This study aimed to estimate the diagnostic accuracy and stage migration of [18F]PSMA-1007 PET/CT and its impact on patient management when compared with [18F]NaF PET/CT for primary staging of prostate cancer (PCa). Methods: In a substudy of the PRISMA-PET trial (EudraCT 2021-000123-12), patients with intermediate- and high-risk primary PCa were clinically staged using [18F]PSMA-1007 PET/CT with contrast-enhanced CT (ceCT). A masked [18F]NaF PET/CT was also performed for research purposes only. A research-focused multidisciplinary team (rMDT) conference was then conducted, beginning with the presentation of patient data. [18F]NaF PET/CT and ceCT results were presented, with masked results from the [18F]PSMA-1007 PET/CT, and stage and treatment decisions were made by consensus. Subsequently, the [18F]PSMA-1007 PET/CT results were reviewed, and the decisions were reconsidered. Final rMDT decisions, incorporating all imaging and available histology results, formed the composite reference standard. Diagnostic accuracy, stage migration, and treatment decision were compared. Treatment decisions made by the rMDT were compared with the clinical treatment decisions made. Results: In total, 128 men (median age, 72 y) were included in this study. Of these, 25 (19.5%) had intermediate-risk PCa and 103 (80.5%) had high-risk PCa. Our results revealed significantly higher accuracy in diagnosing lymph node metastases with [18F]PSMA-1007 PET/ceCT compared with ceCT with [18F]NaF PET/CT (P = 0.021). There was no significant difference for diagnosing bone metastases. Stage migration was observed in 22 patients (17%); 15 (12%) were upstaged and 7 (5%) downstaged. Treatment management changed for 18 patients (14%): 5 had altered curative strategy but the intent remained curative, 8 shifted from curative to life-prolonging treatment, 2 moved from life-prolonging to curative treatment, and 3 had adjustments within life-prolonging strategies. Forty patients received treatment that deviated from the rMDT decision. Conclusion: Staging PCa with [18F]PSMA-1007 PET/CT versus [18F]NaF PET/CT led to stage migration for 17% of patients and treatment management change for 14% of patients. Follow-up results from the PRISMA-PET trial will clarify the impact on patient outcomes.

Studies evaluating [18F]fluorocholine PET/CT for parathyroid adenoma localisation fail to report the injection method used. At our department, manual injection method (MIM) was initially used, before converting to an automated injection system (AIS). Afterwards, physicians observed increased retention of the radiotracer within the veins leading from the injection site, which had not been as present previously. The aim of this study was to evaluate whether the injection method had a clinical impact. The study compared two groups consisting of 60 patients, where the injection method was the only difference. Two physicians, blinded to injection method, evaluated if retention was present and interpretation was jeopardised. Quantitative measures were determined based on the original diagnostic confidence scores (DCS) for each suspected lesion, as these were compared between patient groups. Additionally, the maximum standardised uptake values (SUVmax) were measured for the suspected lesions along with the thyroid and salivary glands as a physiological reference point. Comparisons of the quantitative parameters were also performed between patients with or without retention. There was significant more occurrence of retention in AIS-group (83.3

