ABSTRACT
Over time, imaging systems have become highly specialized with a broad spectrum of X-ray-related modalities. Key characteristics of the X-ray sources largely dier with respect to X-ray spectra, mechanical interfaces, and energy throughput. To optimize instantaneous and long-term power ratings, ranges of the tube voltage, mechanical interfaces, positions of operation, speed of clinical work ow, and other important features, vendors have been forced to supply and service an estimated number of more than 500 dierent X-ray tube types, which are currently on the market. is chapter will focus on
• Computed tomography (CT) • Interventional cardiac and vascular X-ray (CV)
• Interventional surgical X-ray imaging • Single exposure and uoroscopic standard radiography, remote con-
trolled and nearby controlled • Mammography, including mammography with slit technology • Mobile X-ray • Surgical C-arm X-ray imaging
Figure 5.1 characterizes the modalities by parameters, which to a large extent determine dimension, weight, and costs of the used X-ray tubes. e maximal tube voltage on the abscissa indicates the size of the insulation materials and the dimension of the vacuum gaps between electrodes on dierent potentials, as well as the thickness and mass of radiation shields. e energy per patient on the ordinate characterizes the size of the rotating anode tubes and, in combination with the patient frequency,
Figure 5.1 X-ray systems classied by key characteristics of the X-ray source. Tube voltages are indicated on the abscissa. e ordinate represents the energy per time period, which is required for X-ray generation in most practical cases and for the most popular systems. For CT, mammo (mammography) and general radiography including mobile systems, the integration period is dened as the X-ray on time it takes to image a single patient. e energy is the product of tube voltage, tube current, and the exposure time for the integration period. e indicated patient frequency allows assessment of the average power consumed. Cardiovascular interventional imaging is somewhat special. A mix of minute-long series of uoroscopic low-energy exposures is interleaved with a series of high-power shots. e energy value is stated for every 5 min of an average interventional procedure, which represents about the time constant for anode cooling of the most relevant X-ray sources and the way in which such equipment is used in practice. Rectangles represent the vast majority of practical use cases.
