Laura Meterc (Author), Ester Nemeček (Author), Alenka Pilar (Author), Tina Starc (Reviewer), Helena Hribar (Mentor)

Abstract

Uvod: V računalniški tomografiji uporabljamo dva načina zajema podatkov, sekvenčni in spiralni. Sekvenčni način omogoča, z enim obratom rentgenske cevi, pridobivanje posnetkov tolikšnih rezin kolikor vrst detektorjev imamo, vendar je potreben premik pacienta do naslednjega željenega reza po vsaki rotaciji cevi. Spiralni je v razvoju tehnologije z načinom zajema slike prinesel krajše preiskave. Namen: Namen diplomske naloge je opis protokolov sekvenčnega in spiralnega slikanja, razlike med njima ter ovrednotenje odstopanj v dobljenih vrednostih DLP pri obeh načinih zajema, če le-ta obstajajo. Metode dela: Za izdelavo diplomske naloge smo uporabile retrospektivno deskriptivno metodo zbiranja podatkov, izvedenih na 16-reznem aparatu Siemens CT (Computed tomography) Sensation. Analizirale smo 20 posnetkov CT slikanj prsnega koša, 10 posnetkov sekvenčnega HRCT slikanja in 10 spiralnega. Kolmogorov-Smirnov test normalnosti in t-test neodvisnih vzorcev sta pokazala statistično značilne razlike med vrednostmi DLP med obema načinoma slikanja. Rezultati: Z namenom primerjave sevalne obremenitve smo pri analizi uporabile parametre, ki determinirajo dozno obremenitev za pacienta pri CT slikanju; DLP, CTDIvol in dolžina skena. V povprečju je DLP pri spiralnem slikanju za 164 % višji kot pri sekvenci. Kolmogorov-Smirnov test normalnosti je pokazal signifikanco p>0,05, t-test neodvisnih vzorcev pa signifikanco, manjšo od 10-3. Razprava: Spiralno slikanje se v področju prsnega koša uporablja v primerih tumorja, sekvenčno pa za obravnavo intersticijskih bolezni pljuč. Zaradi razlik v vrednostih DLP med sekvenčnim in spiralnim načinom in zelo pogosti uporabi CT slikanj, je pomembna pozornost kadra radioloških inženirjev na vse parametre, ki determinirajo dozno obremenitev za pacienta, skladno z načeli ALARA. Pomembna je ustrezna izbira načina slikanja ter prvovrstno utemeljenost vsakega napotnega slikanja. Naloga je lahko v pomoč pri nadaljnih raziskavah protokolov in doz na področju prsnega koša, njihovo optimizacijo za znižanje sevalnih obremenitev.

Keywords

diplomska dela;radiološka tehnologija;računalniška tomografija;DLP;sekvenčna tomografija;spiralna tomografija;doza;

Data

Language: Slovenian
Year of publishing:
Typology: 2.11 - Undergraduate Thesis
Organization: UL ZF - University College of Health Studies
Publisher: [L. Meterc
UDC: 616-07
COBISS: 5338475 Link will open in a new window
Views: 1788
Downloads: 540
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Other data

Secondary language: English
Secondary title: ǂThe ǂdifferences in dose length product values between sequential and spiral computed tomography scans of thorax
Secondary abstract: Introduction: There are two different ways of collecting data with computed tomography, the sequential and spiral. In the sequential mode a single rotation of the X-ray tube enables to acquire the image of as many numbers of slices as there are different types of detectors, but after every X-ray tube rotation, we have to reposition the patient to the next desired cut. The spiral mode brought a shorter examination time through the development of the computed tomography technology. Purpose: The purpose of our thesis is to describe the protocol for the sequential and spiral imaging, the differences between them and to evaluate obtained differences in acquired values of DLP for both methods of imaging. Methods: We used a retrospective descriptive or descriptive method of collecting data for our thesis, since we obtained our data from previously performed imaging, that was conducted on a 16-slice machine Siemens CT Sensation at University Medical Centre Ljubljana, Institute of Radiology. We will analyse twenty patients referred for thorax CT, half of which (five women, five men) were referred for a sequential CT imaging and the other half for a spiral CT imaging. Results: In interpreting and analysing acquired CT images, we were able to compare the radiation dose that the patients obtained with the help of certain parameters that determine the interpretation of the patient’s dose load at CT imaging; DLP, CTDIvol and the length of the scan. We verified the DLP values that are given on the computer screen at the end of the imaging with the help of a known equation for calculating DLP. In average the DLP in spiral imaging is 164% higher in comparison to sequential imaging. Kolmogorov-Smirnov’s test of normality showed the significance p > 0,05, the t-test for independent samples showed the significance less than 10-3. Discussion: Spiral method of imaging thorax is used in cases of tumours and sequential in discussion about interstitial lung diseases. Because there are significant differences in DLP values between both methods and since CT imaging is an increasingly used diagnostic imaging method, it is important that as radiological engineers we pay attention to all the parameters that determine the patient’s dose load in accordance with ALARA principles. The most important part is choosing suitable method of imaging according to the referred diagnosis and primarily to assure justification of every CT imaging. This research could be used in further examinations of the protocols and doses in thorax area thus their optimisation.
Secondary keywords: diploma theses;radiologic technology;computed tomography;DLP;sequential tomography;spiral tomography;dose;
Type (COBISS): Bachelor thesis/paper
Study programme: 0
Embargo end date (OpenAIRE): 1970-01-01
Thesis comment: Dipl. delo (bolonjski študij), Univ. v Ljubljani, Zdravstvena fak., Oddelek za radiološko tehnologijo
Pages: 17 str.
ID: 10863303