Comprehensive Study Guide for Radiologic Technology and Health Care

The Science of Radiology and Historical Perspective

The medical science encompasses a wide array of subjects designed to explain the intricate workings of the human body. To effectively diagnose a patient, a medical practitioner must first possess a thorough understanding of how a fit and healthy body functions. The science of radiology is a specialized field within this discipline, which underwent a significant transformation starting in the late nineteenth century.

Historically, the discovery of x-rays offered immense hope to the scientific community, though the general public initially struggled to comprehend the phenomenon. Because x-rays cannot be perceived by the five human senses—sight, touch, taste, smell, or hearing—explaining their nature was inherently difficult. The discovery is credited to Wilhelm Conrad Roentgen, a German physicist at the University of Wurzburg, who encountered these "unknown types of rays" in $1895$ while experimenting with cathode rays. Cathode rays are composed of electrons, which carry a negative charge. Roentgen’s discovery was originally referred to as Roentgen Rays, an old term for what we now commonly call x-rays.

Simultaneous to Roentgen's work, other physicists made landmark contributions to the field. Antoine Henri Becquerel, a French physicist, utilized uranium salts to discover radioactivity. He found that uranium does not emit rays through light but rather due to its own instability. This state of radioactivity occurs when an element or material is unstable, caused by an imbalance of neutrons and protons within the nucleus, leading the atoms to become unstable. This process often involves transmutation, which is the changing of one chemical element into another through radioactive decay, nuclear bombardment, or similar processes. Marie Sklodowska-Curie, working with her husband Pierre Curie and Henri Becquerel, shared the Nobel Prize in $1903$ for the discovery of radioactivity phenomena. Marie Curie's work further defined the conversion of chemical elements via radioactive processes.

Technical Principles of Radiographic Imaging

Radiologic technology relies on the manipulation of specific technical factors to produce diagnostic images. One primary factor is $kVp$ (Kilovoltage Peak), which represents the quality of the x-ray beam. Adjusting the $kVp$ changes the number of shades of gray in the image and determines the beam's ability to penetrate tissues, soft objects, or metals. Furthermore, the $kVp$ level directly affects the radiation dose received by the Radiologic Technologist. In radiography, the term contrast refers to the density or degree of grayness between different areas of a radiographic image, and it is the primary element controlled or countered by $kVp$.

Another critical factor is $mAs$ (Milliampere-seconds), which represents the quantity of radiation. Increasing the $mAs$ increases the amount of photons produced, which in turn controls the density of the image. A higher number of photons results in a darker film. However, a higher $mAs$ also means a higher radiation dose for the patient, increasing the risk of biological damage. A successful radiograph must possess the proper density and contrast and must not be overexposed (too dark) or underexposed (too light). Many variables can affect these outcomes. Artifacts and image quality are assessed using tools like the light meter, which measures the output of a negatoscope (also known as a viewbox), the device that provides the white light used to view x-ray films.

Medical Application and Categorization of Radiation

Radiation is defined as energy that originates from a source and travels through space, possessing the ability to penetrate various materials. It is categorized into two main types: non-ionizing and ionizing radiation. Non-ionizing radiation includes radio waves, microwaves, infrared, visible light, and ultraviolet light. Microwaves with long wavelengths are typically used for food, while short microwaves are utilized in various technologies. Infrared radiation is associated with weather and temperature measurements. Ionizing radiation is produced by unstable atoms and includes electromagnetic radiation such as gamma rays and x-rays, as well as particulate radiation like alpha and beta particles.

Unstable atoms differ from stable ones because they possess an excess of energy, mass, or both. To reach stability, these atoms emit this excess, a process known as radioactive decay. Gamma radiation originates specifically from the nucleus of an atom and is used in radiation therapy and nuclear energy, often involving multi-million volts. X-rays, conversely, originate from the electronic part (the electron shells) of the atom where electrons interact. Ionization refers to the process of an atom gaining or losing electrons to acquire a charge.

Radiation is also ubiquitous in the environment as "background" radiation. This includes cosmic background radiation, which the Earth receives from outer space, and terrestrial background radiation originating from the Earth’s crust and living things. In medical imaging, radiation interacts with the body in three ways: absorption, scattering, and transmission. If radiation is absorbed and does not pass through the body, the patient receives a radiation dose. Dense organs may cause radiation to be either transmitted or scattered, the latter of which can contribute to blurry images on x-ray films.

Modalities in Diagnostic, Interventional, and Therapeutic Radiology

Radiology is broadly divided into three areas: diagnostic radiology (assessing disease), interventional radiology (intervening in disease processes, such as blockages in veins), and therapeutic radiology (treating patients). Medical imaging tests are non-invasive procedures that allow doctors to see inside the body to diagnose injuries or diseases without surgery. These tests help doctors obtain better views of organs, blood vessels, tissues, and bones; determine if surgery is necessary; and guide the placement of stents, catheters, or the treatment of fractures.

