Minimum Standards for PET-CT Centres to Participate in Multicentre Trials

These standards reflect the current criteria that PET-CT centres need to conform to in order to be accredited by the UK PET Core Lab. These standards were originally developed by the St Thomas' Clinical Trials Network and adopted by the NCRI Clinical Trials Network for multicentre trials. These standards are regularly reviewed and may be subject to change for future trials.

Named persons (and their deputies) should be identified with responsibility for scanning, quality control (QC), and data transfer procedures at participating PET-CT centres.

Scanning Procedures

• Only full-ring dedicated PET-CT scanners capable of 3D acquisition are acceptable.
• PET scans must be performed within the time frames required by the trial protocol to fit in with the patient's treatment schedule.
• For patients undergoing multiple scans, these must be performed at the same centre and on the same scanner as the baseline scan.
• The proposed PET acquisition and reconstruction protocol (including details of the time per bed position and overlap or scan speed, the CT settings, and reconstruction parameters) must be agreed upon with the Core Lab before scanning can start.
• Any changes to the PET-CT acquisition or reconstruction parameters must be agreed with the Core Lab before implementation. Sites may be asked to submit additional data to demonstrate that image quality and semi-quantitative measures, such as standardised uptake values (SUV), are not significantly altered.

Quality Control

• A documented quality assurance programme must be in place and records kept covering daily, monthly, quarterly, and annual QC testing. Details of the routine QC must be sent to the Core Lab along with example results.
• The manufacturer’s routine QC should be performed, and the PET-CT scanner should have an up-to-date calibration and normalisation.
• PET-CT scanners to be used for the trial should be calibrated against the institution’s own radionuclide calibrator used for assay of patient injections.
• As a minimum, routine CT QC must include the acquisition of a water-filled phantom on a weekly basis. Measurements should include HU accuracy for water, image noise, and uniformity as described in IPEM Report 91.
• Scanning sites must inform the Core Lab of any upgrades to the scanner hardware or software prior to the upgrade. Sites may be asked to submit additional data to demonstrate that image quality and semi-quantitative measures, such as standardised uptake values (SUV), are not significantly altered.
• It must be demonstrated that image quality is comparable between centres and that standard uptake values can be reliably determined from the PET images. This will be achieved by the regular submission of phantom data.
• On initial accreditation, a minimum of 8 weeks of consecutive SUV measurements using a uniform ⁶⁸Ge resin or ¹⁸F phantom must be sent to the Core Lab for assessment of scanner stability.
• Ideally, a uniform phantom should be scanned prior to the start of each scanning session in which a patient is to be scanned as part of the trial. This can either be a resin ⁶⁸Ge phantom (where available) or an ¹⁸F water-filled phantom. The average SUV for a large ROI placed at the centre of the phantom must be 1.00 ± 10% and ideally within 5%. On visual inspection, the image should show no artefacts.
• As PET uses SUVs defined in terms of patient weight, the scales used to weigh the patients must fulfil the essential requirements of a class III machine as defined in The Non-automatic Weighing Instruments Regulations 2016. This must be demonstrated as part of the initial QC.
• The BM glucometer QC should be performed according to the manufacturer’s or institution’s procedure to ensure proper functioning.
• Quality assurance procedures for the radionuclide calibrator must be in place, and activity measurements for ¹⁸F should be traceable to a primary standard. QC tests should include daily constancy checks and annual accuracy and linearity checks.
• The clocks used to record the assay time and injection time must be synchronised to the scanner time.

Data Transfer

• Procedures should be in place to ensure image data is sent promptly to the Core Lab to allow central reporting to fit in with patient treatment schedules (in some cases, within 48 hours).
• A tested and secure method for transferring pseudo-anonymised scan data between scanning facilities and the UK PET Core Lab should be established.
• All image files must be compliant with DICOM PART 10 format.
• All image files must be correctly pseudo-anonymised and clearly named using the pre-arranged file naming conventions (as specified in the Trial Imaging Manual).
• For each patient study, data acquisition information and patient information should be recorded and sent to the Core Lab at the same time as the image data is transferred.
• All reconstructed CT, attenuation-corrected PET, and non-attenuation-corrected PET data must be saved locally on an approved data storage device. Raw PET data should be archived according to local policy, at least until the images have been accepted by the UK PET Core Lab in case additional reconstructions are required.