Estudo comparativo de descritor de dose em exames pediátricos de tomografia computadorizada

Finatto, Jerusa D.; Froner, Ana Paula Pastre; Pimentel, Juliana; Silva, Ana Maria Marques da

doi:10.15392/bjrs.v3i1a.126

Cited by 5 publications

(5 citation statements)

References 4 publications

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“…After irradiation, this film became darker and higher doses imply a darker color. Therefore, it can be used to observe dose deposition in CT experiments [8,9,10,11].…”

Section: Methodsmentioning

confidence: 99%

AXIAL DOSE PROFILE IN A HEAD PHANTOM CT SCAN USING A 100 kV X-RAY BEAM

Souza¹,

Santana²,

Santos³

et al. 2023

Anais Da Semana Nacional De Engenharia Nuclear E Da Energia E Ciências Das Radiações

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Computed Tomography (CT) is a diagnostic imaging method and has been widely used in medical applications. CT exams have increased substantially and promote higher dose deposition in population. CT dosimetry references are characterized by Computed Tomography Dose Index (CTDI). In this work was used a set of two head CT phantoms, made of PMMA. The first head phantom is the standard adult, and it is a cylinder with 16 cm in diameter and 15 cm in length, coupled to a complementary cylinder of PMMA with the same diameter and 7,5 in length. In this phantom set, a circular sheet of GAFCHROMIC® XR-QA2 radiochromic film was loaded between the cylinders. A distance of 10 cm of the phantom set was scanned with the film in the central slice position, using an X-ray beam of 100 kV and 200 mA.s. The scanning was made in a CT scanner GE, LightSpeed VCT model with 64 channel. Digital film images were obtained before and after the CT scanning and they were processed with the digital image viewer imageJ software, to obtain the dose variation in the central slice recorded by the film sheet. Dose variation profile were obtained for horizontal and vertical axes (X and Y) of the central slice. The absorbed dose recorded on the film ranged from 18.03 to 30.40 mGy for the X axis and from 21.52 to 33.85 mGy for the Y axis. The dose value obtained in center, where is the intersection of the X and Y axes, was approximately 22.73 mGy. From these values it became possible to calculate the CTDIvol value using radiochromic films.

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“…After irradiation, this film became darker and higher doses imply a darker color. Therefore, it can be used to observe dose deposition in CT experiments [8,9,10,11].…”

Section: Methodsmentioning

confidence: 99%

AXIAL DOSE PROFILE IN A HEAD PHANTOM CT SCAN USING A 100 kV X-RAY BEAM

Souza¹,

Santana²,

Santos³

et al. 2023

Anais Da Semana Nacional De Engenharia Nuclear E Da Energia E Ciências Das Radiações

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“…Figure 3 shows two radiochromic film strips, one not irradiated (a) and another irradiated (b). The processing of their images has been used extensively to measure absorbed doses in patients [8][9][10][11].…”

Section: Methodsmentioning

confidence: 99%

Axial Dose Profile in Head CT Scan Using a 140 kV X-Ray Beam

Prata¹,

Stephanie²

2022

Int J Radiol Imaging Technol

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“…However, radiation doses in CT are generally measured in cylindrical PMMA phantoms, that represent a standard adult patient. These phantoms are designed to simulate a head with 16 cm in diameter, and a body with 32 cm [5,6].…”

Section: Introductionmentioning

confidence: 99%

Dose Evaluation in Head Ct Scans Using a Standard Pmma Phantom

Santos¹,

Reis²,

Filho³

2023

Anais Da Semana Nacional De Engenharia Nuclear E Da Energia E Ciências Das Radiações

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Computed Tomography (CT) is one of the most used exams for radiological diagnosis in medicine. The increase of CT exams is a global concern due to high radiation doses. It is important to improve protocols to seek lower doses while maintaining the diagnostic image quality. The use of phantoms allows the testing of different acquisition protocols. For this, the phantom must present an absorption characteristic of the X-ray beam like the represented patient. In this study, it was used a standard head phantom made of polymethylmethacrylate (PMMA). The phantom is a cylinder with 16 cm in diameter and 15 cm in length. Different acquisition protocols were performed on a Toshiba CT scanner, Aquilion model with 64 channels. The central slice of the phantom was irradiated successively, and using a pencil ionization chamber, measurements of CT air kerma index in PMMA (Ck,PMMA,100) were performed. From these results, the CT Dose Index values weighted and volumetric (CTDIw, CTDIvol) were obtained for 10 cm scans of the central area of the head phantom, in helical mode. The scans were performed using different voltage values (80, 100 and 120 kV) and charge (mA.s). Dose values of CTDIw varied from 2.55 mGy to 7.76 mGy. The absorbed dose (CTDIvol) was 23.67 mGy with the routine protocol used in the radiological service. The pitch of the scans were adjusted and acquisition protocols were tested for each voltage and varying the charge (mA.s). Optimized protocols were approved when the noise in the central slice was less than 1%. The better protocol happens with the voltage of 120 kV and the absorbed dose was reduced in 68.31%. The other parameters tube time, thickness beam and image reconstruction were the same of the routine protocol.

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Estudo comparativo de descritor de dose em exames pediátricos de tomografia computadorizada

Cited by 5 publications

References 4 publications

AXIAL DOSE PROFILE IN A HEAD PHANTOM CT SCAN USING A 100 kV X-RAY BEAM

AXIAL DOSE PROFILE IN A HEAD PHANTOM CT SCAN USING A 100 kV X-RAY BEAM

Axial Dose Profile in Head CT Scan Using a 140 kV X-Ray Beam

Dose Evaluation in Head Ct Scans Using a Standard Pmma Phantom

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