Fluoroscopy is a modality that provides a continuous, real-time x-ray image on a monitor, functioning much like an x-ray movie. During the procedure, the x-ray beam passes through the body from an x-ray source (usually at the bottom) to a receptor (at the top). Computed Tomography (CT) scans use x-rays to create cross-sectional pictures of the body. Magnetic Resonance Imaging (MRI) uses strong magnetic fields and radio waves (radiofrequency energy). The MRI signal comes primarily from protons in fat and water molecules, making the results dependent on the water content in the patient's body; it is particularly used for joint imaging.

Mammography is a specialized x-ray of the breast used to detect tumors or cancer, typically utilizing between $70$ and $75\,kVp$. Traditional mammography uses film, while digital mammography is currently the most common technique. Nuclear Medicine involves the injection, inhalation, or ingestion of radioactive tracers (radiopharmaceuticals). A common tracer is $tc99m$, which is radioactive and emits gamma radiation for approximately $6\,hours$. These emissions are captured by a gamma camera. Positron Emission Tomography (PET) scans use tracers like $f18$ (fluorodeoxyglucose), which has a half-life of $110\,minutes$, to look for diseases by showing how organs and tissues are working. PET/CT machines combine the structural detail of CT with the functional data of the gamma camera.

Ultrasound uses high-frequency sound waves (ranging from $20\,Hz$ to $20,000\,Hz$) to create images of internal structures. Unlike CT or x-ray, ultrasound does not use ionizing radiation. Radiation Therapy, occurring within the therapeutic branch, uses intense energy beams to kill cancer cells. Sources like Cobalt $60$ or machines like the Linear Accelerator (LINAC) are used. Radiation therapy can be delivered as external beam therapy or internal beam therapy (using pellets).

Legal Framework and Practice of Radiologic Technology in the Philippines

The practice of radiologic technology is governed by specific laws and regulations to ensure public safety. In the Philippines, the Radiologic Technology Act of $1992$ (Republic Act No. $7431$) regulates the profession and created the Board of Radiologic Technology. This Act stipulates that the practice includes any professional service rendered by a radiologic technologist, requiring the application of the art and science of the field. Under Section $15$, no person may practice as a radiologic or x-ray technologist without a certificate of registration from the Board. Section $23$ requires all successful examinees to take a professional oath before beginning practice.

The Professional Regulation Commission (PRC) is the body mandated to enforce these laws. It was created by Presidential Decree (PD) No. $223$ on June $22, 1973$, and was eventually modernized by Republic Act No. $8981$ (The PRC Modernization Act of $2000$). Fees for the profession are regulated: the exam application costs $P350.00$, registration is $P250.00$, and replacement of a lost certificate is $P100.00$. Penal provisions under Section $26$ state that practicing without a license, using someone else's certificate, or using a revoked license can result in a fine between $P10,000$ and $P40,000$, and/or imprisonment for $1$ to $6\,years$.

The Radiologic Technology Curriculum and Clinical Education

The educational path for a Bachelor of Science in Radiologic Technology (BSRT) is a four-year degree program. The curriculum is divided into several components. General Education (GE) courses account for $36\,units$. Core Courses comprise $15\,units$, including Human Anatomy and Physiology ($3\,units$), Medical Terminology ($3\,units$), Introduction to Research ($3\,units$), Research Writing ($3\,units$), and Statistics ($3\,units$). Other requirements include the Life and Works of Rizal ($3\,units$), Physical Education ($8\,units$), and NSTP ($6\,units$).

Professional Courses total $113\,units$. Courses assigned $2\,units$ include Imaging Equipment and Maintenance, Radiobiology, Radiation Protection, and Mammography. Courses assigned $3\,units$ cover a wide range of topics such as Patient Care and Management, Radiologic Pathology, CT, MRI, Ultrasound, and Nuclear Medicine. Specialized training in Radiographic Anatomy and Physiology is $4\,units$, while Radiographic Positioning and Radiologic Procedures is $8\,units$. The program culminates in a Clinical Education phase (internship) lasting $11\,months$ and accounting for $36\,units$. This internship provides the hands-on practical training necessary to operate equipment and manage clinical paperwork.

Professional Standards, Performance Indicators, and Ethical Practice

Radiologic technologists are held to high standards of professional practice. They must demonstrate the ability to apply scientific knowledge and technical skills, which includes performing procedures according to protocol, correctly positioning patients, producing high-quality images, and maintaining good housekeeping. Ethical standards include observing patient confidentiality (as dictated by the Patient’s Bill of Rights) and adhering to the professional Code of Ethics.

Radiation safety is a paramount performance indicator. Technologists must wear protective shields, such as lead aprons and goggles, collimate the area of exposure to reduce unnecessary radiation, and utilize the lowest possible exposure technique factors (the ALARA principle). They are also responsible for restricting unauthorized persons from exposure areas and ensuring the red warning light is active during exposures. Compassionate patient care involves giving clear instructions, providing privacy for changing into gowns, and transferring patients between wheelchairs or gurneys with minimal discomfort. Effective technologists also show leadership, engage in research, and advocate for lifelong learning by attending seminars and pursuing graduate studies.

