X-ray-based attenuation correction for positron emission tomography/computed tomography scanners

Kinahan, Paul E.; Hasegawa, B.H.; Beyer, Thomas

doi:10.1053/snuc.2003.127307

Cited by 455 publications

(315 citation statements)

References 26 publications

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“…For instance, whiskers of lung tissues for segmentation methods are longer compared to other regions and reflect the dispersion of lung tissue estimates. As far as segmentation-based attenuation correction is concerned, the lung is one of the most challenging organs [8] given that it has been shown that the density of lung tissue is considerably different from subject to subject, depends on breathing patterns and varies by as much as 30% with age and in the presence of pulmonary disease [28]. The correlation coefficient resulting from the ROI-based analysis comparing PET images corrected for attenuation using different energy-mapping methods and the PET image corrected using the µ-map generated by the software supplied by the manufacturer are summarized in Table 3.…”

Section: Clinical Studiesmentioning

confidence: 99%

“…In stand-alone PET systems, attenuation correction is usually performed using either rod positron-emitting ( 68 Ga/ 68 Ge) or point single-photon emitting ( 137 Cs) sources orbiting around the patient [8]. Since the energy of photons emitted from positron-emitting rod sources is the same and the γ-rays emitted by 137 Cs (662 keV) are very close to the energy of annihilation photons in PET (511 keV), transmission scanning-based attenuation correction is the method of choice for stand-alone PET scanners.…”

Section: Introductionmentioning

confidence: 99%

“…These include scaling [17], segmentation [8], hybrid (segmentation/scaling) [9], bilinear calibration curve [16,18], dual-energy decomposition methods [19,20], and quadratic polynomial calibration mapping [21]. The latter was recently proposed by our group and assessed using clinical studies.…”

Section: Introductionmentioning

confidence: 99%

“…Each of the above-referenced energymapping techniques has advantages and drawbacks and, to the best of our knowledge, a comprehensive comparative assessment of these methods has not been performed yet in a clinical setting. Published reports to date compared only two or at most three methods [8,9,17]. In our previous study, we reported on the comparative assessment of a number of energy-mapping methods using a small sample of clinical datasets where the evaluation was limited to the generated µ-maps only without assessing the impact on the resulting PET images [22].…”

Section: Introductionmentioning

confidence: 99%

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Comparative Assessment of Energy-Mapping Approaches in CT-Based Attenuation Correction for PET

Shirmohammad

Sarkar

et al. 2010

Mol Imaging Biol

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Introduction: Reliable quantification in positron emission tomography (PET) requires accurate attenuation correction of emission data, which in turn entails accurate determination of the attenuation map (µ-map) of the object under study. One of the main steps involved in CTbased attenuation correction (CTAC) is energy-mapping, or the conversion of linear attenuation coefficients (µ) calculated at the effective CT energy to those corresponding to 511 keV. Materials and methods: The aim of this study is to compare different energy-mapping techniques including scaling, segmentation, the hybrid method, the bilinear calibration curve technique and the dual-energy approach to generate the µ-maps required for attenuation correction. In addition, our newly proposed method involving a quadratic polynomial calibration curve was also assessed. The µ-maps generated for both phantom and clinical studies were assessed qualitatively and quantitatively. A cylindrical polyethylene phantom containing different concentrations of K 2 HPO 4 in water was scanned and the µ-maps calculated from the corresponding CT images using the above-referenced energy-mapping methods. The CT images of five whole-body data sets acquired on a GE Discovery LS PET/ CT scanner were employed to generate µ-maps using different energy-mapping approaches that were compared with the µ-maps generated at 511 keV using 68 Ge/ 68 Ga rod sources. In another experiment, the evaluation was performed on PET images of a clinical study corrected for attenuation using µ-maps generated using the above described methods. The evaluation was performed for three different tissue types, namely, soft tissue, lung, and bone. Results and Discussion: All energy-mapping methods yielded almost similar results for soft tissues. The mean relative differences between scaling, segmentation, hybrid, bilinear, and quadratic polynomial calibration curve methods and the transmission scan serving as reference were 6.60%, 6.56%, 6.60%, 5.96%, and 7.36%, respectively. However, the scaling method produced the largest difference (16%) for bone tissues. For lung tissues, the segmentation method produced the largest difference (14.9%). The results for reconstructed PET imagesCorrespondence to: Mohammad R. Ay; e-mail: mohammadreza_ay@tums.ac.ir followed a similar trend. For soft tissues, all energy-mapping methods yield results in nearly the same range. However, in bone tissues, the scaling method resulted in considerable bias in the µ-maps and the reconstructed PET images. The segmentation method also produced noticeable bias especially in regions with variable densities such as the lung, since a single µ is assigned to the lungs. Apart from the aforementioned case, despite small differences in the generated µ-maps, the use of different energy-mapping methods does not affect, to a visible or measurable extent, the reconstructed PET images.

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Section: Clinical Studiesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comparative Assessment of Energy-Mapping Approaches in CT-Based Attenuation Correction for PET

Shirmohammad

Sarkar

et al. 2010

Mol Imaging Biol

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“…However, the use of CT images for attenuation correction of PET data is known to produce artifacts in the resulting PET images in some cases. 29,30 This includes artifacts resulting from the polychromaticity of x-ray photons and resulting beam hardening, misregistration between emission and transmission data, the use of contrast-enhanced CT, truncation resulting from the limited field-of-view of CT, the presence of metallic objects, and artifacts arising from x-ray scatter in CT images. 31 Application of PET/CT in nuclear medicine or radiology is a detection and quantitation task based on standardized uptake value (SUV).…”

Section: Introductionmentioning

confidence: 99%

Attenuation Correction Strategies for Positron Emission Tomography/Computed Tomography and 4-Dimensional Positron Emission Tomography/Computed Tomography

Pan

Zaidi

2013

PET Clinics

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Positron Emission Tomography

Bacharach¹

2006

Cardiac CT, PET and MR

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X-ray-based attenuation correction for positron emission tomography/computed tomography scanners

Cited by 455 publications

References 26 publications

Comparative Assessment of Energy-Mapping Approaches in CT-Based Attenuation Correction for PET

Comparative Assessment of Energy-Mapping Approaches in CT-Based Attenuation Correction for PET

Attenuation Correction Strategies for Positron Emission Tomography/Computed Tomography and 4-Dimensional Positron Emission Tomography/Computed Tomography

Positron Emission Tomography

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