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742 results on '"Dehdashti, Farrokh"'

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

Author

Li, Zekun, Benabdallah, Nadia, Abou, Diane S., Baumann, Brian C., Dehdashti, Farrokh, Ballard, David H., Liu, Jonathan, Jammalamadaka, Uday, Laforest, Richard, Wahl, Richard L., Thorek, Daniel L. J., and Jha, Abhinav K.

Subjects
Physics - Medical Physics
Abstract

Single-photon emission computed tomography (SPECT) provides a mechanism to estimate regional isotope uptake in lesions and at-risk organs after administration of {\alpha}-particle-emitting radiopharmaceutical therapies ({\alpha}-RPTs). However, this estimation task is challenging due to the complex emission spectra, the very low number of detected counts, the impact of stray-radiation-related noise at these low counts, and the multiple image-degrading processes in SPECT. The conventional reconstruction-based quantification methods are observed to be erroneous for {\alpha}-RPT SPECT. To address these challenges, we developed a low-count quantitative SPECT (LC-QSPECT) method that directly estimates the regional activity uptake from the projection data, compensates for stray-radiation-related noise, and for the radioisotope and SPECT physics. The method was validated in the context of three-dimensional SPECT with 223 Ra. Validation was performed using both realistic simulation studies, including a virtual clinical trial, and synthetic and anthropomorphic physical-phantom studies. Across all studies, the LC-QSPECT method yielded reliable regional-uptake estimates and outperformed the conventional ordered subset expectation maximization (OSEM)-based reconstruction and geometric transfer matrix (GTM)-based post-reconstruction partial-volume compensation methods. Further, the method yielded reliable uptake across different lesion sizes, contrasts, and different levels of intra-lesion heterogeneity. Additionally, the variance of the estimated uptake approached the Cram\'e-Rao bound-defined theoretical limit.

Published
2021

3. Observer study-based evaluation of a stochastic and physics-based method to generate oncological PET images

Author

Liu, Ziping, Laforest, Richard, Mhlanga, Joyce, Fraum, Tyler J., Itani, Malak, Dehdashti, Farrokh, Siegel, Barry A., and Jha, Abhinav K.

Subjects
Physics - Medical Physics, Electrical Engineering and Systems Science - Image and Video Processing
Abstract

Objective evaluation of new and improved methods for PET imaging requires access to images with ground truth, as can be obtained through simulation studies. However, for these studies to be clinically relevant, it is important that the simulated images are clinically realistic. In this study, we develop a stochastic and physics-based method to generate realistic oncological two-dimensional (2-D) PET images, where the ground-truth tumor properties are known. The developed method extends upon a previously proposed approach. The approach captures the observed variabilities in tumor properties from actual patient population. Further, we extend that approach to model intra-tumor heterogeneity using a lumpy object model. To quantitatively evaluate the clinical realism of the simulated images, we conducted a human-observer study. This was a two-alternative forced-choice (2AFC) study with trained readers (five PET physicians and one PET physicist). Our results showed that the readers had an average of ~ 50% accuracy in the 2AFC study. Further, the developed simulation method was able to generate wide varieties of clinically observed tumor types. These results provide evidence for the application of this method to 2-D PET imaging applications, and motivate development of this method to generate 3-D PET images.

Published
2021

7. #27. First-in-human evaluation of safety and dosimetry of 64Cu-LLP2A for PET imaging

Author

Laforest, Richard, primary, Ghai, Anchal, additional, Fraum, Tyler J., additional, Oyama, Reiko, additional, Frye, Jennifer, additional, Kaemmerer, Helen, additional, Gaehle, Greg, additional, Voller, Tom, additional, Mpoy, Cedric, additional, Rogers, Buck E., additional, Fiala, Mark, additional, Shoghi, Kooresh I., additional, Achilefu, Samuel, additional, Rettig, Michael, additional, Vij, Ravi, additional, DiPersio, John F., additional, Schwarz, Sally, additional, Shokeen, Monica, additional, and Dehdashti, Farrokh, additional

Published
2024
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8. Spatial relationship of 2-deoxy-2-[18F]-fluoro-D-glucose positron emission tomography and magnetic resonance diffusion imaging metrics in cervical cancer

