RT

Due to the imperfection of measurements, several types of errors are induced in the process and the results of a spatial analysis are further degraded.

_ are very important for digital image production. However, they can be the source of bothersome digital radiographic image artifacts if improperly understood and manipulated.

have the ability to evaluate the original image data through histogram analysis.

is a plot of the frequency of appearance of a given object characteristic.

_ chest image histograms and averaging the value of each frequency interval, a representative histogram is produced for each image receptor. The histogram can be regularly updated with newer images.

If the xray exposure field is not properly collimated, sized, and positioned, exposure field recognition errors may occur. These can lead to histogram analysis errors because signal outside the exposure field is included in the histogram.

_ of the exposure field on the IP is important in the same way and for the same reason as collimation. When an image field is not oriented with the size and dimensions of the IP, image artifacts can appear.

that comes from environmental sources including the earth's crust, the atmosphere, cosmic rays, and radioisotopes.

a gas produced by radium decay within rock.

define and diagnose medical conditions are the greatest manmade source of ionizing radiation exposure to the general population.

such as those delivered to patients during diagnostic procedures may pose a risk, albeit small, of inducing cancer years to decades following the examination.

Two major factors affect the amount and energy of scatter radiation exiting the patient.

depends on the thickness of the part and the x-ray beam field size. Increasing the _ results in increased scatter production.

however, higher kVp increases the percentage of Compton interactions and the energy of scatter radiation exiting the patient.

results in increased scatter radiation reaching the IR.

It is the responsibility of the radiographer to limit the xray beam field size to the anatomic area of interest.

Beam restriction serves two purposes

is cone shaped and projects a round field onto the patient and IR.

Because collimation decreases the xray beam field size, less scatter radiation is produced within the patient, and hence, less scatter radiation reaches the IR.

Increasing the collimation decreases the volume of tissue irradiated, the amount of scatter radiation produced, the number of photons that strike the patient, and the number of xray photons that reach the IR to produce the latent image.

Types of beam-restricting devices

The simplest type of beam-restricting device, a flat piece of lead that contains a hole.

are shaped differently but have many similar attributes.

The most sophisticated, useful, and accepted beam-restricting device.

are devices placed between the patient and the IR to absorb scatter radiation.

consists of two or more computers that are linked in order to share resources, exchange files, or allow electronic communications.

is a network that is confined to a relatively small area, such as a school or building.

are broadly categorized as servers or workstations.

are generally not used by humans directly, but rather run continuously to provide services to other computers.

are computers that typically have a human user interacting with them.

connect networks in larger geographic areas, such as a country or the world.

is a computer system that can manage all the information related to healthcare providers.

A type of medical practice management software that handles all tasks necessary to run a medical practice.

is a computer-based system designed for collecting, storing, and processing healthcare information.

is a networked software system for managing medical imagery and associated data.

is a healthcare technology for storing, retrieving, and managing medical images.

is the creation of a representation of the visual characteristics of an object.

is the first point of data entry into a PACS and can affect clinical operations.

The first step in image formation that involves collecting raw imaging data.

are the values of all measured detector signals during a scan.

The process of converting raw data into a visual representation.

An image that exists on film after exposure but before processing.

changes the latent image into a manifest image.

The image that exists on film after exposure and processing.

explains how latent image formation occurs at the molecular level.

An index of detector exposure reflective of noise content and signal-to-noise ratio in the image.

reflects the radiation exposure incident on a detector after each exposure.

results in an appropriate noise level in the image.