Radiology General Review PDF

Imaging Methods Radiography Roentgenoscopy Scintigraphy Computed tomography (CT) Magnetic Resonance Imaging(MR) Ultrasonography Thermography The main imaging methods used today are; x-ray Computed Tomography Magnetic Resonance Imaging Ultrasonography Radionucl...

Imaging Methods Radiography Roentgenoscopy Scintigraphy Computed tomography (CT) Magnetic Resonance Imaging(MR) Ultrasonography Thermography The main imaging methods used today are; x-ray Computed Tomography Magnetic Resonance Imaging Ultrasonography Radionuclide Imaging  These methods are based on different physical principles. Transmission Reflection Emission (Reflection) Emission In this imaging, the energy source is in the body. To create the image, the energy released from the body must be received and processed. In order to create the energy that gives signals in the body, some radionuclide materials need to be delivered to the tissues and organs by different means, as in radionuclide imaging. As with magnetic resonance imaging (MRI), radiofrequency tissues need to be stimulated  Transmission (Passing) The energy used in imaging methods based on this principle must pass through the organism and reach the receiver on the opposite side. Here the energy source and receiver are different. This principle is valid in X-ray and computed tomography methods. Reflection In this principle; energy source and receiver are on the same side. After the produced energy is sent to the organism, the reflected energy is collected and an image is formed. Ultrasonography works on this principle. Indications of Radiography Identification of a specific formation Evaluation of the spread of a disease Follow-up of a progressive lesion or healing Evaluation of a pathological formation Ultrasonography In this diagnostic technique, an image is formed by transmitting the sound waves from the probe on the ultrasonography device to the patient and by taking the sound waves reflected from the patient from the probe again. Evaluation of soft tissues, abdominal structures, as well as the heart Structures examined by ultrasonography; Evaluate size, shape, echogenicity (bright spots and dark spots) and position. Internal structures can be evaluated. Images during ultrasonography are moving, ultrasonographic waves cannot penetrate air or bone. Experience and anatomy knowledge of the physician is very important in ultrasonographic examination. Computed Tomography (CT) X-rays are used to obtain images. Transmission has a physical feature. Using multiple detectors, images of the living body in the form of sections are obtained. Scan times are very short. Examined structures; size, shape, density, location, and superposition is not formed in this diagnostic technique. Computer manipulation of images is required. Magnetic Resonance Imaging (MRI) Only radiofrequency waves are used, no ionizing radiation. When the hydrogen atoms in the living body are stimulated with radiofrequency waves, an image is formed. Cross-sectional images are obtained. (as in BT) It is the most ideal diagnostic method for imaging soft tissues. It is especially best for the central nervous system.  Diagnostic radiology consists of four main methods: X-ray, Computed tomography (CT), Magnetic resonance imaging (MRI), and Ultrasonography (US). Some of these diagnostic and therapeutic devices involve ionizing radiation. Types of Energy Used in Radiology Two main categories: 1. Electromagnetic radiations, X-rays, X-ray imaging, Computed tomography (CT), Gamma rays, Nuclear medicine (NM), Radio waves, Magnetic Resonance Imaging (MRI) 2. Ultrasound energy, Ultrasonography (US) The basic radiology unit is divided into two categories: diagnostic and interventional. 1. Diagnostic Radiology: This is the branch of radiology focused on using various imaging techniques to diagnose diseases and conditions. X-rays, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasonography (US)  X-ray Machines: X-ray machines are imaging devices that enable the production of X-rays in the desired duration, quality, and quantity. X-rays are a form of ionizing radiation. X-rays are used in radiology is their ability to penetrate tissues.  The human body is composed of tissues with varying atomic weights, thicknesses, and densities. As a result, when X-rays pass through these tissues, they reflect onto the X-ray film at different rates. This reflection produces an image with shades of gray ranging from black to white. The method of obtaining an image by passing X-rays through the body part to be examined and projecting them onto film is called radiography.  Computed Tomography (CT): Computed tomography (CT) is a cross-sectional imaging method theorized by Cormack in 1963. CT, which is based on the principles of the X-ray machine, is a diagnostic method that uses X-rays to create cross-sectional images of the examined area of the body. In computed tomography (CT) a three-dimensional image. (3D)  CT has a wide range of applications in thoracic and abdominal imaging. If there are masses in these areas, their boundaries and spread to surrounding tissues can be visualized.  With MRI, organs, soft tissues, and bones can be imaged. MRI does not use ionizing radiation (there are no X-rays involved). A large tube-shaped magnet creates a magnetic field around the patient.  Ultrasonography (US) - Doppler Ultrasound (Doppler US): Ultrasonography is the process of converting sound energy into images using high- frequency sound waves. In ultrasonography, the reflection of ultrasound waves is utilized to create visual representations of internal body structures.  One significant advantage of ultrasonography is that, because it does not involve ionizing radiation, it can be safely used in infants and pregnant women. Since ultrasonography is known to have no harmful effects  2. Interventional Radiology Interventional radiology includes diagnostic and therapeutic procedures that are performed by entering the body through pathways as small as a needle puncture, without the need for surgical incisions. Diagnostic procedures include: biopsies, drainage, angiography, In these units, the imaging procedures involve the use of harmful rays known as ionizing radiation, and devices that use X-rays are commonly utilized.  