A List-Mode OSEM-Based Attenuation and Scatter Compensation Method for SPECT

Rahman, Ashequr; Laforest, Richard; Jha, Abhinav K.

doi:10.1109/isbi45749.2020.9098333

Cited by 8 publications

(8 citation statements)

References 20 publications

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“…Since these ⍺-emitters have low detectable photons, we suggest that sensitivity is an important study design criterion. More recently, methods that been proposed which use the scatter-window data for the quantification task 49 , which may achieve the goals of both improving sensitivity and accomplishing scatter correction.…”

Section: Discussionmentioning

confidence: 99%

Practical considerations for quantitative clinical SPECT/CT imaging of alpha particle emitting radioisotopes

et al. 2021

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Rationale: Alpha particle emitting radiopharmaceuticals are generating considerable interest for the treatment of disseminated metastatic disease. Molecular imaging of the distribution of these agents is critical to safely and effectively maximize the clinical potential of this emerging drug class. The present studies aim to investigate the feasibility and limitations of quantitative SPECT for 223 Ra, 225 Ac and 227 Th. Methods: Three state-of-the-art SPECT/CT systems were investigated: the GE Discovery NM/CT 670, the GE Optima NM/CT 640, and the Siemens Symbia T6. A series of phantoms, including the NEMA IEC Body phantom, were used to compare and calibrate each camera. Additionally, anthropomorphic physical tumor and vertebrae phantoms were developed and imaged to evaluate the quantitative imaging protocol. Results: This work describes and validates a methodology to calibrate each clinical system. The efficiency of each gamma camera was analyzed and compared. Using the calibration factors obtained with the NEMA phantom, we were able to quantify the activity in 3D-printed tissue phantoms with an error of 2.1%, 3.5% and 11.8% for 223 Ra, 225 Ac, and 227 Th, respectively. Conclusion: The present study validates that quantitative SPECT/CT imaging of 223 Ra, 225 Ac, and 227 Th is achievable but that careful considerations for camera configuration are required. These results will aid in future implementation of SPECT-based patient studies and will help to identify the limiting factors for accurate image-based quantification with alpha particle emitting radionuclides.

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Section: Discussionmentioning

confidence: 99%

Practical considerations for quantitative clinical SPECT/CT imaging of alpha particle emitting radioisotopes

et al. 2021

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“…Another future direction is extending the method to estimate activity uptake directly from list-mode SPECT projections. Recent studies are demonstrating that list-mode data may contain more information than binned projection data [48], [49], and may provide improved quantification [19], [50]- [52]. These studies motivate advancing the proposed method to directly operate on list-mode data.…”

Section: Discussionmentioning

confidence: 97%

A projection-domain low-count quantitative SPECT method for alpha-particle emitting radiopharmaceutical therapy

Li¹,

Benabdallah²,

Abou³

et al. 2021

Preprint

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Quantitative single-photon emission computed tomography (SPECT) provides a mechanism to measure radiation-absorbed doses in lesions and normal organs after administration of alpha-particle emitting radiopharmaceutical therapies (α-RPTs). However, reliable (accurate and precise) quantification of dose requires reliable absolute quantification of regional activity uptake. This is especially challenging for α-RPT due to the complex emission spectra, the very low number of detected counts (up to 20 times lower than those detected in conventional SPECT), the impact of stray-radiation-related noise at these low counts, and other image-degrading processes in SPECT. The conventional reconstruction-based quantification methods are observed to be erroneous for α-RPT SPECT. To address these challenges, we developed a low-count quantitative SPECT (LC-QSPECT) method that incorporates multiple strategies to perform reliable quantification. First, the method directly estimates the regional activity uptake from the projection data, obviating the reconstruction step. Next, the method compensates for radioisotope and SPECT physics, including the isotope spectra, scatter, attenuation, and collimator-detector response, using a Monte Carlo-based approach. The method was validated in the context of three-dimensional SPECT with 223 Ra, a commonly used radionuclide for α-RPT. Validation was performed using both realistic simulation studies, including a virtual clinical trial, as well as synthetic and anthropomorphic physical-phantom studies. Across all studies, the LC-QSPECT method yielded reliable estimates of regional uptake and outperformed conventional ordered subset expectation maximization (OSEM)based reconstruction and geometric transfer matrix (GTM)based partial-volume compensation methods. Besides, the method yielded reliable uptake across different lesion sizes and lesion-to-bone uptake ratios. Further, the method yielded reliable estimates of mean uptake in lesions with varying intra-lesion heterogeneity in uptake. Additionally, the variance of the LC-QSPECT-method-estimated uptake

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“…Previous studies have shown that processing data in list-mode format in SPECT can yield improved performance on clinical tasks compared to processing data in binned format. [49][50][51][52][53] More specifically, it has been quantitatively shown that list-mode data contains more information compared to binned data for the task of estimating attenuation coefficients. 27 Thus, advancing the method to process data in list-mode format directly may lead to even more improved performance.…”

Section: Discussionmentioning

confidence: 99%

Development and task-based evaluation of a scatter-window projection and deep learning-based transmission-less attenuation compensation method for myocardial perfusion SPECT

Yu,

Rahman,

Abbey

et al. 2023

Preprint

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Attenuation compensation (AC) is beneficial for visual interpretation tasks in single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). However, traditional AC methods require the availability of a transmission scan, most often a CT scan. This approach has the disadvantage of increased radiation dose, increased scanner costs, and the possibility of inaccurate diagnosis in cases of misregistration between the SPECT and CT images. Further, many SPECT systems do not include a CT component. To address these issues, we developed a Scatter-window projection and deep Learning-based AC (SLAC) method to perform AC without a separate transmission scan. To investigate the clinical efficacy of this method, we then objectively evaluated the performance of this method on the clinical task of detecting perfusion defects on MPI in a retrospective study with anonymized clinical SPECT/CT stress MPI images. The proposed method was compared with CT-based AC (CTAC) and no-AC (NAC) methods. Our results showed that the SLAC method yielded an almost overlapping receiver operating characteristic (ROC) plot and a similar area under the ROC (AUC) to the CTAC method on this task. These results demonstrate the capability of the SLAC method for transmission-less AC in SPECT and motivate further clinical evaluation.

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A List-Mode OSEM-Based Attenuation and Scatter Compensation Method for SPECT

Cited by 8 publications

References 20 publications

Practical considerations for quantitative clinical SPECT/CT imaging of alpha particle emitting radioisotopes

Practical considerations for quantitative clinical SPECT/CT imaging of alpha particle emitting radioisotopes

A projection-domain low-count quantitative SPECT method for alpha-particle emitting radiopharmaceutical therapy

Development and task-based evaluation of a scatter-window projection and deep learning-based transmission-less attenuation compensation method for myocardial perfusion SPECT

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