Assessing Ultra-low Dose PET/CT and CT-less PET Using a Long Axial Field-of-view PET/CT System (ULD-PET)

Assessing the Clinical Acceptability of Ultra-low Dose PET/CT and CT-less PET Using a Long Axial Field-of-view PET/CT System: a Single-centre, Single-blinded Method Agreement Study

Latest generation extended axial field-of-view (FOV) PET/CT systems offer the potential for substantial reductions in applied radiopharmaceutical necessary for a clinical scan. However, such low-dose examination protocols have yet to be robustly tested or demonstrated to be non-inferior. Furthermore, extended FOV scanners offer the potential for CT-less attenuation correction of the PET emission data, making clinically acceptable ultra-low dose examination protocols with radiation exposures of < 1 millisievert possible for the first time. The aim of this study is to demonstrate the clinical acceptability of such low and ultra-low dose scanning protocols in a head-to-head prospective study against a full-dose scan using a regular FOV system

Study Overview

• Status: Recruiting
• Conditions: PET/CT
• Intervention / Treatment: Diagnostic test: FD-PET/CT; Diagnostic test: LD-PET/CT

Detailed Description

The first installation of a long-axial field-of-view (LAFOV) PET/CT system occurred in October 2020 at the department for nuclear medicine in Bern. This scanner along with recently introduced total-body scanners (TB-PET/CT) represent a substantial step forward in terms of nuclear medicine imaging technology. In conjunction with recent improvements in time-of-flight resolution and fully-digital detection technology, such systems offer surpassed sensitivity with improvements in image quality, lesion detection and diagnostic certainty. In contrast to LAFOV systems, standard axial field of view (SAFOV) scanners suffer from limited detection efficiency, where 90% of emitted photons go undetected owing to the ability to capture signal from only a small portion of the body (termed "bed position" or "bp").

However, while a number of studies are able to simulate lower applied radiopharmaceutical activities through the re-sampling of PET-sinogrammes or the rebinning of list-mode data, few studies adequately test the application of lower radiopharmaceutical activities, where limited data are available to justify the deviation from clinical routine. The clinical acceptability of such low-dose scans, in terms of lesion detection, image quality and lesion quantification is yet to be determined, which this study aims to address.

• Study Type: Interventional
• Enrollment (Estimated): 42
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Axel O Rominger, MD; Phone Number: 031 632 21 11; Email: firstname.lastname@insel.ch
• Study Contact Backup: Name: Celine Birrer; Phone Number: 031 632 21 11; Email: firstname.lastname@insel.ch

Study Locations

• Switzerland
  • Bern, Switzerland, 3010
    • Recruiting
    • Inselspital, Universitätsspital Bern

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Adults (>18 years) able to provide informed consent for inclusion, willing and able to undergo a PET/CT for the detection or staging of cancer.
• Individuals undergoing a PET/CT with 18F-FDG for the investigation of known or suspected NSCLC.
• Upper fasting plasma glucose levels of <8.3 mmol/L (<150 mg/dL) (as measured >30 mins prior to the administration of the radiopharmaceutical).

Exclusion Criteria:

• Patients who are unable to consent to a second study-specific examination
• Patients with claustrophobia requiring medication.
• Patients who commence active treatment of a cancer or other pathology between scans.
• Patients who have not fasted for > 4 hours prior to the study.
• Insulin dependent diabetics.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Diagnostic
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Single Arm; Patients will receive both a standard of care PET/CT and a low dose PET/CT	Diagnostic test: FD-PET/CT; Standard of care PET/CT with full dose (FD) of the radiopharmaceutical; Diagnostic test: LD-PET/CT; Additional low dose PET/CT performed within protocol defined time frame LD-PET/CT with additional ultra-low dose CT-less reconstruction

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intra-rater correlation coefficient	ICC for Cancer Stage using the union for international cancer control (UICC) TNM (T= tumor, N= nodal stage, M = metastasis) System (8th Edition) for low dose positron emission and computed tomography (LD-PET/CT) exams compared to the standard of care (SOC) full-dose (FD)-PET/CT as assessed by a panel of physicians	2-6 weeks following scan

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intra-rater correlation coefficient	ICC for ultra-low dose (ULD)-PET/CT compared to FD- and LD-PET/CT	2-6 weeks following scan
Lesion uptake	Composite outcome assessing lesion quantification in terms of peak standardised uptake value (SUVpeak), tumour to background (TBR), metabolic tumour volume (MTV) and tumour glycolytic activity (TLG) for ULD- and LD-PET/CT compared to the standard of care FD-PET/CT	2-6 weeks following scan
Image quality	Composite outcome assessing image quality in terms of tumour to background ratio (TBR) and signal to noise (SNR), defined as the reciprocal coefficient of variation (COV) for ULD- and LD-PET/CT compared to the standard of care FD-PET/CT	2-6 weeks following scan
Subjective quality	Image quality (subjective) as rated by five independent nuclear medicine physicians on a five-point Likert scale (1= unacceptable, 2=poor, 3=moderate, 4=good, 5=high) for ULD- and LD-PET/CT compared to the standard of care FD-PET/CT	2-6 weeks following scan
Agreement	Inter-reader agreement for the primary outcome (UICC cancer stage) shall be compared between LD and FD-PET/CT	2-6 weeks following scan
Diagnostic accuracy	Assessment of the positive predictive value (PPV) for LD- and FD-PET/CT for patients who undergo surgery or bronchoscopy and where histopathological confirmation of true positive (TP) and false positive (FP) findings are available	2-6 weeks following scan

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Acceptability	Additional outcome of interest: Patient and referrer acceptability of low-dose PET/CT examinations examined by means of a structured questionnaire.	2-6 weeks following scan

Collaborators and Investigators

• Sponsor: Insel Gruppe AG, University Hospital Bern
• Investigators: Study Chair: Axel O Rominger, MD, Inselspital

Study record dates

Study Major Dates

• Study Start (Actual): September 13, 2022
• Primary Completion (Estimated): August 31, 2024
• Study Completion (Estimated): March 31, 2025

Study Registration Dates

• First Submitted: August 8, 2022
• First Submitted That Met QC Criteria: August 8, 2022
• First Posted (Actual): August 11, 2022

Study Record Updates

• Last Update Posted (Actual): May 8, 2024
• Last Update Submitted That Met QC Criteria: May 7, 2024
• Last Verified: May 1, 2024

More Information

Terms related to this study

• Keywords: PET/CT, low dose, long-axial field-of-view, extended field-of-view, total-body PET
• Other Study ID Numbers: 2022-D0038

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No