Radiation Technique, Radiation Protection, Quality Control, and Orthopedic Radiography

Flashcards based on lecture notes covering radiographic technical factors, radiation protection, quality control in digital imaging, and orthopedic implant procedures.

Radiographic Technique

The combination of factors used to expose an anatomical part to produce a high-quality radiograph.

kVp (Kilovolt Peak)

The primary control of X-ray beam quality and beam penetrability, serving as the most important influence on subject contrast.

Current (mA)

The amount of electrical current passing through the X-ray tube, which determines the number of X-rays produced.

Exposure time (s)

The duration of X-ray exposure, usually kept as short as possible to minimize motion blur and patient dose.

SID (Source to Image Distance)

The distance from the X-ray source to the image receptor that affects beam divergence and intensity.

Exposure Technique Charts

Charts used to provide a means for determining the specific technical factors required to produce desired optical density, contrast, detail, and distortion.

Optical Density (OD)

The degree of blackening of a radiograph or opaqueness of the film, where clear areas represent low OD and black areas represent high OD.

Radiographic Contrast

The difference in optical density between adjacent anatomical structures, or the variation in OD on a radiograph to make anatomy more visible.

Image Detail

The sharpness of appearance of small structures on the radiograph, evaluated by recorded detail and visibility of detail.

Spatial Resolution

The ability to demonstrate small objects or details that are close together as separate structures.

Distortion

Misrepresentation of the size and shape of an object on a radiograph.

Patient Factors

Characteristics including anatomical thickness, body composition, and pathology that influence the required radiographic technique.

Sthenic Body Habitus

Average, strong, active patient body habitus upon which standard radiographic technique charts are based.

Hyposthenic Body Habitus

A body habitus characterized by thin but healthy-appearing patients.

Hypersthenic Body Habitus

A body habitus characterized by a big frame, usually overweight patients.

Asthenic Body Habitus

A body habitus characterized by small, frail, sometimes emaciated, and often elderly patients.

Fixed-kVp Radiographic Technique Chart

An exposure selection method developed by Arthur Fuchs that produces radiographs with a longer scale of contrast.

Variable kVp Technique

Radiographic technique where kVp changes while mAs remains constant.

Automatic Exposure Control (AEC)

A system that maintains appropriate exposure by terminating exposure when sufficient radiation reaches the receptor, compensating for patient thickness and anatomical variations.

Calipers

A tool used by radiologic technologists to measure anatomical thickness along the central ray.

Resolution

The ability to distinguish or visualize small details or structures of similar subject contrast as separate entities.

Geometric Factors

Factors affecting the size and shape of the recorded image, including SID, OID, focal spot size, and alignment.

Small Focal Spot

Focal spot size option that provides better spatial resolution.

Large Focal Spot

Focal spot size option that offers greater heat capacity and permits higher X-ray production.

Magnification

A condition in which the images on a radiograph are larger than the object they represent, occurring when OID is larger.

Compression

Procedure used to reduce patient thickness, increase penetration, and improve image quality.

Collimation

The restriction of the X-ray beam to reduce unnecessary radiation exposure and scatter radiation.

Anode Heel Effect

Phenomenon where X-ray beam intensity is greater on the cathode side and lower on the anode side.

Thoreaus Filter

A compound filter combining Tin, Copper, and Aluminum to absorb radiation at complementary abilities.

Wedge Filter

A compensating filter used for exposures of the foot, femur, and thoracic spine.

Bilateral Wedge Filter

A compensating filter used for chest radiography.

Bowtie Filter

A compensating filter used specifically in CT imaging.

Conic Filter

A compensating filter used in fluoroscopy.

Step Wedge Filter

A compensating filter used in angiography of extremities.

Ferric Filter

A compensating filter used in scapular Y and Danellius-Miller projections.

Boomerang Filter

A compensating filter used for shoulder examinations.

Filtration

The removal of low-energy photons from the X-ray beam to increase average beam energy/quality and reduce patient dose by up to 50% ESE.

Inherent Filter

Filter found inside the X-ray tube housing, measuring $0.5$ mm Al equivalent.

Added Filter

Filter placed after the X-ray tube, consisting of $2.0$ mm Al or a $1.0$ mm Al mirror.

Compensating Filter

A filter used to compensate for large differences in tissue thickness to produce uniform optical densities.

Grids

Devices invented by Gustav Bucky (1913) used to absorb scatter radiation before it reaches the image receptor to increase contrast.

Glitterblende

The first checkerboard grid invented by Gustav Bucky in 1913.

Primary Radiation

Radiation that travels directly from the X-ray tube toward the image receptor.

Scatter Radiation

Radiation that has been deflected from its original path after interacting with matter, resulting in decreased image contrast.

15% kVp Rule

A rule stating that a 15% increase in kVp doubles receptor exposure (+100% density), and a 15% decrease halves receptor exposure (-50% density).

Film Speed

Refers to the sensitivity of radiographic film to exposure.

Screen Speed

A relative number describing how efficiently X-rays are converted into light by intensifying screens.

Beam Hardening

An increase in average X-ray beam energy resulting from increased filtration.

Radiation Protection (IAEA Definition)

The protection of people from harmful effects of exposure to ionizing radiation and the means of achieving this.

Non-ionizing Radiation

Electromagnetic radiation not capable of removing electrons from orbital shells, such as radiowaves, microwaves, infrared, and visible light.

Ionizing Radiation

Radiation capable of removing electrons from orbital shells, such as UV, X-rays, gamma rays, alpha, beta, and neutrons.

