Vpliv oddaljenosti ledvenih vretenc na velikost le-teh na rentgenogramu pri slikanju v AP in stranski projekciji : diplomsko delo

Klančar, Kaja (author), Krivograd, Ula (author), Medič, Mojca (mentor), Mekiš, Nejc (reviewer)

Uvod: Pri diagnostiki ledvene hrbtenice opravimo za rutinsko slikanje anteroposteriorno in stransko projekcijo. Rentgenogrami dobro prikažejo število ledvenih segmentov in degenerativne spremembe. Rentgensko slikanje ledvene hrbtenice povezujejo z najvišjimi vrednostmi vstopne kožne doze (VKD). Namen: Želeli smo ugotoviti, kakšen je vpliv oddaljenosti ledvenih vretenc od slikovnega sprejemnika na velikost le-teh na rentgenogramu pri slikanju v AP in stranski projekciji. Eden izmed namenov je tudi raziskati, kako se VKD spreminja pri spreminjanju razdalje ledvene hrbtenice od slikovnega sprejemnika. Metode dela: V teoretičnem delu smo uporabili deskriptivno metodo, pri praktičnem delu pa fantom medenice in ledvene hrbtenice. Centralni žarek smo postavili v višino četrtega ledvenega vretenca. Pri izvajanju meritev smo spreminjali razdaljo objekt– slikovni sprejemnik (ROS), in sicer tako da smo fantom podlagali s ploščami stiroporja. Pred izvedbo meritev smo z metrom izmerili ROS. Pri vsaki spremembi ROS smo nato na rentgenogramu izmerili, kakšna je velikost zgornjega in spodnjega roba telesa tretjega ledvenega vretenca ter izračunali faktor povečave. Izračunali smo tudi, kako se spreminja VKD pri vsaki spremembi razdalje ledvenih vretenc od slikovnega sprejemnika. Rezultati: S povečanjem ROS pri AP projekciji je bila povečava vretenca glede na povprečno razliko med zgornjim in spodnjim robom vretenca 23 %, izračunan faktor povečave pa 21,3 %. VKD se med ROS 17 in 32 cm poveča za 1,69 mGy (79 %). S povečevanjem ROS pri stranski projekciji je bila povečava ledvenega vretenca glede na povprečno razliko med zgornjim in spodnjim robom 22,5 %, izračunan faktor povečave pa 22,7 %. VKD se med ROS 20 in 35 cm poveča za 4,07 mGy (110 %). Razprava in zaključek: Na podlagi zbranih rezultatov smo potrdili, da debelina pacienta pri slikanju ledvenih vretenc v AP in stranski projekciji vpliva na oddaljenost objekta od slikovnega sprejemnika in posledično tudi na velikost vretenc na rentgenogramu. Potrdili smo tudi, da se VKD pri povečevanju ROS v AP in stranski projekciji povečuje.

• Language: Slovenian
• Keywords: diplomska dela, radiološka tehnologija, distorzija, ledvena hrbtenica, razdalja objekt–slikovni sprejemnik, rentgenogrami, vstopna kožna doza
• Work type: Bachelor thesis/paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: ZF - Faculty of Health Sciences
• Place of publishing: Ljubljana
• Publisher: [K. Klančar, U. Krivograd]
• Year: 2020
• Number of pages: 41 str.
• PID: 20.500.12556/RUL-118683
• UDC: 616-07
• COBISS.SI-ID: 26947843
• Publication date in RUL: 30.08.2020

Secondary language

• Language: English
• Title: Magnification error in radiographs of the lumbar spine in AP and lateral projection : diploma work

Abstract

Introduction: Diagnostic procedure for lumbar spine routine imaging is comprised of anteroposterior (AP) and lateral projection. Radiographs show the number of lumbar segments and degenerative changes very well. Lumbar spine radiography is associated with the highest entrance skin dose (ESD) values. Purpose: The purpose is to determine how distance between lumbar vertebrae and image receptor affects the image size of the lumbar vertebrae in AP and lateral projection. We also wanted to know how ESD varies when the distance between lumbar spine and image receptor changes. Methods: The theoretical part was obtained by a descriptive method. In the practical part we used the phantom of pelvis and lumbar spine. Central ray was placed at the level of the fourth lumbar vertebra. During measurements we were changing object to image receptor distance (OID) by putting plates of polystyrene under the phantom. We started our measurements by measuring the OID. At each OID the image size of upper and lower margin of the third lumbar vertebra was measured. Magnification error was theoretically calculated. We also calculated how ESD changes with each change in distance of the lumbar vertebrae from the image receptor. Results: When increasing OID in AP projection the image size of the vertebra increased by 23 % according to the average difference between upper and lower vertebral margin. Theoretically calculated magnification error was 21.3 %. When increasing OID from 17 to 32 cm, ESD increased by 1.69 mGy (79 %). When increasing OID in lateral projection the image size of the vertebra increased by 22.5 % according to the average difference between upper and lower vertebral margin. Theoretically calculated magnification error was 22.7 %. When increasing OID from 20 to 35 cm, ESD increased by 4.07 mGy (110 %). Discussion and conclusion: According to the results patient thickness affects the distance of the object from the image receptor and it also consequently affects the image size of lumbar vertebra. We also confirmed the findings that ESD increases with increasing OID in AP and lateral projection.

• Keywords: diploma theses, radiologic technology, distortion, lumbar spine, object to image receptor distance, radiographs, entrance skin dose