What is deviation index in radiography?

The deviation index quantifies the difference between the actual EI and the Target EI, and this feedback allows the radiographer to track and adjust his or her exposures. When the actual EI is equal to the Target EI, the DI will equal 0.

What does the exposure index number indicate?

The exposure index (EI) in digital radiography has been used to indicate the relative speed and sensitivity of the digital receptor to incident X-rays and, ideally, to provide feedback to the technologist regarding the proper radiographic techniques for a specific exam that achieves an optimal image in terms of …

How do radiographers select exposure factors?

The primary exposure technique factors the radiographer selects on the control panel are milliamperage, time of exposure, and kilovoltage peak (kVp). Depending on the type of control panel, milliamperage and exposure time may be selected separately or combined as one factor, milliamperage/second (mAs).

Are the target exposure index and deviation index used efficiently?

Conclusion: The study shows that the EIT and DI are not used efficiently, regardless of equipment vendor or department characteristics.

What is maximum ISO sensitivity?

The ISO rating, which ranges in value from 25 to 6400 (or beyond), indicates the specific light sensitivity. Conversely, a higher number indicates a higher sensitivity to light, thereby allowing that film or image sensor to work better in low light conditions.

What does kVp measure?

Kilovoltage peak (kVp) is the peak potential applied to the x-ray tube, which accelerates electrons from the cathode to the anode in radiography or computed tomography. Tube voltage, in turn, determines the quantity and quality of the photons generated.

What is brightness in radiography?

Brightness – intensity of light representing individual pixels in an image. Contrast – differences in brightness between light and dark areas of image. Subject contrast – is the ratio of the radiation intensities in different parts of an image due to the quality of the subject being imaged.

What is quantum noise in radiography?

Quantum noise, also called quantum mottle, is the main and the most significant source of noise in plain radiography. It is a random process due to fluctuations in the number of photons reaching the detector from point to point.

What is a deviation index (DI)?

Deviation Index (DI) provides feedback to the operator with a value that is equal to 0 when the appropriate exposure to the detector is achieved, a negative number when underexposure has occurred, and a positive number when overexposure has occurred.

What are the different types of radiography exposure indicators?

The names include S-number, REG, IgM, ExI and Exposure Index. Carestream’s computed radiography (CR) and digital radiography (DR) systems both reference their exposure indicator as the exposure index or EI. After an exposure is made, the resulting image appears on the monitor and displays a number in the Exposure Index field.

What is the target exposure index for chest radiograph?

Target exposure index (EIT) for adult chest radiograph is currently set at 300 for DXG CR system (Agfa). B, Red regions of interest (ROIs) over lungs were selected by user and EI increased to 375 with DI of 1.0.

Is there a standard for exposure index for digital X-ray imaging systems?

Fortunately, there is a standard for exposure index for digital X-ray imaging systems. Developed concurrently by the International Electrotechnical Commission (IEC) and the American Association of Physicists in Medicine (AAPM), in cooperation with digital radiography system manufacturers, the index has been implemented as an international standard.