Новые возможности в Компьютерной Томографии с model

Новые возможности в
Компьютерной Томографии
с model-based итеративной
реконструкцией
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Об оценке радиационной безопасности населения
при медицинском облучении и эффективности
санитарного надзора
• Суммарное количество всех диагностических
рентгенорадиологических процедур в России в 2012
году достигло 241 млн. и наблюдается устойчивый
рост: на 40% за последние 10 лет
• Наибольший вклад в коллективную дозу медицинского
облучения пациентов в 2012 году внесли
рентгенографические исследования - 34 % (при объеме
исследований в 64%) и КТ - 30 % (при объеме
исследований в 2%)
• За 10 лет вклад компьютерной томографии в
коллективную дозу медицинского облучения вырос в 3
раза.
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Iterative Model-Based Reconstruction
A New Era of CT Image Quality
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По данным измерения на фантоме Catphan 500
3T МРТ
Диагностированное поражение на КТ, подтвержденное на МРТ у того же пациента
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Virtually Noise-Free Images
Revealing Critical Information
73 - 90%
Noise Reduction*
Standard
Reconstruction
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* Image noise as defined by IEC standard 61223-3-5. Image noise was assessed using a Reference Chest Protocol, on a phantom. Data on file.
Improve low-contrast detectability
Detect Small and Subtle Differences
0.68 mm slice thickness
0.68 mm slice thickness
Standard Reconstruction
(FBP)
80 kVp, 500 mAs, 9.8 mGy, 170.5 mGy×cm, 2.5 mSv (k=0.015*)
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Courtesy: Guangdong General Hospital, China
* Low-contrast detectability was assessed using a Reference Abdomen Protocol, on the MITA IQ phantom, using human observers. Data on file.
* AAPM technical report 96
*
Virtually Noise-Free Images*
Standard
Reconstruction
*In clinical practice, IRT may reduce image noise depending on the clinical task, patient size, anatomical location, and clinical practice. A consultation with a radiologist and a physicist should be made to determine the appropriate
dose to obtain diagnostic image quality for the particular task. As with any imaging reconstruction, the quality of the resulting IRT images is dependent on the scanning parameters required for your particular patient, clinical
indication, and clinical practice.
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Standard reconstruction
IMR
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7 month old Abdomen
Standard Reconstruction
IMR
Standard Reconstruction
IMR Level 3
80 kVp, 70 mAs, Coverage 29.4 cm,
CTDIvol 1.5 mGy, DLP 51.5 mGy×cm,
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Courtesy of University of Maryland Medical Center
Pediatric Soft Tissue Neck
Standard Reconstruction
IMR Level 3
80 kVp, 151mAs/slice, Coverage 15.3 cm,
CTDIvol 3.0 mGy, DLP 45.9 mGy×cm, Effective Dose 0.5 mSv (k=0.021)*,
* AAPM technical report 96
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Cardiac
100 kVp, 150 mAs/slice,
CTDIvol 7.1 mGy, DLP 92.0 mGy×cm, Effective Dose 1.2 mSv (k=0.014)*,
* AAPM technical report 96
Courtesy of: MT. Sinai
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Abdomen
3 mm slice
Standard Reconstruction
3 mm Slice
iDose4 Level 7
0.67 mm slice
IMR Level 3
120 kVp, 125 mAs,
CTDIvol 5.5mGy, DLP: 190.3 mGy×cm, Effective Dose: 2.8 mSv (k=0.015)
* AAPM technical report 96
,
Courtesy of: Fletcher Allen Medical Center
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Abdomen
Standard Reconstruction
IMR
120 kVp, 128 mAs/slice,
CTDIvol 9.4 mGy, DLP 348.74mGy×cm, Effective Dose 5.2mSv (k=0.015)*,
* AAPM technical report 96
Courtesy of Fletcher Allen Medical Center
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Abdomen
Standard Reconstruction
IMR
120 kVp, 128 mAs/slice,
CTDIvol 9.4 mGy, DLP 348.74mGy×cm, Effective Dose 5.2mSv (k=0.015)*,
* AAPM technical report 96
Courtesy of Fletcher Allen Medical Center
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Abdomen
Standard Reconstruction
IMR
80 kVp, 500 mAs/slice,
CTDIvol 16.9 mGy, DLP 380.2 mGy×cm, Effective Dose 5.7 mSv (k=0.015)*,
* AAPM technical report 96
Courtesy of : GD General Hospital
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Chest
Standard Reconstruction
IMR
80 kVp, 10 mAs/slice,
CTDIvol 0.2 mGy, DLP 6.36 mGy×cm, Effective Dose 0.11 mSv (k=0.014)*,
* AAPM technical report 96
Courtesy of: UCL Utrecht
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Brain
Standard Reconstruction
iDose4
IMR
120 kVp, 400 mAs,
CTDIvol 53.6 mGy, DLP 857.6 mGy×cm, Effective Dose 1.8 mSv (k=0.0021)*
* AAPM technical report 96
Courtesy of Carmel Medical Center Israel
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Brain
3mm Standard
Reconstruction
3 mm iDose4 Level 5
1 mm IMR Level 3
120 kVp, 300 mAs,
CTDIvol 14.3 mGy, DLP 866 mGy×cm, Effective Dose 1.8 mSv (k=0.0021)*
* AAPM technical report 96
Courtesy of UCL
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Thoracic Spine
Standard Reconstruction
IMR
120 kVp, 104 mAs/slice,
CTDIvol 6.8 mGy, DLP 234.6 mGy×cm, Effective Dose 3.2mSv (k=0.014)*,
* AAPM technical report 96
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Paper – A phantom study of image quality of 6 iterative
reconstruction algorithms for Brain CT*
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Evaluated “the image quality produced by six different iterative
reconstruction (IR) algorithms in four CT systems in the setting of brain
CT, using different radiation levels and iterative optimisation levels.”1
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The statistical iterative reconstruction products evaluated were:
– iDose4 (Philips); ASiR (GE); SAFIRE (Siemens); AIDR3D
(Toshiba)
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The Model-based iterative reconstruction products evaluated
were:
–
IMR (Philips); Veo (GE)
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Regarding CNR, “Both model-based algorithms clearly improve
spatial resolution. This is particularly remarkable for Philips IMR,
which at the same time greatly reduces noise.”1
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Conclusion: “The four statistical IR algorithms evaluated in the
study all improved the general image quality compared with FBP,
with improvement seen for most or all evaluated quality criteria.
Further improvement was achieved with one of the model-based
IR algorithms.”1 (IMR was that model-based IR algorithm.)
1Six
iterative reconstruction algorithms in brain CT: a phantom study
on image quality at different radiation dose levels.
Askell Löve, MD, et. al.
Skåne University Hospital, Lund University, Lund, Sweden
British Journal of Radiology DOI 10.1259/bjr.20130388
Accepted: 16 September 2013
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