Vpliv zaslanjanja polja na dozno obremenitev pri radiografiji ledvene hrbtenice v anteroposteriorni in stranski projekciji

Šalić, Petar (author), Vodopivec, Tine (author), Medič, Mojca (mentor)

Uvod: Ledvena vretenca imajo velika telesa in dolge stranske odrastke, ki so ostanki reber in jih zato imenujemo processus costarius. Ledvena hrbtenica je podvržena degenerativnim procesom, ki se pričnejo po puberteti in so povezani z nezadostnim metabolizmom medvretenčne ploščice. Najpomembnejše mesto pri diagnostiki ledvene hrbtenice zavzemajo radiološke preiskave, med njimi nativno rentgensko slikanje. Rutinsko opravimo slikanje v anteroposteriorni in stranski projekciji; na tej podlagi določimo anatomijo ledvene hrbtenice. Omejitev rentgenskega snopa je pomembna iz dveh vidikov, in sicer zaradi zmanjšanja izpostavljenosti pacienta nepotrebnemu sevanju in zmanjšanja vpliva sipanega sevanja na kontrastno ločljivost slike. Namen: Primerjati uporabo različnih velikosti obsevalnega polja in vpliv le-teh na prejeto dozo preiskovanca pri dveh osnovnih projekcijah ledvene hrbtenice. Eden izmed namenov je tudi poiskati optimalno velikost snopa rentgenskih fotonov pri slikanju ledvene hrbtenice v obeh osnovnih projekcijah. Metode dela: Merili smo razliko med produktom doze in površine slikanega polja ter vstopno kožno dozo pri različnih velikostih obsevalne površine pri AP in stranskem slikanju ledvene hrbtenice. Kot slikovni sprejemnik smo uporabili CR kaseto, velikosti 35×43 cm, katero smo vstavili vzdolžno v predal mize z radiografsko rešetko. Slikali smo z rentgenskim aparatom Multix/Vertix znamke Siemens z izbrano velikostjo gorišča 1 mm in osnovno filtracijo rentgenskega snopa, ki znaša 2,5 mm aluminija. Merili smo vrednost VKD in DAP na fantomu, ki simulira odraslega moškega. Rezultati in razprava: Skupno smo pridobili 19 različnih velikosti polj pri AP projekciji. Za vsako velikost polja smo izvedli tri meritve in povprečno vrednost DAP in VKD vpisali v tabelo. Enak postopek smo uporabili pri 18 različnih velikostih polj pri lateralni projekciji. Z izvedenimi meritvami smo potrdili DAP v odvisnosti od velikosti slikovnega polja. Z meritvami smo pridobili podatek o optimalni velikosti polja za AP in stransko projekcijo ledvene hrbtenice. VKD se drastično ne spreminja. Zaključek: Dosledno oblikovanje slikovnega polja s pomočjo zaslonk rentgenske cevi na anatomske značilnosti in dejanske velikosti ledvene hrbtenice pri posameznem pacientu zmanjšuje prejeto dozno obremenitev.

• Language: Slovenian
• Keywords: ledvena hrbtenica, rentgenski aparat, AP in stranska projekcija, FOV, DAP, VKD
• Work type: Bachelor thesis/paper
• Organization: ZF - Faculty of Health Sciences
• Year: 2017
• PID: 20.500.12556/RUL-94581
• COBISS.SI-ID: 5338987
• Publication date in RUL: 05.09.2017

Secondary language

• Language: English
• Title: Effect of collimation of X-ray beam and its impact on dose with radiography of lumbar spine in anteroposterior and lateral projection

Abstract

Introduction: Lumbar vertebrae have large bodies and long lateral excrescences which are the remainders of ribs and are therefore called processus costarius. Lumbar spine is susceptible to degenerative processes which start after puberty and are connected with insufficient metabolism of intervertebral disc. The most important part of the lumbar spine diagnostics is native radiology examination. Routine examination is done in anteroposterior and lateral projection; these are the basics to determine lumbar spine anatomy. X-ray beam collimation is important for two reasons, to reduce the patients’ exposure of unnecessary radiation and to reduce the effect of scattered radiation on the image contrast. Purpose: To compare the usage of various sizes of field of views and the effect of them on the received dose of a patient in two basic projections of lumbar spine. One of the purposes is to discover optimal beam size of the x-ray photons at two basic projections of lumbar spine imaging. Methods: We measured the difference between dose area product and entering skin dose at different sizes of radiating surfaces in AP and lateral lumbar spine imaging. CR cassette in the size of 35×43 cm was used as an imaging detector which was inserted longitudinally in the table drawer with the radiographic grid. Images were taken with the Multix/Vertix machine of Siemens brand with chosen size of focus point of 1 mm and basic filtration of the X-ray beam equal to 2,5 mm of Aluminum. We measured the values of DAP and entering skin dose on a phantom that simulates a grown-up man. Results and discussion: We acquired a total of 19 different field sizes for the AP projection. Three different measurements were taken for each field size and the mean result was written in the table. Same procedure was used for 18 different field sizes for the lateral projection. With the measurements we confirmed the DAP dependence on field of view. We acquired the data of optimal field size for AP and lateral projection of lumbar spine with the measurements taken. Entering skin dose was not drastically changed. Conclusion: Consistent formation of FOV with the help of X-ray machine shutters on anatomic charateristics and actual size of lumbar spine at individual patient lowers the dose load.

• Keywords: lumbar spine, x-ray machine, AP and lateral projection, FOV, DAP, entering skin dose