scholarly journals Impact of the Noise Penalty Factor on Quantification in Bayesian Penalized Likelihood (Q.Clear) Reconstructions of 68Ga-PSMA PET/CT Scans

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 847
Author(s):  
Sjoerd Rijnsdorp ◽  
Mark J. Roef ◽  
Albert J. Arends
Keyword(s):  
Penalized Likelihood ◽  
Ct Scans ◽  
Ct Scanner ◽  
Scan Time ◽  
Standardized Uptake Values ◽  
Positron Emission ◽  
Penalty Factor ◽  
Psma Pet ◽  
Pet Ct ◽  
Voxel Grid

Functional imaging with 68Ga prostate-specific membrane antigen (PSMA) and positron emission tomography (PET) can fulfill an important role in treatment selection and adjustment in prostate cancer. This article focusses on quantitative assessment of 68Ga-PSMA-PET. The effect of various parameters on standardized uptake values (SUVs) is explored, and an optimal Bayesian penalized likelihood (BPL) reconstruction is suggested. PET acquisitions of two phantoms consisting of a background compartment and spheres with diameter 4 mm to 37 mm, both filled with solutions of 68Ga in water, were performed with a GE Discovery 710 PET/CT scanner. Recovery coefficients (RCs) in multiple reconstructions with varying noise penalty factors and acquisition times were determined and analyzed. Apparent recovery coefficients of spheres with a diameter smaller than 17 mm were significantly lower than those of spheres with a diameter of 17 mm and bigger (p < 0.001) for a tumor-to-background (T/B) ratio of 10:1 and a scan time of 10 min per bed position. With a T/B ratio of 10:1, the four largest spheres exhibit significantly higher RCs than those with a T/B ratio of 20:1 (p < 0.0001). For spheres with a diameter of 8 mm and less, alignment with the voxel grid potentially affects the RC. Evaluation of PET/CT scans using (semi-)quantitative measures such as SUVs should be performed with great caution, as SUVs are influenced by scanning and reconstruction parameters. Based on the evaluation of multiple reconstructions with different β of phantom scans, an intermediate β (600) is suggested as the optimal value for the reconstruction of clinical 68Ga-PSMA PET/CT scans, considering that both detectability and reproducibility are relevant.

scholarly journals Changing Threshold-Based Segmentation Has No Relevant Impact on Semi-Quantification in the Context of Structured Reporting for PSMA-PET/CT

Cancers ◽  
2022 ◽  
Vol 14 (2) ◽  
pp. 270
Author(s):  
Patrick W. Mihatsch ◽  
Matthias Beissert ◽  
Martin G. Pomper ◽  
Thorsten A. Bley ◽  
Anna K. Seitz ◽  
...  
Keyword(s):  
Tumor Volume ◽  
Bone Lesions ◽  
Primary Staging ◽  
Standardized Uptake Values ◽  
Positron Emission ◽  
Diagnostic Certainty ◽  
Psma Pet ◽  
Pet Ct ◽  
The Stability ◽  
Specific Membrane

Prostate-specific membrane antigen (PSMA)-directed positron emission tomography/computed tomography (PET/CT) is increasingly utilized for staging of men with prostate cancer (PC). To increase interpretive certainty, the standardized PSMA reporting and data system (RADS) has been proposed. Using PSMA-RADS, we characterized lesions in 18 patients imaged with 18F-PSMA-1007 PET/CT for primary staging and determined the stability of semi-quantitative parameters. Six hundred twenty-three lesions were categorized according to PSMA-RADS and manually segmented. In this context, PSMA-RADS-3A (soft-tissue) or -3B (bone) lesions are defined as being indeterminate for the presence of PC. For PMSA-RADS-4 and -5 lesions; however, PC is highly likely or almost certainly present [with further distinction based on absence (PSMA-RADS-4) or presence (PSMA-RADS-5) of correlative findings on CT]. Standardized uptake values (SUVmax, SUVpeak, SUVmean) were recorded, and volumetric parameters [PSMA-derived tumor volume (PSMA-TV); total lesion PSMA (TL-PSMA)] were determined using different maximum intensity thresholds (MIT) (40 vs. 45 vs. 50%). SUVmax was significantly higher in PSMA-RADS-5 lesions compared to all other PSMA-RADS categories (p ≤ 0.0322). In particular, the clinically challenging PSMA-RADS-3A lesions showed significantly lower SUVmax and SUVpeak compared to the entire PSMA-RADS-4 or -5 cohort (p < 0.0001), while for PSMA-RADS-3B this only applies when compared to the entire PSMA-RADS-5 cohort (p < 0.0001), but not to the PSMA-RADS-4 cohort (SUVmax, p = 0.07; SUVpeak, p = 0.08). SUVmean (p = 0.30) and TL-PSMA (p = 0.16) in PSMA-RADS-5 lesions were not influenced by changing the MIT, while PSMA-TV showed significant differences when comparing 40 vs. 50% MIT (p = 0.0066), which was driven by lymph nodes (p = 0.0239), but not bone lesions (p = 0.15). SUVmax was significantly higher in PSMA-RADS-5 lesions compared to all other PSMA-RADS categories in 18F-PSMA-1007 PET/CT. As such, the latter parameter may assist the interpreting molecular imaging specialist in assigning the correct PSMA-RADS score to sites of disease, thereby increasing diagnostic certainty. In addition, changes of the MIT in PSMA-RADS-5 lesions had no significant impact on SUVmean and TL-PSMA in contrast to PSMA-TV.