The diagnostic accuracy of [18F] FDG PET/CT versus CT for NSCLC surveillance was compared using data from 692 patients from a randomized clinical trial. Compared to CT, PET/CT demonstrated higher sensitivity (88% vs. 62%, P < .001) but lower specificity (89% vs. 96%, P < .001) and overall accuracy (89% vs. 93%, P = .003) for detecting recurrence. Background: Following curative treatment for non-small cell lung cancer (NSCLC), surveillance to detect recurrence is recommended. While computed tomography (CT) is the current standard for follow-up imaging, the optimal surveillance strategy remains debated. This study compares the diagnostic accuracy of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT; hereafter referred to as PET/CT) and CT for NSCLC surveillance. Materials and Methods: This study represents a secondary analysis of data from a randomized controlled trial (SUPE_R, ClinicalTrials.gov NCT03740126) of patients with stage IA-IIIC NSCLC who completed curative-intent treatment between February 2019 and February 2022. CT and PET/CT scans were compared for recurrence detection using biopsy, multidisciplinary team assessment, or follow-up imaging as reference standards. Results: The analysis included 899 PET/CT scans and 852 CT scans from 692 patients (mean age 69 years +/- 8 [SD]; 412 female). For detecting recurrence, PET/CT demonstrated a higher sensitivity (88% [95% CI, 80%-93%] vs. 62% [95% CI, 50%- 73%]; P < .001) but lower specificity (89% [95% CI, 86%-91%] vs. 96% [95% CI, 94%-97%]; P < .001) compared to CT. PET/CT demonstrated a higher sensitivity compared to CT after treatment with chemoradiotherapy (100% [95% CI, 72%-100%] vs. 46% [95% CI, 19%-75%]; P = .006) and at 0 to 6 month after treatment (83% [95% CI, 63%-94%] vs. 41% [95% CI, 21%-65%]; P = .008). Conclusion: The higher sensitivity of PET/CT, particularly after chemoradiotherapy and early post-treatment, suggests it may be particularly valuable in these high-risk scenarios. However, CT remains preferred for routine surveillance of low-risk patients given its superior specificity.

OBJECTIVE:To evaluate the sensitivity of a stepwise preoperative imaging regimen for patients with primary hyperparathyroidism. STUDY DESIGN:Prospective cohort study. SETTING:A high-volume tertiary referral center for parathyroidectomy. METHODS:Patients with primary hyperparathyroidism referred for parathyroidectomy underwent surgeon-performed ultrasound as the primary preoperative imaging examination. The diagnostic confidence of the examiner on a scale from 0 to 3 determined whether additional imaging was acquired. If ultrasound identified an enlarged parathyroid gland with certainty (score 3), the patient was booked directly for surgery. If the confidence score was <3, the patient underwent either parathyroid scintigraphy or 18F-choline PET/CT. The gold standard was the intraoperative location of pathological parathyroid glands combined with biochemical cure ≥6 months after surgery. The primary endpoint was the sensitivity of the stepwise imaging regimen per patient, irrespective of the number of acquired imaging modalities. Secondary endpoints were the sensitivity per gland and the sensitivity of the imaging regimen if the cut-off for additional imaging had been a confidence score of 1 or 2. RESULTS:Upfront ultrasound spared 49 of 99 patients (49.5%) from additional imaging and correctly localized ≥1 pathological parathyroid gland in 98.0% of patients [95% CI 92.9-99.8]. The per-gland sensitivity was 92.5% [95% CI 84.8-1.0]. When changing the cut-off to a confidence score of 2, the per-patient sensitivity remained 98.0% [95% CI 92.9-99.8]. CONCLUSION:Our study demonstrates that a stepwise imaging regimen based on upfront ultrasound by an experienced examiner can substantially reduce the number of radiation-based supplemental scans, while maintaining a high sensitivity.

Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) has shown promise for post-treatment surveillance in patients with non-small cell lung cancer (NSCLC). This study evaluated interobserver agreement of PET/CT interpretation for NSCLC surveillance in a multicenter setting. Nine teams from seven centers, each team consisting of a nuclear medicine specialist and a radiologist, participated in the study. A total of 150 PET/CT scans were selected, and each was independently reviewed by two randomly assigned teams. Scans were performed six months post-treatment for scheduled recurrence assessment in stage Ia-IIIc NSCLC patients. Each scan was evaluated for suspicion of recurrence using two methods; without any pre-specified criteria (conventional assessment) and using pre-specified, qualitative criteria (Hopkins criteria). Both scoring methods were compared to a reference standard to assess accuracy. Conventional assessment showed moderate interobserver agreement (κ = 0.55, 95

