Introduction: The use of computed tomography in medical diagnostics is increasing. CT is a diagnostic cross-sectional imaging of an object from both transmission or reflection data collected by illuminating the object from many different directions. The advantage of this method is that it gives high contrast resolution and display of low contrast structures. Aim: Computed tomography provides two methods of data collection: the sequential and spiral. The aim of the thesis is to compare the technical parameters and radiation dose between sequential and spiral mode of data acquisition with computed tomography imaging of the head and to identify any differences. Furthermore, we want to determine in which cases the doctor chooses to use the sequence or spiral data acquisition of head imaging. Methods: Descriptive method with systematic review of the literature is used in the thesis. When searching sources and literature, a time frame, from 1993 to 2015, was used. The literature was searched in Slovenian and English. Statistical analysis of the dose-lenght product and the product of tube current and exposure time of spiral and sequential techniques were performed using the computer program SPSS Statistics IBM 22.0 and statistical tests. Data were obtained from computerised tomography device Siemens SOMATOM Sensation 16. Investigations were carried out on fourteen patients during the period from 30 November to 3 December and according to the protocols for sequential and spiral head imaging, which are used on a daily basis. Results: Research results showed that the dose-length product is rather constant in a sequential technique. In a spiral technique the radiation dose received by the patient, and the value of the product of current and time are also fairly constant. Dose burden is affected mainly by the choice and adaptation of the protocol and partly by the constitution or age of the patient. Our findings were confirmed by statistical analysis, which proved the differences between spiral and sequential data acquisition. The dose-lenght product in the sequential technique is lower in comparison with the dose-lenght product in the spiral technique. The product of tube current and exposure time is lower in the spiral technique compared to the sequential technique Discussion and Conclusion: Spiral technique is used in head injuries, which helps surgeons, as it allows 3D reconstruction. The sequential technique is used in routine checks, when there is no need for specific reconstructions. As CT scans represent a large share of dose burdens on patients, the radiation dose should be monitored for its potential reduction. The research could lead to further examination of doses and protocols, and thus their optimisation.
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