Author

Floberg, John M, Fowler, Kathryn J, Fuser, Dominique, DeWees, Todd A, Dehdashti, Farrokh, Siegel, Barry A, Wahl, Richard L, Schwarz, Julie K, and Grigsby, Perry W

Subjects
Biomedical and Clinical Sciences, Clinical Sciences, Oncology and Carcinogenesis, Biomedical Imaging, Cancer, Clinical Research, Rare Diseases, Detection, screening and diagnosis, 4.1 Discovery and preclinical testing of markers and technologies, PET/MRI, Multimodal imaging, Diffusion imaging, Cervical cancer, Imaging biomarkers, Medical Biochemistry and Metabolomics, Clinical sciences, Oncology and carcinogenesis
Abstract

BackgroundThis study investigated the spatial relationship of 2-deoxy-2-[18F]-fluoro-D-glucose positron emission tomography ([18F]FDG-PET) standardized uptake values (SUVs) and apparent diffusion coefficients (ADCs) derived from magnetic resonance (MR) diffusion imaging on a voxel level using simultaneously acquired PET/MR data. We performed an institutional retrospective analysis of patients with newly diagnosed cervical cancer who received a pre-treatment simultaneously acquired [18F]FDG-PET/MR. Voxel SUV and ADC values, and global tumor metrics including maximum SUV (SUVmax), mean ADC (ADCmean), and mean tumor-to-muscle ADC ratio (ADCT/M) were compared. The impacts of histology, grade, and tumor volume on the voxel SUV to ADC relationship were also evaluated. The potential prognostic value of the voxel SUV/ADC relationship was evaluated in an exploratory analysis using Kaplan-Meier/log-rank and univariate Cox analysis.ResultsSeventeen patients with PET/MR scans were identified. There was a significant inverse correlation between SUVmax and ADCmean, and SUVmax and ADCT/M. In the voxelwise analysis, squamous cell carcinomas (SCCAs) and poorly differentiated tumors showed a consistent significant inverse correlation between voxel SUV and ADC values; adenocarcinomas (AdenoCAs) and well/moderately differentiated tumors did not. The strength of the voxel SUV/ADC correlation varied with metabolic tumor volume (MTV). On log-rank analysis, the correlation between voxel SUV/ADC values was prognostic of disease-free survival (DFS).ConclusionsIn this hypothesis-generating study, a consistent inverse correlation between voxel SUV and ADC values was seen in SCCAs and poorly differentiated tumors. On univariate statistical analysis, correlation between voxel SUV and ADC values was prognostic for DFS.

Published
2018

15. Summary: SNMMI Procedure Standard/EANM Practice Guideline for Estrogen Receptor Imaging of Patients with Breast Cancer Using 16α-[18F]Fluoro-17β-Estradiol PET

Author

Mankoff, David, primary, Balogová, Soňa, additional, Dunnwald, Lisa, additional, Dehdashti, Farrokh, additional, DeVries, Erik, additional, Evangelista, Laura, additional, Van Krutchen, Michel, additional, Vaz, Sofia Carrilho, additional, Fowler, Amy, additional, Linden, Hannah, additional, and Ulaner, Gary A., additional

Published
2023
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16. Chemokine Receptor 2 Targeted PET/CT Imaging Distant Metastases in Pancreatic Ductal Adenocarcinoma

Author

Zhang, Xiaohui, primary, Detering, Lisa, additional, Heo, Gyu Seong, additional, Sultan, Deborah, additional, Luehmann, Hannah, additional, Li, Lin, additional, Somani, Vikas, additional, Lesser, Josie, additional, Tao, Joan, additional, Kang, Liang-I., additional, Li, Alexandria, additional, Lahad, Divangana, additional, Rho, Shinji, additional, Ruzinova, Marianna B., additional, DeNardo, David G., additional, Dehdashti, Farrokh, additional, Lim, Kian-Huat, additional, and Liu, Yongjian, additional

Published
2023
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25. Appropriate Use Criteria for Estrogen Receptor-Targeted PET Imaging with 16α-18F-Fluoro-17β-Fluoroestradiol