INTRODUCTION:Post-treatment surveillance is recommended for NSCLC owing to a high risk of recurrence, but evidence on the optimal surveillance method is lacking. This trial evaluates fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT) versus contrast-enhanced CT (ceCT) for surveillance in patients with NSCLC. METHODS:In this multicenter, randomized controlled trial (SUPE_R, ClinicalTrials.gov NCT03740126), patients with stage IA-to-IIIC NSCLC were randomized one-to-one to standard surveillance (ceCT) or surveillance with [18F]FDG PET/CT after completion of curative treatment. The primary outcome was the proportion of recurrences treated with curative intent. Secondary outcomes included time to recurrence (TTR) and overall survival (OS). RESULTS:Between February 2019 and February 2022, 750 patients were randomized to PET/CT (n = 373) or CT (n = 377). Recurrences occurred in 164 patients (22%). The proportion of recurrences treated with curative intent was identical in the PET group (42/87) and CT group (37/77), both 48% (p = 0.98). More recurrences were detected through scheduled follow-up in the PET group (90%) than in the CT group (77%; p = 0.02). There were no significant differences in TTR (hazard ratio 1.12, 95% confidence interval 0.82-1.52, p = 0.48) or OS (hazard ratio 0.97, 95% confidence interval 0.66-1.43, p = 0.89) between groups. CONCLUSIONS:Surveillance with [18F]FDG PET/CT did not improve rates of curatively treated recurrences, TTR, or OS compared with ceCT in patients with NSCLC after curative treatment. These findings do not support the routine use of [18F]FDG PET/CT for post-treatment surveillance in this patient population.

A disadvantage of 18F-NaF PET/CT compared with other types of bone scintigraphy is the additional radiation dose from the standard whole-body CT scan for lesion localization and characterization (L/C). This study investigated whether the L/C CT region can be personalized to reduce CT radiation dose, according to uptake in the PET images. Methods: Attenuation-corrected 18F-NaF PET images were reviewed for the clinically required L/C CT range by 1 medical observer and 1 technologist observer in 25 patients with breast cancer scanned before neoadjuvant chemotherapy. For each patient, effective doses were estimated for whole-body L/C CT, personalized L/C CT, and whole-body CT for attenuation correction only. Dose savings for the personalized method incorporating both whole-body CT for attenuation correction and personalized L/C CT were expressed relative to standard whole-body L/C CT. The clinical impact of the personalized method was determined by evaluating whether lesions clinically requiring coverage had been missed from the L/C CT region. Results: Potential dose savings of 43%-54% were estimated for the personalized CT method, according to the observers. From the 25 patients reviewed, the medical observer did not miss any clinically significant lesions from the L/C CT region, whereas the technologist observer missed 2 clinically significant lesions of 61 suggestive lesions identified by medical observer follow-up. Conclusion: Mean CT dose could be reduced by around half in this patient group with personalized CT. Future work should further evaluate whether this method can be implemented in clinical practice without compromising clinical image evaluation.

BACKGROUND:Following curative treatment for non-small cell lung cancer (NSCLC), surveillance to detect recurrence is recommended. While computed tomography (CT) is the current standard for follow-up imaging, the optimal surveillance strategy remains debated. This study compares the diagnostic accuracy of fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ([18F]FDG PET/CT; hereafter referred to as PET/CT) and CT for NSCLC surveillance. MATERIALS AND METHODS:This study represents a secondary analysis of data from a randomized controlled trial (SUPE_R, ClinicalTrials.gov NCT03740126) of patients with stage IA-IIIC NSCLC who completed curative-intent treatment between February 2019 and February 2022. CT and PET/CT scans were compared for recurrence detection using biopsy, multidisciplinary team assessment, or follow-up imaging as reference standards. RESULTS:The analysis included 899 PET/CT scans and 852 CT scans from 692 patients (mean age 69 years ± 8 [SD]; 412 female). For detecting recurrence, PET/CT demonstrated a higher sensitivity (88% [95% CI, 80%-93%] vs. 62% [95% CI, 50%-73%]; P < .001) but lower specificity (89% [95% CI, 86%-91%] vs. 96% [95% CI, 94%-97%]; P < .001) compared to CT. PET/CT demonstrated a higher sensitivity compared to CT after treatment with chemoradiotherapy (100% [95% CI, 72%-100%] vs. 46% [95% CI, 19%-75%]; P = .006) and at 0 to 6 month after treatment (83% [95% CI, 63%-94%] vs. 41% [95% CI, 21%-65%]; P = .008). CONCLUSION:The higher sensitivity of PET/CT, particularly after chemoradiotherapy and early post-treatment, suggests it may be particularly valuable in these high-risk scenarios. However, CT remains preferred for routine surveillance of low-risk patients given its superior specificity.

