Objectives

1. To arrive at a consensus on image criteria for new detectors and new cardiac procedures
2. To propose reference levels for new cardiac procedures and new detectors
3. Collate information on the assessment of image quality and dose performance of new imaging modalities in cardiology

Description of work

1. Collation and standardisation patient and staff dose studies
2. Development and standardisation of image quality criteria for new detectors based upon literature review
3. Evaluate existing acceptance, status and constancy test protocols for new detectors, contribute to standardisation

Deliverables

1. Performance of new detectors and patient / staff dose.
2. Approaches to image quality, reference doses and optimisation in cardiology.
   

Workpackage description

As part of this work package, results of surveys already performed by partners will be coordinated. Results from these European surveys of image quality and patient dose in cardiac procedures will be analysed. This is necessary as the practise in cardiology is the subject of rapid growth and change. Thus the results of a survey of diagnostic and therapeutic heamodynamic/electro physiology procedures will be analysed to identify high dose procedures and those procedures most in need of optimisation. An analysis of images acquired from a sample of patients and institutes will permit the definition of image quality needs. This survey will provide information on the impact of new emerging technologies on clinical practice and patient doses.

From this initial survey image quality criteria for cardiac procedures using new detectors will be developed. Using image quality criteria for coronary angiographic images previously, criteria for other cardiac radiological procedures will be investigated by extending existing studies. This study will include electrophysiology and procedures performed with emerging technology. This will be followed by a consensus meeting to analyse a sample of images acquired from a broad range of clinical centres. The acceptability of the proposed criteria will be assessed.

Patient dosimetry results collected as part of the clinical audit process will be collated and analysed to establish reference doses for a wide range of cardiac procedures. These will be complemented by staff dosimetry studies in some centres.

In cardiology, new techniques will replace fluoroscopy using image intensifier television systems. It will therefore, be important to determine referral criteria for cardiac procedures on new equipment. These referral criteria will need to take into account imaging and dose performance, the diagnostic information required and any economic implications of using an expensive/rare imaging device. Guidelines for referral criteria for new cardiac imaging modalities will be developed and a consensus meeting arranged.

As part of this project the establishment of a dosimetry database for future epidemiological studies into the effects of radiation will be explored. Patients undergoing cardiac procedures can receive relatively high organ doses which will have an associated increase in the probability of the occurrence of stochastic radiation effects. Consistent dosimetry approaches will be used to assess organ doses. Agreement on the contents of this database will be achieved. The establishment in the future of a European Registry will permit epidemiological studies to be performed to assess radiation risk at low and intermediate levels for partial body irradiation. The database can be extended to include other high dose procedures as well and will be used to develop reference doses. To facilitate data collection, methods for analysing the DICOM header for cardiac images will be developed. This will also permit the audit of existing clinical protocols.

The image quality and dose performance of these new systems would have to be assessed by a series of surveys by end users anyway. Coherent and consistent methods for acceptance, status and constancy testing of angiographic systems with flat panel detectors are required and will be developed using the results of these surveys. It will be necessary to assess image quality using both quantitative and qualitative quantities and to take into account the effects of digital post processing. Performance comparisons with image intensifier television systems for coronary angiography will be made. The techniques developed in this work package will be used to inform the standardisation process of the International Electrotechnical Commission.

Deterministic injuries are a particular concern in cardiology. It is imperative to develop robust methodology for evaluating maximum entrance surface air kerma at the patients' skin. This quantity closely correlates with the appearance of skin injuries in patients who have had long fluoroscopic procedures. Current approaches are unsatisfactory for skin dose evaluation and new methods need to be developed.

New imaging modalities require the development of specific training materials for the radiation protection of patients and staff. This will include advice on the optimisation of procedures.