Author

Ulaner, Gary A, Mankoff, David A, Clark, Amy S, Fowler, Amy M, Linden, Hannah M, Peterson, Lanell M, Dehdashti, Farrokh, Kurland, Brenda F, Mortimer, Joanne, Mouabbi, Jason, Moon, Dae Hyuk, de Vries, Elisabeth G E, and Guided Treatment in Optimal Selected Cancer Patients (GUTS)

Subjects
Breast Neoplasms/diagnostic imaging, Estradiol/metabolism, Receptors, Estrogen, Biopsy, Positron-Emission Tomography, Receptors, Humans, Radiology, Nuclear Medicine and imaging, Female, Estrogen, United States, Molecular Imaging
Abstract

PET imaging with 16α- 18F-fluoro-17β-fluoroestradiol ( 18F-FES), a radiolabeled form of estradiol, allows whole-body, noninvasive evaluation of estrogen receptor (ER). 18F-FES is approved by the U.S. Food and Drug Administration as a diagnostic agent "for the detection of ER-positive lesions as an adjunct to biopsy in patients with recurrent or metastatic breast cancer." The Society of Nuclear Medicine and Molecular Imaging (SNMMI) convened an expert work group to comprehensively review the published literature for 18F-FES PET in patients with ER-positive breast cancer and to establish appropriate use criteria (AUC). The findings and discussions of the SNMMI 18F-FES work group, including example clinical scenarios, were published in full in 2022 and are available at https://www.snmmi.org/auc Of the clinical scenarios evaluated, the work group concluded that the most appropriate uses of 18F-FES PET are to assess ER functionality when endocrine therapy is considered either at initial diagnosis of metastatic breast cancer or after progression of disease on endocrine therapy, the ER status of lesions that are difficult or dangerous to biopsy, and the ER status of lesions when other tests are inconclusive. These AUC are intended to enable appropriate clinical use of 18F-FES PET, more efficient approval of FES use by payers, and promotion of investigation into areas requiring further research. This summary includes the rationale, methodology, and main findings of the work group and refers the reader to the complete AUC document.

Published
2023

27. Positron Emission Tomography with [18F]-3′-Deoxy-3′fluorothymidine (FLT) as a Predictor of Outcome in Patients with Locally Advanced Resectable Rectal Cancer: a Pilot Study

Author

Dehdashti, Farrokh, Grigsby, Perry W, Myerson, Robert J, Nalbantoglu, ILKe, Ma, Changqing, and Siegel, Barry A

Subjects
Biomedical and Clinical Sciences, Clinical Sciences, Oncology and Carcinogenesis, Biomedical Imaging, Cancer, Clinical Research, Rare Diseases, Adult, Aged, Chemoradiotherapy, Adjuvant, Dideoxynucleosides, Female, Humans, Kaplan-Meier Estimate, Male, Middle Aged, Neoadjuvant Therapy, Pilot Projects, Positron-Emission Tomography, Predictive Value of Tests, Prognosis, Rectal Neoplasms, Treatment Outcome, Physiology, Nuclear Medicine & Medical Imaging, Clinical sciences
Abstract

PurposeThis pilot study was performed to evaluate whether tumor uptake of (18)F-labeled 3'-deoxy-3'fluorothymidine (FLT), a proliferative radiotracer, at baseline and early during therapy, is predictive of outcome in locally advanced rectal cancer.ProceduresFourteen patients underwent positron emission tomography (PET) with 2-deoxy-2-[(18)F]fluoro-D-glucose (FDG) and FLT before therapy and PET with FLT approximately 2 weeks after initiating neoadjuvant chemoradiotherapy. FLT and FDG uptake were evaluated qualitatively and by maximum standardized uptake value (SUV(max)). Tumor FLT and FDG uptake were correlated with disease-free survival (DFS).ResultsThirteen patients underwent surgery after therapy, one died before surgery with progressive disease. FDG-PET/computed tomography detected regional lymph node metastases in five and FLT-PET was positive in one. High pretherapy FDG uptake (SUV(max) ≥ 14.3), low during-therapy FLT uptake (SUV(max)