Abstract Background The tin filter has allowed radiation dose reduction in some standalone diagnostic computed tomography (CT) applications. Yet, ‘low-dose’ CT scans are commonly used in positron emission tomography (PET)-CT for lesion localisation/characterisation (L/C), with higher noise tolerated. Thus, dose reductions permissible with the tin filter at this image quality level may differ. The aim was to determine the level of CT dose reduction permitted with the tin filter in PET-CT, for comparable image quality to the clinical reference standard (CRS) L/C CT images acquired with standard filtration. Materials and methods A whole-body CT phantom was scanned with standard filtration in CRS protocols, using 120 kV with 20mAs-ref for bone L/C (used in 18F-Sodium Fluoride (NaF) PET-CT) and 40mAs-ref for soft tissue L/C (used in 18F-Fluorodeoxyglucose (FDG) PET-CT), followed by tin filter scans at 100 kV (Sn100kV) and 140 kV (Sn140kV) with a range of mAs settings. For each scan, effective dose (ED) in an equivalent-sized patient was calculated, and image quality determined in 5 different tissues through quantitative (contrast-to-noise ratio) and qualitative (visual) analyses. The relative dose reductions which could be achieved with the tin filter for comparable image quality to CRS images were calculated. Results Quantitative analysis demonstrated dose savings of 50–76% in bone, 27–51% in lung and 8–61% in soft tissue with use of the tin filter at Sn100kV. Qualitative analysis demonstrated dose reductions using Sn100kV in general agreement with the dose reductions indicated by quantitative analysis. Overall, CT dose reductions of around 85% were indicated for NaF bone PET-CT, allowing whole-body CT at just 0.2mSv ED, and a 30–40% CT dose reduction for FDG PET-CT using Sn100kV (1.7-2.0mSv), providing comparable image quality to current CRS images with standard filtration. Sn140kV demonstrated limited value in CT dose reduction. Conclusions Large CT dose reductions can be made using the tin filter at Sn100kV, when imaging bone, lung and soft tissue at L/C level CT image quality in PET-CT. As well as reducing the risk of inducing a cancer in later life, such dose reductions may also impact PET-CT practice, such as justifying cross-sectional over planar imaging or justifying PET-CT in younger patients.

Purpose:Myocardial perfusion imaging (MPI) procedures from single photon emission computed tomography and positron emission tomography imaging have been registered in the Western Denmark Heart Registry (WDHR) since 2017 as a sub-registry (WDHR-MPI). The aim was to review the content, quality, and research potential of the WDHR-MPI and assess the completeness and validity of its key variables. Patients and Methods:Using the Danish National Patient Registry (DNPR) as a reference, we calculated the completeness of procedure registration as the proportion of procedures registered in the WDHR-MPI from 2017 to 2021. We defined completeness of variable registration as the proportion of non-missing values for a given variable and examined it for 38 key variables. We assessed validity by estimating the positive predictive values (PPV) and negative predictive values (NPV) with 95% confidence intervals (CI) for 26 selected key variables using corresponding extracted information from 300 randomly selected patient records. Results:We identified 19,084 procedures in 17,871 patients from all seven cardiac centers performing nuclear cardiology procedures in the WDHR uptake area. The registry accumulated 4000-6000 procedures each year from 2019 to 2021. The overall completeness of procedure registration was 72% (95% CI 72-73), increasing from 14% (95% CI 13-15) in 2017 to 98% (95% CI 98-98) in 2021. The mean completeness of variable registration was 89%. The validity of entered data was high, with an overall PPV for the selected key variables of 95% (95% CI 94-95) and NPV of 94% (95% CI 93-96). Conclusion:The WDHR-MPI is one of the largest systematic MPI cohorts. The overall high completeness and validity of the data support its potential for cardio-epidemiological research.