Medical DR equipment is currently the mainstream X-ray inspection method, which has many advantages such as fast imaging, convenient storage and easy image post-processing, and has gradually replaced traditional X-ray machines. However, in practice, there are still some problems with the image quality of medical DR equipment, such as poor image contrast, unclear images, excessive noise, and asymmetric image brightness. Once the image quality of DR equipment is poor, it may cause missed diagnosis, misdiagnosis, or damage to the examiner’s organism due to improper dose, so ensuring the image quality of medical DR equipment should be a top priority.
Perlove Medical has summarised the following factors that affect the image quality of medical DR equipment
The image quality of the various detectors in medical DR equipment is measured in terms of resolution and DQE (quantum capture efficiency), which in turn is the primary measure, characterising the dose efficiency of the imaging system. It combines many factors such as system contrast, image resolution and the effect of noise, and measures the performance of the noise/signal-to-image conversion of the input X-rays.
DQE indicates the ratio retained by a digital X-ray imaging device in converting a radiographic image into a digital image image signal-to-noise ratio. In the field of X-ray imaging, the noise of the radiographic image is closely related to the exposure dose, and the DQE value likewise expresses the efficiency of the digital imaging device in utilising the incident dose. The exposure dose is in turn linked to the health of the person in contact with it, so the DQE value is an important technical indicator for testing digital medical X-ray diagnostic equipment. Only with a reasonable choice of DQE indicators can we obtain the desired image quality and make the application of medical DR equipment technology more advantageous.
Digital images consist of pixels, which are arranged in rows or columns in the form of a matrix. Each pixel has its own grey scale, which creates the different shades that we can identify in the image. The size of each pixel in a digital image determines the spatial resolution of the image, i.e. the smallest object we can find in the image.
Overall, the more pixels the better the image resolution, but it does not mean that the image quality is better. For our imaging system, when the pixels are high beyond a certain point, the image quality is rather less than excellent, mainly because the more pixels we use, the more photographic elements we use, and the same size of the flat panel will make the photographic elements smaller, and each photographic element will receive less photoelectronic information, so it cannot form a very good image. Moreover, the more sensors used, the higher the cost. Hardware and illumination conditions can affect the image, so don’t go for the very high pixel count.
The signal-to-noise ratio of a digital image, i.e. the ratio of image signal to noise. Generally speaking, the larger the signal-to-noise ratio, the smaller the image noise, the better the image quality, i.e. the clearer it is; conversely, the smaller the signal-to-noise ratio, the larger the image noise, the poorer the image quality and the rougher it looks. However, the signal-to-noise ratio can be adjusted by changing the illumination conditions. Increasing the illumination conditions (increasing kilovolts or milliamperes) will increase the signal-to-noise ratio, but if the illumination conditions are smaller, the image signal-to-noise ratio will be smaller and the image noise will be higher, i.e. it will look grainy and rougher.
Medical DR equipment has a powerful image post-processing function, the diagnostician can adjust the image contrast and other parameters according to the specific conditions of the patient, and then through a series of image post-processing technology (such as automatic image processing technology, edge enhancement clear technology, magnification roaming, window width and window position adjustment of the area of interest, as well as distance, area, density measurement and other rich functions), from which a wealth of reliable clinical diagnosis This provides a reliable diagnostic basis for the diagnosis of diseases, especially for the detection of early lesions.
For example, Perlove Medical has developed and produced a large field of view flat panel dynamic DR (model: PLX8600), which uses the company’s self-developed tissue equalisation technology, which is based on a multi-layer graded detail equalisation algorithm that extends from low grey areas to high grey areas. For human body images, after the tissue equalization, the details of the image can be highlighted clearly, and the texture of the lung texture end of the tiny blood vessels and the texture of the bones and muscle levels can be clearly displayed.
In addition, there are other factors that can affect the image quality of medical DR equipment, such as human operation, the environment of the machine room, and the DR equipment itself.