Advantages of digital radiography for clinical diagnosis | Disadvantages of digital radiography
This page covers advantages and disadvantages of digital radiography for clinical diagnosis. It mentions benefits or advantages of digital radiography and drawbacks or disadvantages of digital radiography.
Introduction: X-rays are absorbed by human body in relation to specific density and atomic number of tissues in the body. These absoption differences by various parts of our body are recorded on image receptor or detector. The radiography imaging system uses x-rays, gamma rays or similar non-ionizing radiations to view internal parts human body. Traditional radiography was using x-ray films to store images.
What is digital radiography?
Now-a-days there are two popular types of radiography systems viz. Computed radiography (CR) and digital radiography (DR). Both are digital imaging techniques in which acquired images can be viewed and manipulated on computer. Computed radiography uses CR cassette and imaging plate to record the image. Reader is required to read the image from cassette or plate with the help of laser. Cassette less digital radiography system can be categorized into direct conversion and indirect conversion systems.
In direct conversion, x-ray photons are bombared on photo conductor e.g. amorphous selenium. These are directly converted to electronic signals and amplified/digitized. The direct conversion does not use scintillator. In indirect conversion, scintillator layer converts x-ray photons to photons of visible light. These visible light photons are converted into electrical charge using amorphous silicon as photo diode. Indirect systems are of two types based on use of either TFTs or CCDs.
The information on both direct and indirect type of detectors are read by TFTs (thin film transistors). The figure-1 depicts basic working principle of X-ray imaging system with its components viz. x-ray generator, x-ray detector or image receptor and computer. Image receptor detects and records X-ray images. It is placed below or behind the patient so that X-rays after passing through the patient falls on the image receptor. There are different image recorders used in clinical radiography for diagnostic purposes such as photographic film, storage phosphor screen and direct digital readout device.
Image Courtesy : Carestream Health, Inc.
The figure-2 depicts DRX-Evolution Plus system from Carestream Health Inc. It has wireless detector, table for patients, x-ray overhead tube (motorized) and operator console. Wireless detector is very handy for patients not able to walk and requires X-ray image.
Benefits or advantages of digital radiography
Following are the benefits or advantages of digital radiography for clinical diagnosis:
➨Lower dose of radiation is sufficient to capture digital images than conventional radiography.
➨It is possible to adjust or modify contrast, color and size of the images for proper visibility of body parts.
➨Automated image analysis can be performed using modern data processing algorithms.
➨It avoids all the film processing errors and hazards associated with handling the chemical solutions as used in conventional radiography.
➨Digital radiographs are acquired immediately and in real time.
➨Digital radiographs are stored for long period of time on various digital storage media as per legal requirements in many countries.
➨Digital images are easily and quickly transferred between offices or institutions. This provides immediate and quick treatment to patients. Moreover it avoids additional exposure to the patients.
Drawbacks or disadvantages of digital radiography
Following are the drawbacks or disadvantages of digital radiography:
➨Digital radiography systems are very expensive. It requires computers, servers, storage devices etc.
➨It requires more storage space which depends on image sizes.
➨Digital images are prone to intentional manipulation for any misuse.
➨Most of the storage phosphor systems offer low optimal resolution compare to radiographic film.
➨It requires radiologists to learn and adopt machinery, technology and positioning techniques.