PIAAA Features

Main features
Test objects
How to use it
Hardware requirements

Main Features

The purpose of PIAAA is to provide a flexible, efficient tool for the automatic acquisition and analysis of phantom images during routine Quality Control (QC) procedures in diagnostic radiology. Two kinds of problem are often encountered in practice by people coping with daily/weekly assessment of image quality of radiological imaging systems.

The first problem concerns the repeatability of subjective evaluations of phantom details (e.g.: number of visible details of any kind). It often happens that the result varies from observer to observer thus leaving the QC manager in front of the following question:

Do I consider the observed variation of the number of visible details the consequence of an inter-observer variation or of a changed performance of the radiological system?

Neither solution is satisfactory and in practice the consequent strategy of the QC manager is to ignore variations of ±1 details thus significantly reducing the sensitivity of the phantom in detecting malfunctions.

The second problem concerns the cost associated to the frequent evaluation of phantom images. For example, in the case of mammographic phantoms that are often complex and rich in details, the radiologist or the QC technician spend a minimum of 15 minutes to read the image and record the data. If this exercise is performed daily, 60-70 radiologist (or technician) hours are spent every year for an estimated cost of not less than 3000 euros.

PIAAA puts an end to these problems as it can be verified by looking at the following scenario. The radiologist (or the QC technician) takes a film of the phantom. Puts the film on the plate of the scanner piloted by PIAAA. A click of the mouse makes PIAAA acquire, analyse and find all the information contained in the phantom image.

The radiologist has spared 15 minutes of his/her precious time and the QC manager can make his evaluations without any bias introduced by subjective assessment of the image. Moreover, much more information is available now than with the manual method: several parameters can be assessed like MTF, contrasts, noise thanks to the exploitation of the whole information contained in the digitised image of the phantom.

The information can be easily stored in appropriate format or sent to a QC supervision centre through the Internet. An automatic feature of PIAAA assures the direct transmission of all the data to a QUACKS an expert system centre for immediate interpretation thus allowing remedial actions to be taken in due time.

PIAAA can be also used by skilled QC managers and medical physicists to make their own evaluations and analysis of phantom images by means of the numerous tools and filters available in the software.

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Test objects

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How to use it

PIAAA is very simple to use. You only need to put the Phantom Mask (a plastic or cardboard frame supplied with the software which includes a calibration strip) on the plate of the scanner. Then you put the phantom film (18x24 cm) in the appropriate frame inside the mask. You even do not have to bother about the orientation of the film: PIAAA recognises it!
Then you make a click on the appropriate phantom button, and that is all! PIAAA takes a few minutes to perform its task and show you the final results. Another click is enough to send the data to your supervision centre.

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Hardware requirements

The maximum optical density that can be accurately evaluated depends on the scanner specifications. It should be not less than 3.0 OD in order to appropriately estimate the average gradient of a sensitometric strip. The resolution limit that can be approached is dependent on the optical resolution of the scanner. Typically, a scanner with an optical resolution of 1200 dpi has a resolution limit of about 10 lp/mm.

Scanner requirements

Scanners currently tested are:

PC System Requirements

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