Comparison of different phantom designs for CT scanner automatic tube current modulation system tests

Sookpeng, Supawitoo; Martin, C J; Gentle, David J

doi:10.1088/0952-4746/33/4/735

Cited by 25 publications

(28 citation statements)

References 8 publications

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“…5,8,9,18,19 From those studies, it is concluded that an ideal phantom should be applicable to use for the evaluation of longitudinal as well as angular ATCM and provide a means for quantifying image quality. Sookpeng et al 18 have used phantoms with sharp discontinuities and air gaps, concluding that these properties should be avoided. Further, the phantom should have regions with constant geometry wider than the total beam collimation to allow the modulation to stabilize.…”

Section: Phantommentioning

confidence: 99%

Evaluating the impact of scan settings on automatic tube current modulation in CT using a novel phantom

Merzan¹,

Nowik²,

Poludniowski³

et al. 2017

BJR

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Objective: The aim of this study was to make a comprehensive evaluation of how variable scan settings can affect the performance of automatic tube current modulation (ATCM) in recent CT scanners from the four major manufacturers. Methods: A phantom was designed and manufactured for the purpose of evaluating ATCM. The phantom was scanned with four categories of systematically varied settings (scan projection radiograph, technique and reconstruction parameters and phantom miscentring). The performance of ATCM, in terms of applied tube current and noise uniformity, for the scans with varied settings was compared with a reference scan using subjective and quantitative approaches. Results: The ATCM implemented by each manufacturer is based on different principles and any affect to the performance of the ATCM, when varying scan settings, will manifest differently among the vendors. The results are summarized in four tables corresponding to the categories of varied settings. Conclusion: The developed phantom proved useful for evaluating the ATCM. It is important to understand how different implementations (vendor specific) of ATCM perform in order to make informed decisions about the selection of scan settings when designing protocols. The resulting tables can serve as a reference for understanding the different implementations of ATCM and highlight settings that should be taken into consideration when adjusting an imaging protocol. Advances in knowledge:The results from this work can serve as a reference for how changes in geometry or scan settings can affect the performance of ATCM, in terms of tube current and noise.

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Section: Phantommentioning

confidence: 99%

Evaluating the impact of scan settings on automatic tube current modulation in CT using a novel phantom

Merzan¹,

Nowik²,

Poludniowski³

et al. 2017

BJR

View full text Add to dashboard Cite

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“…The tube current indicated in Table 4 showed a similar trend in various studies. Most studies applied the AEC system to modulate the tube current and reduce unnecessary radiation exposure to their subjects [16][17][18][19][20]. However, the variation in pitch factor and beam collimation showed different approaches taken by various institutions in utilizing their CT-Scanner.…”

Section: Discussionmentioning

confidence: 99%

Radiation Doses and Cancer Risk from CT Pulmonary Angiography Examinations

Harun¹,

Karim²,

Abbas³

et al. 2019

Preprint

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The present study aims to investigate radiation doses from Computed Tomography Pulmonary Angiography (CTPA) examinations based on the patient’s size and to estimate the probability of cancer risk induced from the examination. Data from 100 patients who had undergone CTPA examinations, such as scanning acquisition parameters, patient demography, as well as radiation dose exposure, were collected and analysed. All subjects which aged above 18 y/o were scanned using a Philips Brilliance 128 multi-detector CT (MDCT) scanner. The mean dose value for Volume Computed Tomography Dose Index (CTDIvol), Dose-Length Product (DLP) and effective dose (E) were 11.06 ± 7.17 mGy, 400.38 ± 259.10 mGy.cm and 8.68 ± 5.47 mSv respectively. In addition, with respective of patient’s effective diameter, the mean SSDE value for Group 1, Group 2 and Group 3 were 9.93 ± 3.89, 13.70 ± 9.04 and 22.29 ± 7.35, respectively. Cancer risk per million procedure was calculated based on te recommendation by the International Commission on Radiological Protection Publication 103 report. The organ dose and cancer risk attained for breast, lung and liver were 17.05 ± 10.40 mGy (194 per one million procedure), 17.55 ± 10.86 mGy (192 per one million procedure) and 15.04 ± 9.75 mGy (53 per one million procedure), respectively. In conclusion, CTDIvol underestimated, and SSDE was more accurate in describing the radiation dose. Lung and breast with larger lung effective diameter received the highest dose exposure which increase the probability of the cancer risk. Therefore, it is important to apply optimised protocols in order to reduce patient’s exposure during CTPA examination.