scholarly journals Metabolic Tumour Volume from PSMA PET/CT Scans of Prostate Cancer Patients during Chemotherapy—Do Different Software Solutions Deliver Comparable Results?

2020 ◽  
Vol 9 (5) ◽  
pp. 1390
Author(s):  
Philipp E. Hartrampf ◽  
Marieke Heinrich ◽  
Anna Katharina Seitz ◽  
Joachim Brumberg ◽  
Ioannis Sokolakis ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Therapy Response ◽  
Tumour Volume ◽  
Ct Scans ◽  
Metabolic Tumour Volume ◽  
Positron Emission ◽  
Psma Pet ◽  
Pet Ct ◽  
Before And After ◽  
Statistical Comparability

(1) Background: Prostate-specific membrane antigen (PSMA)-derived tumour volume (PSMA-TV) and total lesion PSMA (TL-PSMA) from PSMA PET/CT scans are promising biomarkers for assessing treatment response in prostate cancer (PCa). Currently, it is unclear whether different software tools for assessing PSMA-TV and TL-PSMA produce comparable results. (2) Methods: 68Ga-PSMA PET/CT scans from n = 21 patients with castration-resistant PCa (CRPC) receiving chemotherapy were identified from our single-centre database. PSMA-TV and TL-PSMA were calculated with Syngo.via (Siemens) as well as the freely available Beth Israel plugin for FIJI (Fiji Is Just ImageJ) before and after chemotherapy. While statistical comparability was illustrated and quantified via Bland-Altman diagrams, the clinical agreement was estimated by matching PSMA-TV, TL-PSMA and relative changes of both variables during chemotherapy with changes in serum PSA (ΔPSA) and PERCIST (Positron Emission Response Criteria in Solid Tumors). (3) Results: Comparing absolute PSMA-TV and TL-PSMA as well as Bland–Altman plotting revealed a good statistical comparability of both software algorithms. For clinical agreement, classifying therapy response did not differ between PSMA-TV and TL-PSMA for both software solutions and showed highly positive correlations with BR. (4) Conclusions: due to the high levels of statistical and clinical agreement in our CRPC patient cohort undergoing taxane chemotherapy, comparing PSMA-TV and TL-PSMA determined by Syngo.via and FIJI appears feasible.

scholarly journals Estimating the Potential of Radiomics Features and Radiomics Signature from Pretherapeutic PSMA-PET-CT Scans and Clinical Data for Prediction of Overall Survival When Treated with 177Lu-PSMA

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 186
Author(s):  
Sobhan Moazemi ◽  
Annette Erle ◽  
Susanne Lütje ◽  
Florian C. Gaertner ◽  
Markus Essler ◽  
...  
Keyword(s):  
Overall Survival ◽  
Standardized Uptake Value ◽  
Metabolic Tumor Volume ◽  
Ct Scans ◽  
Patient Specific ◽  
Clinical Parameters ◽  
Positron Emission ◽  
Psma Pet ◽  
Pet Ct ◽  
Radiomics Signature

Prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PSMA-PET/CT) scans can facilitate diagnosis and treatment of prostate disease. Radiomics signature (RS) is widely used for the analysis of overall survival (OS) in cancer diseases. This study aims at investigating the role of radiomics features (RFs) and RS from pretherapeutic gallium-68 (68Ga)-PSMA-PET/CT findings and patient-specific clinical parameters to analyze overall survival of prostate cancer (PC) patients when treated with lutethium-177 (177Lu)-PSMA. A cohort of 83 patients with advanced PC was retrospectively analyzed. Average values of 73 RFs of 2070 malignant hotspots as well as 22 clinical parameters were analyzed for each patient. From the Cox proportional hazard model, the least absolute shrinkage and selection operator (LASSO) regularization method is used to select most relevant features (standardized uptake value (SUV)Min and kurtosis with the coefficients of 0.984 and −0.118, respectively) and to calculate the RS from the RFs. Kaplan–Meier (KM) estimator was used to analyze the potential of RFs and conventional clinical parameters, such as metabolic tumor volume (MTV) and standardized uptake value (SUV) for the prediction of survival. As a result, SUVMin, kurtosis, the calculated RS, SUVMean, as well as Hemoglobin (Hb)1, C-reactive protein (CRP)1, and ECOG1 (clinical parameters) achieved p-values less than 0.05, which suggest the potential of findings from 68Ga-PSMA-PET/CT scans as well as patient-specific clinical parameters for the prediction of OS for patients with advanced PC treated with 177Lu-PSMA therapy.