Radiation Radiation is energy emitted from a source in the form of electromagnetic waves or particles. lasers, the sun, radar systems, television transmitters, X-ray machines, and radioactive materials.  IONIZING RADIATION Any electromagnetic or particulate radiation capable of producing ion pairs by interaction with matter. Scope limited to X and gamma rays, alpha particles, beta particles (electrons), neutrons, and charged nuclei. Important biologically since media can be altered (e.g., ionized atom in DNA molecule may be altered, thereby causing cell death, or mutation).  What are X-Rays? X-rays are high-energy electromagnetic waves. They have much shorter wavelengths and higher energy compared to visible light. X-rays are ionizing radiation, meaning they can remove electrons from atoms. X-Rays in the Electromagnetic Spectrum X-rays lie between ultraviolet light and gamma rays in the electromagnetic spectrum. Shorter wavelengths and higher energy than visible light. X-rays are classified as: 1. Soft X-rays (lower energy, 0.12-12 keV) 2. Hard X-rays (higher energy, 12 keV and above)  Radiation Radiation can be thought of as the transmission of energy through space. Two major forms of radiation: – Electromagnetic (EM) radiation – Particulate radiation Both forms can interact with matter, and transfer their energy to the matter. Where Do We Use X-ray In Diagnostic Radiology? ROENTGENOGRAM COMPUTED TOMOGRAPHY (CT) Applications of X-Rays Medical Imaging X-rays are widely used in diagnostic imaging to visualize bones and soft tissues. Common procedures include X-rays, mammograms, and CT scans. Used to diagnose bone fractures, lung infections, tumors, and dental problems. Low-energy X-rays (soft X-rays) are used for imaging soft tissues like the lungs and abdomen.  Radiation Therapy High-energy X-rays (hard X-rays) are used in cancer treatment. They target and destroy cancer cells while minimizing damage to surrounding tissues. X-ray therapy is commonly used in radiation oncology to treat tumors and cancers. Modern radiation therapy can precisely target tumors using computed tomography (CT) scans for guidance. Security and Forensics X-rays are used in security screenings, such as at airports, to scan baggage and detect hidden objects. X-ray machines are used to detect contraband, weapons, and explosives in luggage. Computed Tomography (CT) Scans CT scans combine X-rays and computer technology to create detailed cross- sectional images. Used to diagnose complex conditions like internal bleeding, tumors, and organ damage. CT provides 3D images of soft tissues, bones, and blood vessels, making it essential in trauma cases. CT scans are commonly used in cancer diagnosis and monitoring.  Properties of X-ray Are electromagnetic radiations composed of small pockets of energy called «photons». Travel et speed of light Travel in straight lines Higly penetrating Invisible Blacken radiographic films Produce scatter  TRANSMISSION: is the amount of X-ray passing through the patient ABSORPTION: is the amount of X-ray hold or absorbed by the patient ATTENUATION: during the transmission of X-ray through the patient some is hold/absorbed by the patient so the amount of X-ray decreases The Biological Effects of Ionizing Radiation The biological effects of ionizing radiation on irradiated tissue depend on factors such as the total dose received, the dose rate, the amount of the body exposed to radiation, radiosensitivity, and the type of radiation emitted. These factors can lead to stochastic (random) and deterministic effects. 1. Deterministic Effect: high doses of radiation. 2. Stochastic Effects: long-term exposure to very low doses PROTECTION FROM EXTERNAL RADIATION Armoring Distance Time distance Radyoaktive source Dose rate Dose rate Concrete Distance from radioactive time spent thickness source TIME The less time spent near the radioactive source, the less exposure. Dose = (Dose rate) x (Time) DISTANCE By moving away from the radiation source, the amount of exposure can be reduced. Radiation loses its intensity as it moves away from the radioactive source, inversely proportional to the square of the distance. 3m 1m 9 mSv/h 1 mSv/h Dr= D0 (r0/r)2 ARMOURING A suitable barrier is placed between the radiation source and the person. Materials made of high-density materials provide particularly effective protection against X and gamma rays.  Fundamental to radiation protection: Time, Distance, Shielding. ALARP & ALARA ALARP is an acronym for an important principle in exposure to radiation and other occupational health risks and in the UK stands for "As Low As Reasonably Practicable". The aim is to minimize the risk of radioactive exposure or other hazard while keeping in mind that some exposure may be acceptable in order to further the task at hand.  The ALARA principle is based on three main strategies: 1. Time: Reducing the amount of time spent near radiation sources to decrease exposure. 2. Distance: Increasing distance from the radiation source to lower exposure levels. 3. Shielding: Using protective materials (such as lead or concrete) to limit exposure by blocking radiation. Personal Radiation Dosimeters The radiation dosimeter is an important personal dose measuring instrument. Personal Protectıve Equıpment Lead Apron Glove Thyroid Shield Glasses Lead Screen Gonad Protector Methods Of Radiation Dose Reduction Calibration and quality tests of radiation emitting devices should be done periodically. A correctly calibrated device prevents overdose of the worker and patient. Since there are lead plates in the lead apron that cannot be folded, it should be kept on a proper hanger so that it cannot be folded. Lead aprons should be checked periodically every 6 months. In the control, the film of the large surface of the lead apron is taken.