Published
2013

36. Supplementary Figure 2S from Standardized Uptake Value for 18F-Fluorodeoxyglucose Is a Marker of Inflammatory State and Immune Infiltrate in Cervical Cancer

Author

Floberg, John M., primary, Zhang, Jin, primary, Muhammad, Naoshad, primary, DeWees, Todd A., primary, Inkman, Matthew, primary, Chen, Kevin, primary, Lin, Alexander J., primary, Rashmi, Ramachandran, primary, Jayachandran, Kay, primary, Edelson, Brian T., primary, Siegel, Barry A., primary, Dehdashti, Farrokh, primary, Grigsby, Perry W., primary, Markovina, Stephanie, primary, and Schwarz, Julie K., primary

Published
2023
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37. Supplementary Figure 1S from Standardized Uptake Value for 18F-Fluorodeoxyglucose Is a Marker of Inflammatory State and Immune Infiltrate in Cervical Cancer

Author

Floberg, John M., primary, Zhang, Jin, primary, Muhammad, Naoshad, primary, DeWees, Todd A., primary, Inkman, Matthew, primary, Chen, Kevin, primary, Lin, Alexander J., primary, Rashmi, Ramachandran, primary, Jayachandran, Kay, primary, Edelson, Brian T., primary, Siegel, Barry A., primary, Dehdashti, Farrokh, primary, Grigsby, Perry W., primary, Markovina, Stephanie, primary, and Schwarz, Julie K., primary

Published
2023
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38. Supplementary Figure 4S from Standardized Uptake Value for 18F-Fluorodeoxyglucose Is a Marker of Inflammatory State and Immune Infiltrate in Cervical Cancer

Author

Floberg, John M., primary, Zhang, Jin, primary, Muhammad, Naoshad, primary, DeWees, Todd A., primary, Inkman, Matthew, primary, Chen, Kevin, primary, Lin, Alexander J., primary, Rashmi, Ramachandran, primary, Jayachandran, Kay, primary, Edelson, Brian T., primary, Siegel, Barry A., primary, Dehdashti, Farrokh, primary, Grigsby, Perry W., primary, Markovina, Stephanie, primary, and Schwarz, Julie K., primary

Published
2023
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39. Supplementary Figure 3S from Standardized Uptake Value for 18F-Fluorodeoxyglucose Is a Marker of Inflammatory State and Immune Infiltrate in Cervical Cancer

Author

Floberg, John M., primary, Zhang, Jin, primary, Muhammad, Naoshad, primary, DeWees, Todd A., primary, Inkman, Matthew, primary, Chen, Kevin, primary, Lin, Alexander J., primary, Rashmi, Ramachandran, primary, Jayachandran, Kay, primary, Edelson, Brian T., primary, Siegel, Barry A., primary, Dehdashti, Farrokh, primary, Grigsby, Perry W., primary, Markovina, Stephanie, primary, and Schwarz, Julie K., primary

Published
2023
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41. Summary: Appropriate Use Criteria for Estrogen Receptor–Targeted PET Imaging with 16α-18F-Fluoro-17β-Fluoroestradiol

Author

Ulaner, Gary A., primary, Mankoff, David A., additional, Clark, Amy S., additional, Fowler, Amy M., additional, Linden, Hannah M., additional, Peterson, Lanell M., additional, Dehdashti, Farrokh, additional, Kurland, Brenda F., additional, Mortimer, Joanne, additional, Mouabbi, Jason, additional, Moon, Dae Hyuk, additional, and de Vries, Elisabeth G.E., additional

Published
2023
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43. A Projection-Domain Low-Count Quantitative SPECT Method for ɑ-Particle-Emitting Radiopharmaceutical Therapy

Author

Li, Zekun, primary, Benabdallah, Nadia, additional, Abou, Diane S., additional, Baumann, Brian C., additional, Dehdashti, Farrokh, additional, Ballard, David H., additional, Liu, Jonathan, additional, Jammalamadaka, Uday, additional, Laforest, Richard L., additional, Wahl, Richard L, additional, Thorek, Daniel L. J., additional, and Jha, Abhinav K., additional

Published
2023
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