Comparison of central, peripheral, and weighted size-specific dose in CT

Anam, Choirul; Adhianto, Dwi; Sutanto, Heri; Adi, Kusworo; Ali, Mohd Hanafi; Rae, William; Dougherty, Geoff

doi:10.3233/xst-200667

Cited by 12 publications

(5 citation statements)

References 35 publications

(49 reference statements)

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“…However, the diameter of the head of every patient fluctuates along the z-axis, and an accurate estimate of organ dose should consider this fluctuation. The SSDE along the z-axis depends on D w in fixed tube current (FTC) and depends on both D w and tube current in tube current modulation (TCM) [27]. A previous study [28] reported estimated the TLD measurements were about 16% [28].…”

Section: Discussionmentioning

confidence: 99%

“…However, the dose distribution in the center of a 16 cm PMMA phantom was reported to be similar to the dose at the periphery [26]. In another study, Anam et al [27] explored various physical sizes of acrylic phantoms within a range of 8-32 cm and reported that D w within a range of 12-14 cm had a homogeneous dose distribution for both central and peripheral regions. Therefore, the SSDE may be useful for organ dose estimation within the head region without any consideration of fluctuations in the radial dose distribution.…”

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confidence: 97%

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Investigation of Eye Lens Dose Estimate based on AAPM Report 293 in Head Computed Tomography

Anam

Dewi

Basri³

et al. 2021

J Biomed Phys Eng

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Background: Estimation of eye lens dose is important in head computed tomography (CT) examination since the eye lens is a sensitive organ to ionizing radiation. Objective:The purpose of this study is to compare estimations of eye lens dose in head CT examinations using local size-specific dose estimate (SSDE) based on size-conversion factors of the American Association of Physicists in Medicine (AAPM) Report No. 293 with those based on size-conversion factors of the AAPM Report No. 220. Material and Methods:This experimental study is conducted on a group of patients who had undergone nasopharyngeal CT examination. Due to the longitudinal (z-axis) dose fluctuation, the average global SSDE and average local SSDE (i.e. particular slices where the eyes are located) were investigated. All estimates were compared to the measurement results using thermo-luminescent dosimeters (TLDs). The estimated and measured doses were implemented for 14 patients undergoing nasopharyngeal CT examination. Results:It was found that the percentage differences of the volume CT dose index (CTDI vol ), average global SSDE based on AAPM No. 220 (SSDE o,g ), average local SSDE based on AAPM No. 220 (SSDE o,l ), average global SSDE based on AAPM No. 293 (SSDE n,g ) and average local SSDE based on AAPM No. 293 (SSDE n,l) against the measured TLD doses were 22.5, 21.7, 15.0, 9.3, and 2.1%, respectively. All comparisons between dose estimates and TLD measurements gave p-values less than 0.001, except for SSDE n,l (p-value = 0.566). Conclusion: SSDE based on AAPM ReportNo. 293 can be used to accurately estimate eye lens radiation doses by performing the calculations on a number of specific slices containing the eyes.

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 97%

Investigation of Eye Lens Dose Estimate based on AAPM Report 293 in Head Computed Tomography

Anam

Dewi

Basri³

et al. 2021

J Biomed Phys Eng

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show abstract

“…Para simplificar esta cuestión, hemos supuesto que CTDI ∝ D ∝ e −µd y utilizando la relación entre el CTDI periférico (CTDI p ) y el CTDI central (CTDI c ) como CTDI p CTDI c = k , descrita por Choirul et al, 8 hemos llegado a la siguiente expresión, en una primera aproximación, para el coeficiente de atenuación efectivo según el equipo utilizado:…”

Section: Coeficiente De Atenuación Lineal Efectivo µunclassified

Modelo de ajuste del perfil de dosis de un TC sobre un maniquí estandar de cabeza de PMMA

Martínez¹,

Gomez²

2023

Rev Fis Med

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Propósito/Objetivo: En el presente trabajo se expone un modelo para el perfil de dosis depositada en un maniquí estándar de 16 cm de diámetro y 15 cm de longitud fabricado con “polimetil metacrilato” (PMMA) en un equipo de tomografía computarizada o TC. Método: El modelo propuesto es un modelo sencillo de ajuste basado en funciones error y gaussianas, justificando en este trabajo de manera sencilla algunos de los parámetros utilizados en el mismo. Los datos utilizados para el desarrollo del modelo han sido obtenidos con un detector de estado sólido incorporado en una sonda para la medida del perfil en el eje del maniquí. Resultados y discusión: hemos encontrado una buena aproximación a los datos experimentales con el modelo propuesto, además de su gran versatilidad debido a la gran variedad de mediadas experimentales utilizadas, con diferentes equipos y parámetros de adquisición, para su elaboración. Conclusiones: Este modelo ajusta bien los perfiles de deposición de dosis generados sobre un maniquí de cabeza en su eje central. Puede ser considerado como base para llevar a cabo correcciones experimentales, determinaciones dosimétricas y otras consideraciones que necesiten de un modelo teórico del perfil de dosis.

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“…The X-ray attenuation is a fundamental parameter effecting X-ray absorption and the dose absorbed by patient. The patient characteristics are generally represented by the water-equivalent diameter (D W ) [15,16] of the patient. Its value can be determined from patient images [7,17,18].…”

Section: Introduction mentioning

confidence: 99%

Comparisons of Water-Equivalent Diameter Measured on Images of Abdominal Routine Computed Tomography with and without A Contrast Agent

et al. 2021

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The size-specific dose estimate (SSDE) is a metric for an estimation of patient dose in computed tomography (CT). The SSDE strongly depends on the water-equivalent diameter (D W ). In abdominal CT examinations, a contrast agent is sometimes used to more clearly visualize tissue lesions. The Hounsfield unit (HU) of CT images with and without the use of a contrast agent at specific areas is slightly different and it may affect the D W value. This study aimed to compare the D W values calculated from axial CT images in patients who had undergone routine abdominal scans both with and without the use of a contrast agent. Axial images of 144 patients with a weight range of 3.5 kg to 90 kg who had undergone routine abdominal scans both with and without the use of a contrast agent using a Siemens Sensation 64 CT scanner were retrospectively collected. The D W values were automatically calculated using the Matlab-based IndoseCT (version 15a) software. The results show the percentage difference between D W,contrast and D W,non-contrast is below 2 %. As a result, the mean SSDE contrast is 1.5 % smaller than SSDE non-contrast . Due to the effect of a contrast agent on the D W and SSDE values is below 2 %, the axial images of CT abdomen without the use of a contrast agent can be used as the accurate estimation of D W and SSDE for images with the use of a contrast agent.

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Comparison of central, peripheral, and weighted size-specific dose in CT

Cited by 12 publications

References 35 publications

Investigation of Eye Lens Dose Estimate based on AAPM Report 293 in Head Computed Tomography

Investigation of Eye Lens Dose Estimate based on AAPM Report 293 in Head Computed Tomography

Modelo de ajuste del perfil de dosis de un TC sobre un maniquí estandar de cabeza de PMMA

Comparisons of Water-Equivalent Diameter Measured on Images of Abdominal Routine Computed Tomography with and without A Contrast Agent

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