scholarly journals 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

2020 ◽  
Vol 7 (1) ◽  
Author(s):  
Tokiya Yoshii ◽  
Kenta Miwa ◽  
Masashi Yamaguchi ◽  
Kai Shimada ◽  
Kei Wagatsuma ◽  
...  
Keyword(s):  
Image Quality ◽  
Penalized Likelihood ◽  
Ct Images ◽  
Ct Scanner ◽  
Standardized Uptake Values ◽  
Quantitative Accuracy ◽  
Pet Ct ◽  
Optimal Reconstruction ◽  
Normal Spine ◽  
Metastatic Bone Tumor

Abstract 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.

scholarly journals Comparison of standardized uptake values measured on 18F-NaF PET/CT scans using three different tube current intensities

2015 ◽  
Vol 48 (1) ◽  
pp. 17-20 ◽  
Author(s):  
Agnes Araujo Valadares ◽  
Paulo Schiavom Duarte ◽  
Eduardo Bechtloff Woellner ◽  
George Barberio Coura-Filho ◽  
Marcelo Tatit Sapienza ◽  
...  
Keyword(s):  
Attenuation Correction ◽  
Lumbar Vertebra ◽  
Ct Scans ◽  
Femoral Diaphysis ◽  
Standardized Uptake Values ◽  
Pet Ct ◽  
Tube Current ◽  
The Mean ◽  
Humeral Diaphysis ◽  
Ct Studies

Objective: To analyze standardized uptake values (SUVs) using three different tube current intensities for attenuation correction on 18FNaF PET/CT scans. Materials and Methods: A total of 254 18F-NaF PET/CT studies were analyzed using 10, 20 and 30 mAs. The SUVs were calculated in volumes of interest (VOIs) drawn on three skeletal regions, namely, right proximal humeral diaphysis (RH), right proximal femoral diaphysis (RF), and first lumbar vertebra (LV1) in a total of 712 VOIs. The analyses covered 675 regions classified as normal (236 RH, 232 RF, and 207 LV1). Results: Mean SUV for each skeletal region was 3.8, 5.4 and 14.4 for RH, RF, and LV1, respectively. As the studies were grouped according to mAs value, the mean SUV values were 3.8, 3.9 and 3.7 for 10, 20 and 30 mAs, respectively, in the RH region; 5.4, 5.5 and 5.4 for 10, 20 and 30 mAs, respectively, in the RF region; 13.8, 14.9 and 14.5 for 10, 20 and 30 mAs, respectively, in the LV1 region. Conclusion: The three tube current values yielded similar results for SUV calculation.

scholarly journals A Prospective Study Assessing the Post-Prostatectomy Detection Rate of a Presumed Local Failure at mpMR with Either 64CuCl2 or 64CuPSMA PET/CT

Cancers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 5564
Author(s):  
Adriana Faiella ◽  
Rosa Sciuto ◽  
Diana Giannarelli ◽  
Marta Bottero ◽  
Alessia Farneti ◽  
...  
Keyword(s):  
Prospective Study ◽  
Detection Rate ◽  
Previous History ◽  
Distant Metastases ◽  
Salvage Radiotherapy ◽  
Local Failure ◽  
Eligibility Criteria ◽  
Positron Emission ◽  
Psma Pet ◽  
Pet Ct

Background: We aimed assess the detection rate (DR) of positron emission tomography/computed tomography with two novel tracers in patients referred for salvage radiotherapy (sRT) with a presumed local recurrence at multiparametric magnetic resonance (mpMR) after radical prostatectomy (RP). Methods: The present prospective study was conducted at a single institution between August 2017 and June 2020. Eligibility criteria were undetectable PSA after RP; subsequent biochemical recurrence (two consecutive PSA rises to 0.2 ng/mL or greater); a presumed local failure at mpMR; no distant metastases at 18F-fluorocholine PET/CT (CH/PET); no previous history of androgen deprivation therapy. Patients were offered both 64CuCl2 PET/CT (CU/PET) and 64Cu-PSMA PET/CT (PSMA/PET) before sRT. After image co-registration, PET findings were compared to mpMR ones in terms of DR and independent predictors of DR investigated at logistic regression. Results: A total of 62 patients with 72 nodules at mpMR were accrued. Compared to mpMR (DR = 100%, 95%CI: 94.9–100%), DRs were 47.2% (95%CI: 36.1–58.6%) and 54.4% (95%CI: 42.7–65.7%) for CU/PET and PSMA/PET, respectively (p < 0.001 for both). Both experimental PET/CT performed particularly poorly at PSA levels consistent with early sRT. Conclusions: The two novel radiotracers are inferior to mpMR in restaging the prostatic fossa for sRT planning purposes, particularly in the context of early salvage radiotherapy.