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“…Estudos anteriores mostram que uma redução semelhante de dose nos órgãos em pacientes adultos utilizando o sistema AEC, chegando a 35%, quando comparado com o uso de uma corrente fixa 16 . A otimização de outros parâmetros, como a utilização de um pitch maior, possibilitou reduções de dose de 44% utilizando o AEC para pacientes adultos 8 .…”

Section: Discussionunclassified

Doses em tomografia computadorizada de crânio: impacto do uso do controle automático de exposição

2017

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ResumoO uso de sistemas de redução de dose na tomografia computadorizada é particularmente importante para pacientes pediátricos, que possuem uma alta radiossensibilidade, pois estão em fase de crescimento. O objetivo deste estudo foi avaliar o impacto do uso do sistema AEC Care Dose da Siemens na estimativa de dose em exames de tomografia computadorizada de crânio em pacientes pediátricos. Foi realizado um estudo retrospectivo com 199 exames de tomografia computadorizada de crânio de pacientes pediátricos em diferentes faixas etárias, em um tomógrafo Siemens Emotion de 16 canais. Foi possível observar, para todas as faixas etárias, que o uso do sistema AEC Care Dose não apenas reduz o CTDIvol, mas também a amplitude interquartil, reduzindo a dose total na população investigada. Conclui-se que o sistema AEC Care Dose modela a corrente de tubo de acordo com as dimensões do paciente, sendo possível a redução da dose individual e coletiva, sem afetar a qualidade do diagnóstico. Palavras-chave: dosimetria; tomografia computadorizada; controle automático de exposição; Care Dose. Abstract The use of dose reduction systems in computed tomography is particularly important for pediatric patients IntroduçãoExiste um consenso na literatura sobre as altas doses que os pacientes pediátricos recebem a partir de um exame de tomografia computadorizada (TC), e que podem resultar em um aumento do risco de carcinogênese induzida por radiação 1-3 .Pesquisadores vem estudando uma forma mais realística de estimar a dose em TC, considerando o tamanho específico 4,5 e o peso do paciente 6 . Diversos estudos tem demostrado que o uso do controle automático de exposição ou AEC (Automatic Exposition Control) 7-9 e/ou modificações na tensão do tubo de raios X, pitch 10 e espessura do corte, podem reduzir a dose no paciente, sem afetar significativamente a qualidade da imagem 11 .O descritor CTDIvol (Volumetric Computed Tomography Dose Index) é uma estimativa de dose padronizada em exames de TC, que utiliza um simulador cilíndrico padrão de 32 cm ou 16 cm, dependendo da faixa etária e/ou região do corpo 12 . Tais valores, no entanto, representam apenas uma aproximação da dose absorvida pelo paciente e dependem dos parâmetros selecionados de aquisição, sem considerarem as características antropométricas dos pacientes.Atualmente, os equipamentos mais modernos de TC possuem sistemas de AEC, que possibilitam a modulação da corrente no tubo de raios X, conforme a variação de espessura do paciente. As diferenças de densidade dos tecidos que compõem a região imageada também interferem na qualidade do contraste da imagem. O sistema AEC busca determinar uma fluência de fótons ideal para cada paciente e cada região anatômica analisada 13 . Cada um dos sistemas AEC implementados pelos fabricantes possui especificações diferentes e opera de forma distinta 14 A fabricante Siemens desenvolveu um sistema AEC denominado Care Dose, que estima a atenuação dos raios X nos planos x e y em cada corte, durante uma rotação. O sistema utiliza tais informações para...

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Comparison of different phantom designs for CT scanner automatic tube current modulation system tests

Cited by 25 publications

References 8 publications

Evaluating the impact of scan settings on automatic tube current modulation in CT using a novel phantom

Evaluating the impact of scan settings on automatic tube current modulation in CT using a novel phantom

Radiation Doses and Cancer Risk from CT Pulmonary Angiography Examinations

Doses em tomografia computadorizada de crânio: impacto do uso do controle automático de exposição

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