Career Opportunities and Continuing Professional Development

Graduates of the BSRT program are expected to fulfill various professional roles. These include working as a Radiologic Technologist, Administrator, Educator, Researcher, or Entrepreneur. Article IV of the profession's governing rules emphasizes the responsibility to self and the importance of Continuing Professional Development (CPD). Technologists are expected to upgrade their standards of practice through CPE/CPD and take active roles in professional societies. They are also encouraged to share their knowledge with colleagues and other health professionals.

Specific ethical prohibitions include rendering professional services while under the influence of alcohol or drugs, avoiding conflicts of interest that could discredit the profession, and ensuring their names or certificates of registration are not used by others without written consent. Technologists are also entitled to just and fair compensation for their professional services.

Global Pioneers in Physics and Electricity

The discovery of x-rays was built upon centuries of research in electricity, vacuums, and image-recording materials. Significant global pioneers include:

• Evangelista Torricelli ($1643$): Invented the barometer and produced the first recognized vacuum.

• Otto Van Guericke ($1646$): Invented an air pump capable of removing air from a vessel.

• William Gilbert: Studied electricity and magnets; invented the primitive electroscope.

• Isaac Newton: Improved the static generator.

• Abbe Jean-Antoine Nollet: Improved the electroscope and created a vessel for discharging electricity in a vacuum, a forerunner to the x-ray tube.

• Michael Faraday ($1831$): Discovered electromagnetic induction.

• William Crookes, Johann Wilhelm Hittorf, and Phillip Lenard: Advanced the study of cathode rays.

• William Goodspeed ($1890$): Produced a radiograph prior to Roentgen but did not publish or pursue it.

• Johann Heinrich Schulze ($1727$): Produced the first photographic copy of written material.

• Richard Leach Maddox ($1871$): Produced a film with gelatin silver bromide emulsion.

• George Eastman ($1884$): Produced and patented roll-paper film.

Discovery of X-Rays: Wilhelm Conrad Roentgen

Wilhelm Conrad Roentgen was born on March $27, 1845$, in Lennep, Germany, as the only child of Friedrich Conrad Roentgen and Charlotte Constanze Frowein. He studied at the Polytechnic Institute in Zurich and was eventually appointed to the faculty of the University of Wurzburg. On November $8, 1895$, while director of the Physical Institute, he discovered x-rays. He had darkened his lab and enclosed a Crookes tube with black photographic paper, noticing that a screen coated with barium platinocyanide (referenced as barium cyanide in early contexts) began to glow—a phenomenon known as fluorescence.

Roentgen's immediate investigations involved interposing various materials like wood and aluminum between the source and a screen. His first medical x-ray image was published in early $1896$. In the United States, the first x-ray examination occurred in early February $1896$ at Dartmouth College on a patient named Eddie McCarthy from Hanover, New Hampshire. Roentgen received the first Nobel Prize in Physics in $1901$ for his discovery. He died on February $10, 1923$, in Munich at the age of $77$.

History and Pioneers of Radiologic Technology in the Philippines

In the Philippines, several key figures and groups shaped the profession. Norberto Palomo is known as the "Father of Radiologic Technology in the Philippines." He was the president of the Philippine Society of Medical Radiologic Technology (PhisMert) and, alongside Serafin Ocampo, Benjamin Hernandez, and Jayne Vallarino, set up the curriculum for the first x-ray technology education. This curriculum was based on models from Australia, England, Singapore, and Japan. The first school to offer x-ray technology was The Family Clinic and Hospital, which received its permit on September $9, 1969$.

Other notable pioneers include:

• Gilberto Palomique: First president of the Philippine Association of Radiologic Technology (PART).

• Almario Lutap: First president of the Philippine Institute of Radiologic Technology (PIRT).

• Dr. Macaria Roque: The first Filipina radiologist.

• Felipe Somera: The first Filipino x-ray technologist, a nurse at PGH.

• The Magnificent 7: The first seven radiologists in the Philippines: Dr. Paterno Chikiamco, Dr. Ramon Paterno, Dr. Paulino J. Garcia, Dr. Daniel Ledesma, Sr., Dr. Carlos Marquez, Dr. Hilario Zialcita, and Dr. Carlos Vergel de Dios.

Regulation, Professional Organizations, and the Regulatory Board

The professionalization of radiologic technology in the Philippines saw three main societies emerge in $1973$: PhisMert, PSRT, and PIRT. Eventually, the Philippine Association of Radiologic Technologists, Inc. (PART) became the integrated association. PART was founded in May $1954$ and was accredited by the PRC in September $1992$. Following the approval of the Radiologic Technology Act in $1992$ by President Corazon Aquino, the Board of Radiologic Technology was established on February $27, 1992$.

The first Board members were Fortunato C. Gabon Jr. (Chairman), Jose T. Gaffud, Editha C. Mora, Dexter R. Rodelas, and Dr. Eulinia M. Valdezco. To be a board member, one must be a Filipino citizen, of good moral character, at least $30\,years$ of age, and not a member of a faculty. On December $27, 1993$, the board conducted the first computerized licensure examination, with results released on April $9, 1994$. Earlier recommendations by the Secretary of Health, Clemente S. Gatmaitan, to President Ferdinand Marcos in the early $1970s$ had paved the way for creating a regulatory agency to protect citizens from radiation hazards.