Development of a Novel Body Phantom with Bone Equivalent Density for Evaluation of Bone SPECT

Ichikawa, Hajime; Miwa, Koichi; Matsutomo, Norikazu; Watanabe, Yoichi; Kato, Takefumi; Shimada, Hideki

doi:10.6009/jjrt.2015_jsrt_71.12.1235

Cited by 13 publications

(11 citation statements)

References 22 publications

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“…The activity concentration and linear attenuation coefficient (cm −1 ) can be modified in three different locations of soft tissue, normal spine, and simulated tumor in bone using our custom-designed phantom. Thus, the effects of scatter and attenuation of photons by bone for 18 F-NaF PET/CT imaging can be investigated [19].…”

Section: Discussionmentioning

confidence: 99%

Optimization of a Bayesian penalized likelihood algorithm (Q.Clear) for 18F-NaF bone PET/CT images acquired over shorter durations using a custom-designed phantom

et al. 2020

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Background The Bayesian penalized likelihood (BPL) algorithm Q.Clear (GE Healthcare) allows fully convergent iterative reconstruction that results in better image quality and quantitative accuracy, while limiting image noise. The present study aimed to optimize BPL reconstruction parameters for 18F-NaF PET/CT images and to determine the feasibility of 18F-NaF PET/CT image acquisition over shorter durations in clinical practice. Methods A custom-designed thoracic spine phantom consisting of several inserts, soft tissue, normal spine, and metastatic bone tumor, was scanned using a Discovery MI PET/CT scanner (GE Healthcare). The phantom allows optional adjustment of activity distribution, tumor size, and attenuation. We reconstructed PET images using OSEM + PSF + TOF (2 iterations, 17 subsets, and a 4-mm Gaussian filter), BPL + TOF (β = 200 to 700), and scan durations of 30–120 s. Signal-to-noise ratios (SNR), contrast, and coefficients of variance (CV) as image quality indicators were calculated, whereas the quantitative measures were recovery coefficients (RC) and RC linearity over a range of activity. We retrospectively analyzed images from five persons without bone metastases (male, n = 1; female, n = 4), then standardized uptake values (SUV), CV, and SNR at the 4th, 5th, and 6th thoracic vertebra were calculated in BPL + TOF (β = 400) images. Results The optimal reconstruction parameter of the BPL was β = 400 when images were acquired at 120 s/bed. At 90 s/bed, the BPL with a β value of 400 yielded 24% and 18% higher SNR and contrast, respectively, than OSEM (2 iterations; 120 s acquisitions). The BPL was superior to OSEM in terms of RC and the RC linearity over a range of activity, regardless of scan duration. The SUVmax were lower in BPL, than in OSEM. The CV and vertebral SNR in BPL were superior to those in OSEM. Conclusions The optimal reconstruction parameters of 18F-NaF PET/CT images acquired over different durations were determined. The BPL can reduce PET acquisition to 90 s/bed in 18F-NaF PET/CT imaging. Our results suggest that BPL (β = 400) on SiPM-based TOF PET/CT scanner maintained high image quality and quantitative accuracy even for shorter acquisition durations.

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Section: Discussionmentioning

confidence: 99%

Optimization of a Bayesian penalized likelihood algorithm (Q.Clear) for 18F-NaF bone PET/CT images acquired over shorter durations using a custom-designed phantom

et al. 2020

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“…1). This phantom can be used to generate SPECT images of bone metastasis with a realistic abdomen contour [34]. The phantom contains a 99m Tc solution to simulate soft tissue, the vertebral body, spinous and transverse process, and tumor region contained a bone-equivalent solution of K 2 HPO 4 and 99m Tc [35].…”

Section: Phantom Studies Phantom Designmentioning

confidence: 99%

Phantom and clinical evaluation of bone SPECT/CT image reconstruction with xSPECT algorithm

