What are the basic principles of radiography?

It is based on the principle that radiation is absorbed and scattered as it passes through an object. If there are variations in thickness or density (e.g. due to defects) in an object, more or less radiation passes through and affects the film exposure. Flaws show up on the film, usually as dark areas.

What is the method of radiography?

During a radiographic procedure, an x-ray beam is passed through the body. A portion of the x-rays are absorbed or scattered by the internal structure and the remaining x-ray pattern is transmitted to a detector so that an image may be recorded for later evaluation.

What is the principle of generation of X-ray?

X-rays are commonly produced in X-ray tubes by accelerating electrons through a potential difference (a voltage drop) and directing them onto a target material (i.e. tungsten). The incoming electrons release X-rays as they slowdown in the target (braking radiation or bremsstrahlung).

What is the basic principle of computed tomography?

CT is based on the fundamental principle that the density of the tissue passed by the x-ray beam can be measured from the calculation of the attenuation coefficient.

What are the basic principles of image production during CT examination?

In the particular case of the CT, the emitter of x-rays rotates around the patient and the detector, placed in diametrically opposite side, picks up the image of a body section (beam and detector move in synchrony). Unlike x-ray radiography, the detectors of the CT scanner do not produce an image.

What is the principle work of CT scan including of diagnostics?

The term “computed tomography”, or CT, refers to a computerized x-ray imaging procedure in which a narrow beam of x-rays is aimed at a patient and quickly rotated around the body, producing signals that are processed by the machine’s computer to generate cross-sectional images—or “slices”—of the body.

What is the principles of safety in radiation therapy?

The aim of radiation protection is to reliably prevent the deterministic effects of radiation and to reduce the risk of stochastic effects to a reasonably achievable level. The dose limits are set so that deterministic effects are ruled out.

What are the methods of radiation protection?

The three basic methods used to reduce the external radiation hazard are time, distance, and shielding. Good radiation protection practices require optimization of these fundamental techniques.

What is MRI principle?

MRIs employ powerful magnets which produce a strong magnetic field that forces protons in the body to align with that field. When a radiofrequency current is then pulsed through the patient, the protons are stimulated, and spin out of equilibrium, straining against the pull of the magnetic field.

What is matrix in CT?

Matrix: Two dimensional grid of pixels, used to compose images on a display monitor. The matrix determines the number of rows and columns. Pixel: Two dimensional picture element that makes up the matrix. Each pixel represents a CT number and is the building block of the matrix and image.

What is the basic techniques involved in computed tomography?

During a CT scan, the patient lies on a bed that slowly moves through the gantry while the x-ray tube rotates around the patient, shooting narrow beams of x-rays through the body. Instead of film, CT scanners use special digital x-ray detectors, which are located directly opposite the x-ray source.

What are the principles of radiography in non destructive examination?

The principles of radiography in Non-Destructive Examination. X-rays and gamma radiation have wavelengths shorter than 100 nanometres (nm). Energy, at these wavelengths, will penetrate solid material. The shorter the wavelength, the greater the penetration.

How are X-rays made into radiographic images?

This means that the X-rays, which have passed through the body, must be made to strike an image receptor that will produce a visible image, for example an imaging plate. The principal interactions involved in the basic requirements for the formation of a radiographic image are shown in Figure 1.2.

What is a radiographic examination (radiographic testing)?

Radiographic Testing or Radiographic Examination is a non-destructive testing (NDT) method for examining the internal structure of any component to identify its integrity.

What are the steps in the radiographic test procedure?

Radiographic Testing Procedure Step 1- Surface Preparation: . Surface irregularities must be removed so that they can not mask or confuse the image as… Step 2- Selecting the right radiation source and radiographic film: . Depending on radiographic sensitivity and material… Step 3- Selection of