1. Fig 1.
Proposed Diagnostic Reference Levels for 3  Common Cardiac Interventional Procedures: an all-Ireland Investigation 
Collaborative project between University College Dublin, Ireland
& the University of Ulster at Jordanstown, Belfast.
C. D’Helft, S. Mc Fadden, A. McGee, L. Rainford, C. Hughes, J. Winder & PC. Brennan
PURPOSE :
The number of interventional radiological procedures performed has risen in recent years because of their cost-effectiveness when compared with surgical procedures. Due to the prolonged fluoroscopic exposure times encountered during interventional procedures, cardiovascular studies are often responsible for some
of the highest patient and staff radiation doses [1]. Such exposures increase the risk of stochastic radiation effects and regularly cross the threshold dose above which direct, deterministic effects are experienced by the patient [2,3]. Radiation doses for cardiac interventional procedures in Ireland are currently being compared to those recorded by the DIMOND EU project and the Health Protection Agency’s ‘National Patient Dose Database’ (NPDD).
MATERIALS & METHODS :
This poster illustrates some of the findings obtained from the 22 specialised adult catheterisation suites being surveyed. The work focuses on hospitals in both the Republic and Northern Ireland. Radiation dose levels and procedural information are being determined and compared for coronary angiograms (CA), percutaneous coronary intervention (PCI) and permanent pacemaker insertion procedures (PPI). Radiation dose levels are being recorded using calibrated dose area product meters.
Other factors being documented include:
Patient data: age, gender, body mass index (BMI);
Grade of cardiologist;
Projections acquired/technique employed;
Equipment used;
Complexity score for all examinations [4,5];
Exposure factors: kVp / mA / fluoroscopic exposure time / length of cine run / single and biplane image acquisition options.
RESULTS :
DAP meter readings & Fluoroscopic exposure times (hospital data combined)
CA: Average: ,786.9 cGycm² mins
Range: – 23,101 cGycm² mins
PCI: Average: ,136.9 cGycm² mins
Range: – 41,308 cGycm² mins
PPI: Average: ,736.6 cGycm² mins
Range: ,192 cGycm² – 54.5 mins
It has been noted that due to the large number of variables possible within each procedure, that further sub categories could be separated, however this has not been done in this case as the aim is to show an average procedure. COMPARISON OF REFERENCE LEVELS :
DIMOND-Values as proposed by the DIMOND EU PROJECT [6]
NPDD- Values as proposed by the National Patient Dose Database set up by the NRPB now HPA. [7]
CAUSAL AGENTS :
Stepwise regression analysis demonstrated that in addition to fluoroscopic exposure time, body mass index and examination complexity, cardiologist grade was a significant causal agent for dose variation, with the higher doses associated with the more experienced clinician. This was not linked to the complexity of procedures and requires further investigation.
Mean doses & times across the hospitals investigated for the three examinations are shown in figures 1-6. The red and green lines illustrate the combined hospitals overall mean and third quartile values respectively. A blank space represents a catheterisation suite. where the specified procedure was not performed.
Fig 1.
Fig 2.
Fig 3.
Fig 4.
Fig 5.
Fig 6.
CONCLUSIONS :
Due to the risks associated with radiation, patient dose should be kept as low as reasonably achievable, consistent with maintaining image quality. Whilst setting reference levels for these complex procedures has some difficulties, it is important that some benchmark values are available as a guideline to the operators an departmental personnel. The setting of reference dose levels and the establishment of optimum practice as investigated in this study should reduce radiation dose and image quality variation for these relatively common interventional procedures.
REFERENCES
1. Vano E, Arranz L, Sastre J M, Moro C, Ledo A, Garate M T, Minguez I. Dosimetric and radiation protection considerations based on some cases of patient skin injuries in interventional cardiology. Br J Radiol; 71 (1998); pp
2. Vano E, Gonzalez L, Fernandez J M, Guibelalde E (1995). Patient dose values in interventional radiology. Br J Radiol; Nov; 68(815); pp
J. Interv Cardiol; 17(3); pp
3. Vlietstra R E, Wagner L K, Koenig T, Mettler F (2004) Radiation burns as a severe complication of fluoroscopically-guided cardiological interventions.
4. Bernardi G, Padovani R, Morocutti G, Vano E, et al (2000). Clinical and technical determinants of the complexity of Percutaneous Transluminal Coronary Angioplasty: Analysis in relation to radiation exposure.
Catheterization and Cardiovascular Interventions; 51, 1-9.
5. Padovani R, Bernardi G, Malison M R, Vano E, Morocutti G, Fioretti PM. (2001) Patient dose related to the complexity of interventional cardiology procedures. Radiation Protection Dosimetry. Vol. 94, No.1-2, pp
6. Neoffotistou V, Vano E, Padovani R, Kotre J, Dowling A, Toivonen M, Kottou S, Tsapaki V, Willis S, Bernardi G, Faulkner K. (2003). DIMOND EU PROJECT. Preliminary reference levels in interventional cardiology.
Eur Radiol Oct;13(10): pp
7. Hart D, Hillier M C, Wall B F (2000) NRPB- W 14. Doses to patients from medical x-ray examinations in the UK review
3rd Quartile Values CA
PCI
PPI
DAP (cGycm²)
NPDD
DIMOND
This study
3,630
5,700
4,654
6,340
9,400
10,650
2,650 -
1,686
Time (min)
5.6 6 5
14.6 16 18
10.7
7.7