et al. 2020

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Background: Two novel methods of image reconstruction, xSPECT Quant (xQ) and xSPECT Bone (xB), that use an ordered subset conjugate gradient minimizer (OSCGM) for SPECT/CT reconstruction have been proposed. The present study compares the performance characteristics of xQ, xB, and conventional Flash3D (F3D) reconstruction using images derived from phantoms and patients. Methods: A custom-designed body phantom for bone SPECT was scanned using a Symbia Intevo (Siemens Healthineers), and reconstructed xSPECT images were evaluated. The phantom experiments proceeded twice with different activity concentrations and sphere sizes. A phantom with 28-mm spheres containing a 99m Tc-background and tumor-to-normal bone ratios (TBR) of 1, 2, 4, and 10 were generated, and convergence property against various TBR was evaluated across 96 iterations. A phantom with four spheres (13-, 17-, 22-, and 28-mm diameters), containing a 99m Tc-background at TBR4, was also generated. The full width at half maximum of an imaged spinous process (10 mm), coefficients of variance (CV), contrast-to-noise ratio (CNR), and recovery coefficients (RC) were evaluated after reconstructing images of a spine using Flash 3D (F3D), xQ, and xB. We retrospectively analyzed images from 20 patients with suspected bone metastases (male, n = 13) which were acquired using [ 99m Tc]Tc-(H)MDP SPECT/CT, then CV and standardized uptake values (SUV) at the 4 th vertebral body (L4) were compared after xQ and xB reconstruction in a clinical setup. Results: Mean activity concentrations with various TBR converged according to increasing numbers of iterations. The spatial resolution of xB was considerably superior to xQ and F3D, and it approached almost the actual size regardless of the iteration numbers during reconstruction. The CV and RC were better for xQ and xB than for F3D. The CNR peaked at 24 iterations for xQ and 48 iterations for F3D and xB, respectively. The RC between xQ and xB significantly differed at lower numbers of iterations but were almost equivalent at higher numbers of iterations. The reconstructed xQ and xB images of the clinical patients showed a significant difference in the SUV max and SUV peak .

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“…We custom-designed a physical three-dimensional phantom to determine the bone SPECTspecific distribution of activity and the linear attenuation coefficient (Figure 1). This phantom can be used to generate SPECT images of bone metastasis with a realistic abdomen contour [34]. The phantom contains a 99m Tc solution to simulate the soft tissue, and the vertebral body, spinous and transverse process and tumor region contained a bone-equivalent solution of K 2 HPO 4 and 99m Tc [35].…”

Section: Phantom Designmentioning

confidence: 99%

Phantom and clinical evaluation of bone SPECT/CT image reconstruction with xSPECT algorithm

Miyaji

Miwa

Tokiwa

et al. 2020

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Abstract Background Two novel methods of image reconstruction, xSPECT Quant (xQ) and xSPECT Bone (xB) that use an ordered subset conjugate gradient minimizer (OSCGM) for bone SPECT/CT have been proposed. The present study compares the performance characteristics of xQ, xB and conventional Flash3D (F3D) reconstruction using images derived from phantoms and patients. Methods A custom-designed body phantom for bone SPECT was scanned using a Symbia Intevo (Siemens Healthineers) and reconstructed xSPECT images were evaluated. The phantom experiments proceeded twice in different activity concentrations and sphere sizes. A phantom with 28-mm spheres containing a 99mTc background and having tumor-to-normal bone ratios (TBR) of 1, 2, 4 and 10, were generated and its convergence property was evaluated across 96 iterations. A phantom with four spheres (13-, 17-, 22-, and 28-mm diameters), containing a 99mTc-background at TBR4, was also generated. The full width at half maximum of an imaged spinous process (10 mm), coefficients of variance (CV), contrast-to-noise ratio (CNR) and recovery coefficients (RC) of an imaged spine were evaluated with F3D, xQ and xB.Images from 20 patients with suspected bone metastases (male, n = 13) were acquired using 99mTc-(H)MDP SPECT/CT, then the CV and standardized uptake value (SUV) at the 4th vertebral body (L4) were compared with xQ and xB in a clinical setup. Results Mean activity concentrations with various TBR converged accordance to increasing numbers of iterations. Spatial resolution was improved in the order of xB, xQ and F3D regardless of the number of iterations during reconstruction. The CV and RC were better for xQ and xB than for F3D. The CNR peaked at 24 iterations for xQ and 48 iterations for F3D and xB, respectively. The RC significantly differed between xQ and xB at lower numbers of iterations, whereas those of xQ and xB became almost equivalent at higher numbers of iterations. Significant differences in the clinical patients’ SUVmax and SUVpeak were observed in the reconstructed xQ and xB images. Conclusions The reconstructed xQ and xB images were more accurate than those conventionally reconstructed using F3D. Bone SPECT xB imaging offered essentially unchanged spatial resolution even when the numbers of iterations did not converge. The xB further enhanced SPECT image quality using CT data. Our findings provide important evidence for understanding the performance characteristics of the novel xQ and xB algorithms.

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Development of a Novel Body Phantom with Bone Equivalent Density for Evaluation of Bone SPECT

Cited by 13 publications

References 22 publications

Optimization of a Bayesian penalized likelihood algorithm (Q.Clear) for 18F-NaF bone PET/CT images acquired over shorter durations using a custom-designed phantom

Optimization of a Bayesian penalized likelihood algorithm (Q.Clear) for 18F-NaF bone PET/CT images acquired over shorter durations using a custom-designed phantom

Phantom and clinical evaluation of bone SPECT/CT image reconstruction with xSPECT algorithm

Phantom and clinical evaluation of bone SPECT/CT image reconstruction with xSPECT algorithm

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