Dose Optimization and Reduction in CT of the Brain and Head and Neck Region

Mulkens, T; Salgado, Rodrigo; Bellinck, P

doi:10.1007/174_2011_451

Cited by 5 publications

(9 citation statements)

References 65 publications

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“…Computed Tomography (CT) scanning with the ability to perform scans in a very short time alongside high image quality has become a common imaging modality in diagnostic radiology [1]. The use of this imaging modality dramatically has increased in recent years by the emergence of multidetector CT scanners (MDCT), about 12-fold in the UK and more than 20-fold in the USA in last 25 years [2].…”

Section: Introductionmentioning

confidence: 99%

Establishment of diagnostic reference levels arising from common CT examinations in Semnan County, Iran

Khoramian

Sistani

Hejazi

2019

Polish Journal of Medical Physics and Engineering

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Objective: The literature has approved that the use of the concept of diagnostic reference level (DRL) as a part of an optimization process could help to reduce patient doses in diagnostic radiology comprising the Computed Tomography (CT) examinations. There are four public/governmental CT centers in the province (Semnan, Iran) and, to our knowledge, after about 12 years since the launch of the first CT scanner in the province there is no dosimetry information on those CT scanners. The aim of this study was to evaluate CT dose indices with the aim of the establishment of the DRL for head, chest, cervical spine, and abdomen-pelvis examinations. Methods: Scan parameters of 381 patients were collected during two months from 4 CT scanners. The CT dose index (CTDI) was measured using a calibrated ionization chamber on two cylindrical poly methyl methacrylate (PMMA) phantoms. For each sequences, weighted CTDI (CTDIw), volumetric CTDI (CTDIv) and dose length product (DLP) were calculated. The 75th percentile was proposed as the criterion for DRL values. Results: Proposed DRL (CTDIw, CTDIv, DLP) for the head, chest, cervical spine, and abdomen-pelvis were (46.1 mGy, 46.1 mGy, 723 mGy × cm), (13.8 mGy, 12.0 mGy, 377 mGy × cm), (40.0 mGy, 40.0 mGy, 572 mGy × cm) and (14.9 mGy, 12.1 mGy, 524 mGy × cm), respectively. Conclusion: Comparison with the others results from the other countries indicates that the head, chest and abdomen-pelvis scans in our region are lower or in the range of the other studies investigated in terms of dose. In the case of cervical spine scanning it’s necessary to review and regulate scan protocols to reach acceptable dose levels.

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Section: Introductionmentioning

confidence: 99%

Establishment of diagnostic reference levels arising from common CT examinations in Semnan County, Iran

Khoramian

Sistani

Hejazi

2019

Polish Journal of Medical Physics and Engineering

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“…Kualitas citra CT Scan dapat diukur dengan parameter seperti akurasi CT number, noise, Contrast to Noise Ratio (CNR), dan resolusi spasial. Dibanding dengan modalitas pencitraan lain, CT Scan memberikan radiasi dosis yang tinggi ke pasien, yang dapat memicu kanker [1,2] . Pemeriksaan rutin CT Scan thorax memberikan dosis 100 kali lebih besar dibanding pemeriksaan rutin thorax radiografi [3] .…”

Section: Abstrakunclassified

“…CT number merupakan angka yang menyatakan nilai koefisien atenuasi objek yang dicitrakan relatif terhadap koefisien atenuasi air, seperti pada persamaan 1. Nilai CT number bervariasi dari mulai 500-3000 HU untuk tulang, 0 untuk air, hingga -300 --800 untuk paru paru [2] . Evaluasi CT number dilakukan dengan memindai bagian modul homogen dari fantom yang terbuat dari bahan setara air.…”

Section: Gambar 1 Fantom Qa Ct Scanunclassified

The Effects Of High Dose and Low Dose Protocols In Thorax’s CT Scan Image Quality

