Proposed Topic (Most preferred): :
Clinical Safety and Quality Service II (Projects aiming to enhance clinical safety and outcomes, clinical governance / risk management)
Proposed Topic (Second preferred): :
HA Young Investigators Session (Projects to be presented by HA staff who had joined HA for 10 years or less)
Authors (including presenting author) :
Chow TK (1), Ma WH (1)
Affiliation :
(1) Nuclear Medicine Unit, Department of Radiology and Nuclear Medicine, Tuen Mun Hospital
Introduction :
The standardized uptake value (SUV) is a semi-quantitative measure used to assess the activity of a tracer within a lesion, which is then normalized to a distribution volume, typically through normalization to the patient's body weight. In the context of F-18 Fluorodeoxyglucose (FDG) PET/CT imaging, SUV serves as an indicator of the tumor's glucose metabolism. The calculation of SUV is crucial for lesion characterization, monitoring treatment response, and predicting prognosis in oncological imaging. In clinical practice, SUV calculation involves the input of various parameters, including patient body weight, injected tracer dose and time, as well as residual dose and time. These data are manually entered into the PET/CT console by the user. Even minor inaccuracies during data entry can result in incorrect SUV in the PET/CT studies. Consequently, such errors can lead to misinterpretation of images and significantly impact the assessment of treatment response in subsequent follow-up studies.
Objectives :
The objective of this clinical audit is to assess the accuracy of data entry for SUV computation in Tuen Mun Hospital (TMH) PET/CT Centre, identify possible causes of error and suggest recommendations for improvement.
Methodology :
A retrospective clinical audit was conducted at TMH to assess the accuracy of data entry for SUV computation in FDG PET/CT scans. The audit included all consecutive patients referred to TMH PET/CT Centre between 1-April-2021 and 30-April-2021, and their data were retrieved from the Radiology Information System (RIS). The patient documentation and PET/CT console were reviewed retrospectively to identify eight specific parameters related to SUV computation, including patient body weight, unit of patient body weight (kg/lbs), pre-injected dose of radiopharmaceutical, unit of pre-injected dose (mCi/MBq), time of measuring pre-injected dose, post-injected dose of radiopharmaceutical, unit of post-injected dose (mCi/MBq), and time of measuring post-injected dose. These eight parameters were derived from the latest international guideline for FDG PET/CT imgaing published by European Association of Nuclear Medicine. The accuracy of the entered data in the PET/CT console was then calculated. The target was to achieve 100% accuracy for all eight parameters.
Result & Outcome :
A total of 97 patients were included in this retrospective audit, encompassing the designated period. None of the patients were excluded from the analysis. The indications for FDG PET/CT scans among these patients were as follows: 90 patients for the assessment of malignancy or suspected malignancy, 5 patients for the evaluation of pyrexia of unknown origin or systemic inflammatory disease, and 2 patients for the assessment of dementia.
The overall performance regarding the accuracy of data entry for SUV computation was deemed satisfactory. Among the previously mentioned eight parameters, six of them achieved a 100% accuracy rate. However, minor errors in data entry were observed for two parameters: patient body weight (97.9% accuracy) and time of measuring post-injected dose (99.0% accuracy). These errors occurred in two patients, with one patient experiencing mistakes in two parameters. After rectifying the data input in the PET/CT console, there was only a negligible change in the SUV for these two cases. Consequently, the diagnosis and management plans were unlikely to be affected significantly.
The findings of this audit were presented and discussed during the audit meeting held at TMH Nuclear Medicine Unit on June 30, 2021. It was speculated that the errors in data entry may have arisen from inexperience or lack of awareness among junior radiographers. Through the discussion of the audit results, it was anticipated that the awareness among colleagues regarding the importance of accurate data entry for SUV computation would be heightened. Suggestions were made to provide mentored support to junior or new staff by more experienced colleagues and to conduct regular re-audits to monitor and improve data entry accuracy. Similar clinical audit may also be carried out in other PET/CT centres to ensure clinical safety.
