (eV\text{eV}):

    • Spans from 10−12 eV10^{-12}\,\text{eV} up to 109 eV10^9\,\text{eV}.

    • Quantitative scale steps: 10−12 eV10^{-12}\,\text{eV}, 10−9 eV10^{-9}\,\text{eV}, 10−6 eV10^{-6}\,\text{eV}, 10−3 eV10^{-3}\,\text{eV}, 103 eV10^3\,\text{eV}, 106 eV10^6\,\text{eV}, 109 eV10^9\,\text{eV}.

  • Spectral Classifications (ordered from longest wavelength/lowest energy to shortest wavelength/highest energy):

    • Radio waves

    • Television signals

    • Radar

    • Magnetic Resonance Imaging (MRI)

    • Heat / Infrared radiation

    • Visible light spectrum (Red, Orange, Yellow, Green, Blue, Violet)

    • Ultraviolet light

    • X-rays (Diagnostic x-rays and Therapeutic x-rays)

    • Gamma rays

    • Cosmic rays