Radiowaves

Electromagnetic radiation with the longest wavelengths and lowest frequencies in the electromagnetic spectrum.

Microwave Radiation

Electromagnetic radiation used for communication, broadcasting, heating, and medical microwave ablation therapy.

Infrared Radiation

Electromagnetic radiation categorized into near, mid, and far IR, used in thermography and therapeutic applications.

Visible Light

The only type of electromagnetic spectrum that responds to the human eye.

Alpha Particles

Composite particles consisting of 2 protons and 2 neutrons tightly bound together emitted during alpha decay.

Beta Particles

High-energy, high-speed electrons or positrons ejected from the nucleus during beta decay.

Neutron Beams

Beams generated by released neutrons during nuclear fission of heavy nuclei like uranium.

Proton Beams

Beams generated by a PIG ion source located at a cyclotron center via plasma discharge ionization.

X-rays

High-energy electromagnetic waves capable of passing through most objects, including the human body.

Gamma Rays

Electromagnetic waves with the smallest wavelength and highest energy, produced by energetic cosmic phenomena or nuclear activity.

Activity (Radiation)

The phenomenon of spontaneous disintegration of unstable nuclei to form more energetically stable atomic nuclei.

Absorbed Dose

The amount of radiation energy deposited in a mass of material or tissue.

Exposure (Radiation)

A measure of ionization in air caused specifically by X-rays or gamma rays.

Effective Dose

A calculated quantity summing different exposures into a single number reflecting overall biological risk.

Deterministic Effects

Radiation health effects that have a threshold dose below which the effect does not occur, with severity increasing as dose increases.

Stochastic Effects

Radiation health effects assumed to have no threshold dose, where dose increases probability of occurrence but not severity.

Temporary Male Sterility Threshold

Direct radiation dose of $0.15$ Gy to the testes.

Permanent Male Sterility Threshold

Direct radiation dose of $15$ Gy to the testes, equivalent to 150 chest X-rays.

Female Sterility Threshold

Direct radiation dose of $4$ Gy (or 40 chest X-rays), causing 30% sterility in young women and 100% in women over 40.

Cataractogenesis Threshold

A dose threshold of $5$ Gy for cataract development, or $0.5$ Gy for detectable lens opacities.

Erythema Threshold

Skin reddening occurring at radiation doses of $3-6$ Gy, or 30-60 chest X-rays.

Law of Bergonie & Tribondeau

Principle stating radiosensitivity is higher in stem cells, younger tissues, highly metabolic tissues, and rapidly proliferating cells.

ALARA

As Low As Reasonably Achievable; avoiding unnecessary radiation exposure using time, distance, and shielding.

Justification of Practices

Principle stating no practice involving radiation exposure should be adopted unless it produces sufficient benefit to offset radiation detriment.

Optimization of Protection

Principle stating radiation doses should be kept ALARA, taking economic and social factors into account.

Limitation of Doses

Principle stating individual dose equivalents shall not exceed recommended limits set by the ICRP.

Histogram

A graph produced in digital imaging by computing the frequency of pixel values to define attenuated exposure versus non-exposure areas.

Pixel

Picture element; the basic 2-dimensional component of a digital image.

Voxel

Volume element; a 3-dimensional digital image element that includes depth, such as in CT and MRI images.

Matrix

A series of pixels arranged in rows and columns that forms the displayed digital image.

Bit

Exponent of base 2 determining the available gray scale shades in a digital image.

Window Width

Post-processing control determining the gray scale range; larger width increases grays and lowers image contrast.

Window Level

Post-processing control determining image density or brightness; higher numbers yield a brighter image.

Veil Glare

Eye glare caused by bright unexposed borders around collimation edges oversensitizing rhodopsin in the eye.

Shuttering

A digital viewing technique used to blacken out white unexposed collimation borders to eliminate veil glare.

Image Stitching

Computer process joining multiple contiguous digital images into a single view for anatomy too large for one cassette.

PACS

Picture Archiving and Communication System; a network used in hospitals for digital storage and easy multi-device access of patient images.

DIMS

Digital Image Management System; the older designation for PACS.

Orthopedic Implants

Metallic plates, screws, or tissues grafted or inserted into a patient's body to assist, localize, or stabilize bone.

Prosthesis

A total or partial artificial replacement for a body joint or structure made of materials like cobalt chrome, polyethylene, plastic, or ceramic.

Intramedullary Nail (IM Nail)

A load-sharing metal rod inserted into the medullary cavity across a fracture providing strong mechanical fixation.

Masquelet Technique

A two-stage surgical technique for bone loss using a cement spacer first to induce a membrane, followed by reconstruction plating.

Luque Sublaminar Wiring

A posterior rigid fixation technique for spinal correction utilizing rods connected via sublaminar wires.

MIPO

Minimally Invasive Plate Osteosynthesis; inserting plates through small soft tissue incisions with percutaneous screws.

Antibiotic Beads

Implanted PMMA beads that release targeted therapeutic medicine inside bone to treat septic arthritis and osteomyelitis.

Dynamic Hip Screw (DHS)

A femoral head-sparing orthopedic device (pin and plate) used to treat femoral neck fractures.

Femoral Neck Screw (FNS)

Fixation solution designed for improved angular and rotational stability in fused femoral neck fractures.

ILIZAROV External Fixator

A stabilizing external frame used as a limb-sparing technique for complex or infected open bone fractures.

Judet View Radiography

Radiographic examination for evaluating acetabular fractures using Obturator (45° away) and Alar (45° toward) views.