scholarly journals PSA and PSA Kinetics Thresholds for the Presence of 68Ga-PSMA-11 PET/CT-Detectable Lesions in Patients with Biochemical Recurrent Prostate Cancer

Cancers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 398 ◽  
Author(s):  
Manuela Andrea Hoffmann ◽  
Hans-Georg Buchholz ◽  
Helmut J. Wieler ◽  
Matthias Miederer ◽  
Florian Rosar ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Characteristic Curve ◽  
Specific Antigen ◽  
Recurrent Prostate Cancer ◽  
Psa Kinetics ◽  
Scan Time ◽  
Positron Emission ◽  
Pet Ct ◽  
Positive Scan ◽  
Previously Treated

68Ga-PSMA-11 positron-emission tomography/computed tomography (PET/CT) is commonly used for restaging recurrent prostate cancer (PC) in European clinical practice. The goal of this study is to determine the optimum time for performing these PET/CT scans in a large cohort of patients by identifying the prostate-specific-antigen (PSA) and PSA kinetics thresholds for detecting and localizing recurrent PC. This retrospective analysis includes 581 patients with biochemical recurrence (BC) by definition. The performance of 68Ga-PSMA-11 PET/CT in relation to the PSA value at the scan time as well as PSA kinetics was assessed by the receiver-operating-characteristic-curve (ROC) generated by plotting sensitivity versus 1-specificity. Malignant prostatic lesions were identified in 77%. For patients that were treated with radical prostatectomy (RP) a PSA value of 1.24 ng/mL was found to be the optimal cutoff level for predicting positive and negative scans, while for patients previously treated with radiotherapy (RT) it was 5.75 ng/mL. In RP-patients with PSA value <1.24 ng/mL, 52% scans were positive, whereas patients with PSA ≥1.24 ng/mL had positive scan results in 87%. RT-patients with PSA <5.75 ng/mL had positive scans in 86% and for those with PSA ≥5.75 ng/mL 94% had positive scans. This study identifies the PSA and PSA kinetics threshold levels for the presence of 68Ga-PSMA-11 PET/CT-detectable PC-lesions in BC patients.

Empfehlungen zur Durchführung der Ganz körper-18F-FDG-PET und -PET/CT bei Kindern mit onkologischen Erkrankungen

2010 ◽  
Vol 49 (06) ◽  
pp. 225-233 ◽  
Author(s):  
J. Stauss ◽  
T. Pfluger ◽  
K. U. Juergens ◽  
R. Kluge ◽  
H. Amthauer ◽  
...  
Keyword(s):  
Nuclear Medicine ◽  
Fdg Pet ◽  
German Society ◽  
Emission Tomography ◽  
Ct Scanner ◽  
High Radiation ◽  
Additional Information ◽  
Paediatric Committee ◽  
Positron Emission ◽  
Pet Ct

SummaryThe purpose of these guidelines is to offer the nuclear medicine and the appropriate interdisciplinary team a framework for performing and reporting positron emission tomography (PET) and the combination with computed tomography (PET/CT) in children with malignant diseases mainly using the radiopharmaceutical 18F-fluorodeoxy-glucose (FDG). These guidelines are based on the recent guidelines of the Paediatric Committee of the European Association of Nuclear Medicine (EANM) (57) and have been translated and adapted to the current conditions in Germany. The adaptation of CT-parameters using PET/CT in children is covered in a more detailed way than in the EANM guideline taking into account that in Germany already a good portion of PET examinations is performed using an integrated PET/CT-scanner. Furthermore, a CT-scan without adaption of the CT acquisition parameters would result in a not tolerably high radiation exposition of the child. There are excellent guidelines for FDG PET and PET/CT in oncology published by the German Society of Nuclear Medicine (Deutsche Gesellschaft für Nuklearmedizin, DGN) (42) and EANM (4). These guidelines aim at providing additional information on issues particularly relevant to PET and PET/CT imaging in children. These guidelines should be taken in the context of local and national current standards of quality and rules.

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