Automation of slice thickness measurements in computed tomography images of AAPM CT performance phantom using a non-rotational method

Ximenes, Angelita D; Anam, Khoirul; Hidayanto, Eko; Naufal, Ariij; Rukmana, Dito Andi; Dougherty, Geoff

doi:10.2478/pjmpe-2022-0016

Cited by 3 publications

(3 citation statements)

References 15 publications

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“…One of the weaknesses of the available software is that slice thickness measurement can only be performed for precise positions. If the resulting image is slightly rotated, the resulting measurement is biased [18]. Slice thickness measurement is commonly performed by determining the value of the full-width at half maximum (FWHM) [17], and the difference between automatic measurements and the set slice thickness value has been reported to be less than 0.5 mm for all angles [14].…”

Section: Introductionmentioning

confidence: 99%

Automatic measurement of slice thickness in CT images of a Siemens phantom

Amatullah

Anam

Hidayanto

et al. 2023

Biomed. Phys. Eng. Express

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This study aims to develop a program in Python language for automatic measurement of slice thickness in computed tomography (CT) images of a Siemens phantom with different values of slice thickness, field of view (FOV), and pitch. ASiemens phantom was scanned using a Siemens 64-slice CT scanner with various slice thicknesses (i.e. 2, 4, 6, 8, and 10 mm), FOVs (i.e. 220, 260, and 300 mm), and pitch (i.e. 0.7, 0.9, and 1). Automatic measurement of slice thickness was performed by segmenting the ramp insert in the image and detecting angles of the ramp insert using the Hough transform. The resulting angles were subsequently used to rotate the image. Profiles of pixel along the ramp insert were made from the rotated images,and theslice thickness was calculated by determining the full-width at half maximum (FWHM) of the profiles. The product of the FWHM in pixels and the pixel size was corrected by the tangent of the ramp insert (i.e., 23o) to obtain the measured slice thickness. The results of the automatic measurements were compared with manual measurements carried out using a MicroDicom Viewer. The differences between the automatic and manual measurements at all slice thicknesses were less than 0.30 mm. The automatic and manual measurements had high linear correlations. For variations of the FOV and pitch, the differences between the automatic and manual measurement were less than 0.16 mm. The automatic and manual measurements were not significantly different (p-value > 0.05).

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Section: Introductionmentioning

confidence: 99%

Automatic measurement of slice thickness in CT images of a Siemens phantom

Amatullah

Anam

Hidayanto

et al. 2023

Biomed. Phys. Eng. Express

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“…In radio diagnostic and radiotherapy images, various image quality evaluations and image analysis methods using phantom are effective for image quality improvement and quality control. [5][6][7] The peak signal-to-noise ratio (PSNR) and deformable image registration (DIR) have been used as objective evaluation methods for radiographic imaging and radiotherapy positioning. 8-10 These evaluation methods often use a single analysis method to evaluate positioning errors.…”

Section: Introductionmentioning

confidence: 99%

Objective evaluation method using multiple image analyses for panoramic radiography improvement

Imajo

Tanabe

Nakamura

et al. 2023

Polish Journal of Medical Physics and Engineering

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Introduction In the standardization of panoramic radiography quality, the education and training of beginners on panoramic radiographic imaging are important. We evaluated the relationship between positioning error factors and multiple image analysis results for reproducible panoramic radiography. Material and methods Using a panoramic radiography system and a dental phantom, reference images were acquired on the Frankfurt plane along the horizontal direction, midsagittal plane along the left–right direction, and for the canine on the forward–backward plane. Images with positioning errors were acquired with 1–5 mm shifts along the forward– backward direction and 2–10° rotations along the horizontal (chin tipped high/low) and vertical (left–right side tilt) directions on the Frankfurt plane. The cross-correlation coefficient and angle difference of the occlusion congruent plane profile between the reference and positioning error images, peak signal-to-noise ratio (PSNR), and deformation vector value by deformable image registration were compared and evaluated. Results The cross-correlation coefficients of the occlusal plane profiles showed the greatest change in the chin tipped high images and became negatively correlated from 6° image rotation (r = −0.29). The angle difference tended to shift substantially with increasing positioning error, with an angle difference of 8.9° for the 10° chin tipped low image. The PSNR was above 30 dB only for images with a 1-mm backward shift. The positioning error owing to the vertical rotation was the largest for the deformation vector value. Conclusions Multiple image analyses allow to determine factors contributing to positioning errors in panoramic radiography and may enable error correction. This study based on phantom imaging can support the education of beginners regarding panoramic radiography.

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“…The algorithm was evaluated by Lasiyah et al [18] for variations of filter and distance from the isocenter, and evaluated by Widyanti et al [19] for variation of noise. The algorithm was also refined by Ximenes et al [20]. However, the previous automated SSP measurement was only implemented at one field of view (FOV).…”

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An evaluation of automated measurement of slice sensitivity profile of computed tomography image: field of view variations

Widyanti

Anam²,

Hidayanto³

et al. 2023

IJEECS

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This study aims to evaluate the automated measurement of slice sensitivity profile (SSP) on the American Association of Physicists in Medicine (AAPM) computed tomography (CT) performance phantom for variations of slice thickness and field of view (FOV). The AAPM CT performance phantom was scanned using a Philips MRC 880 CT Scanner for variations of slice thickness and FOV. The slice thickness values were 1, 3, and 5 mm. The FOV values were 240, 300, 340, 400, and 440 mm. The automated SSPs and their fullwidth at half maximums (FWHMs) were automatically measured from the middle stair object of the phantom. To validate the automated measurement results, the FWHM values of SSPs obtained were compared to those from manual measurements. The differences between FWHMs from automated measurements and set slice thicknesses are less than 0.3 mm, while the differences between FWHMs from automated and manual measurements are less than 0.2 mm. The results from automated measurements are closer to the set slice thickness than those from manual measurements. This automated SSP measurement provides high accuracy and precision for both the slice thickness and the FOV variations.

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Automation of slice thickness measurements in computed tomography images of AAPM CT performance phantom using a non-rotational method

Cited by 3 publications

References 15 publications

Automatic measurement of slice thickness in CT images of a Siemens phantom

Automatic measurement of slice thickness in CT images of a Siemens phantom

Objective evaluation method using multiple image analyses for panoramic radiography improvement

An evaluation of automated measurement of slice sensitivity profile of computed tomography image: field of view variations

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