Sari

Bahagia

Hartoyo

et al. 2021

Indonesian J Appl Phys

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ABSTRACTThe aim of this research was to evaluate the effects of two different dose protocols’ usage on image quality. This research was performed on three different CT Scanners using high dose and low dose protocols of thorax scan. Different exposure parameters were used, depending on each scanner’s setting. GE QA CT Scan phantom was used for image quality assessment. Image quality measured were CT number accuracy, uniformity and linearity, noise uniformity, spatial resolution and Contrast To Noise Ratio (CNR). CT Scan’s dose index, CTDIvol (Volumetric Computed Tomography Dose Index), was also measured to evaluate how these two protocols work in reducing radiation dose. The result showed that the usage of low dose protocols reduce the CTDIvol value at 85-91% compared to the high dose protocols, meanwhile most of the image quality parameters obtained from both protocols were still considered good. The CT number accuracy, uniformity, linearity and noise uniformity for all CT Scans were all still inside BAPETEN’s (Indonesia National Regulator Agency) threshold. There were 20-23% difference on the spatial resolution value measured from both protocols. The most significant difference came from CNR. The CNR obtained from high dose protocols were 65-93% higher than the one from low dose protocols. Keywords: contrast to noise ratio, CTDIvol, CT number, spatial resolutionABSTRAKPenelitian ini mengevaluasi pengaruh penggunanaan protokol dosis tinggi dan protokol dosis rendah terhadap kualitias citra dan dosis khususnya pada pemeriksaan CT Scan thorax. Penelitian ini dilakukan pada 3 sampel CT Scan yang berbeda. Faktor eksposi yang digunakan berbeda untuk tiap scanner, bergantung pada setting yang terdapat pada scanner. Fantom yagdigunakan untuk menilai kualitas citra adalah fantom GE QA CT Scan. Adapun kualitas citra yang diukur adalah keseragaman, akurasi, dan linearitas CT number, keseragaman noise, resolusi spasial, serta Contrast to Noise Ratio (CNR). Sementara dosis radiasi yang diamati adalah CTDIvol (Volumetrik Computed Tomography Dose Index) yang tampil pada konsol. Hasil penelitian ini menunjukkan bahwa penggunaan protokol dosis rendah mampu mengurangi nilai CTDIvol sebesar 85-91% dibanding dengan protokol dosis tinggi, sementara sebagian besar parameter kualitas citra yang diukur masih dinilai baik. Nilai akurasi, keseragaman, dan linearitas CT number serta keseragaman noise pada protokol dosis tinggi dan dosis rendah, keseluruhannya masih dalam batas ambang BAPETEN. Terdapat perbedaan sebesar 20-23% pada nilai resolusi spasial yang terukur dari kedua protokol. Nilai CNR pada protokol dosis tinggi lebih baik dari pada protokol dosis rendah, dengan perbedaan yang cukup signifikan, yaitu 65-93%.Kata kunci: contrast to noise ratio, CTDIvol, CT number, resolusi spasial

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“…The importance of CT dosimetry is due to the fact that the CT scan contributes to the main portion of the cumulative dose in many countries (about 67% in the US and 68% in the UK), as well as a growing number of CT exams (about 12-fold in the UK and more than 20-fold in the US [8,9]), after the introduction of multi-detector CT (MDCT) scanners that make CT scanning an easy and fast imaging modality and provide better image quality [10]. Also, in comparison to other X-ray-based imaging techniques, CT scan delivers a greater dose to patients [11]. For example, a routine chest CT scan delivers about 100 times (or higher) the dose relative to a routine chest conventional radiography [12].…”

Section: Introductionmentioning

confidence: 99%

“…Various local and national studies on CT dosimetry indicate that head and neck CT examinations are very common imaging protocols [17] and overall comprise about 25 to 30% of all CT procedures [8,11]. Pantos et al [18] reviewed 42 CT dosimetry publications and indicated the wide range (0.3-8.2 mSv) of the ED from head CT examinations.…”

Section: Introductionmentioning

confidence: 99%

Assessment and comparison of radiation dose and image quality in multi-detector CT scanners in non-contrast head and neck examinations

Khoramian¹,

Sistani²,

Firouzjah³

2019

Pol J Radiol

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Purpose To assess and compare radiation dose and image quality from non-contrast head and neck computed tomography (CT) examinations from four different multi-detector CT (MDCT) scanners. Material and methods Four CT scanners with different numbers of detector rows including one 4-MDCT, a 6-MDCT, a 16-MDCT, and a 64-MDCT were investigated. Common CT dose descriptors including volumetric CT dose index (CTDIv), dose length product (DLP), and the effective dose (ED), and image quality parameters include image noise, uniformity, and spatial resolution (SR) were estimated for each CT scanner with standard tools and methods. To have a precise comparison between CT scanners and related doses and image quality parameters, the ImPACT Q-factor was used. Results Minimum and maximum CTDIv, DLP, and ED in the head scan were 18 ± 3 and 49 ± 4 mGy, 242 ± 28 and 692 ± 173 mGy × cm, 0.46 ± 0.4 and 1.31 ± 0.33 mSv for 16-MDCT and 64-MDCT, respectively. And 16 ± 2 to 27 ± 3, 286 ± 127 to 645 ± 79 and 1.46 ± 0.65 to 3.29 ± 0.40 for neck scan, respectively. The Q-factor in head scan was 2.4, 3.3, 4.4 and 5.6 for 4-MDCT, 6-MDCT, 16-MDCT and 64-MDCT, respectively. The Q-factor in neck scan was 3.4, 4.6, 4.7 and 6.0 for 4-MDCT, 6-MDCT, 16-MDCT and 64-MDCT, respectively. Conclusions The results clearly indicate an increasing trend in the Q-factor from 4-MDCT to 64-MDCT units in both head and neck examinations. This increasing trend is due to a better SR and less noise of images taken and/or fewer doses in 64-MDCT.

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Dose Optimization and Reduction in CT of the Brain and Head and Neck Region

Cited by 5 publications

References 65 publications

Establishment of diagnostic reference levels arising from common CT examinations in Semnan County, Iran

Establishment of diagnostic reference levels arising from common CT examinations in Semnan County, Iran

The Effects Of High Dose and Low Dose Protocols In Thorax’s CT Scan Image Quality

Assessment and comparison of radiation dose and image quality in multi-detector CT scanners in non-contrast head and neck examinations

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