Cardiovascular Journal of Africa: Vol 32 No 5 (SEPTEMBER/OCTOBER 2021)

CARDIOVASCULAR JOURNAL OF AFRICA • Volume 32, No 5, September/October 2021 AFRICA 235 Editorial Radiation exposure protection: small things matter DG Buys, SC Brown DOI: 10.5830/CVJA-2021-052 Radiation exposure during interventional cardiovascular procedures remains a concern for patients, clinicians and staff. There has been a rapid increase in percutaneous coronary and structural heart interventions, all associated with prolonged radiation exposure times. Interventional cardiologists have the highest occupational radiation exposure and an increased risk of left-sided brain tumours and cataracts has been reported in this group. 1-3 It stands to reason that minimisation of radiation exposure in the catheterisation suite should remain an important focus. The article by van der Merwe in this edition of the journal (page 271) demonstrated that the highest radiation dosage was delivered to the hands of the physician and scrub nurse. A number of minor issues, all preventable, were also identified, emphasising the importance of attention to detail. The damaging effects of radiation exposure can be ascribed to deterministic and stochastic effects. Deterministic effects of radiation are related to the absorbed radiation dose; the severity of deterministic effects is predictable with a dose-related increase in effects and does not occur below a specific threshold. These effects include cataracts, erythema of the skin and sterility. 1 Stochastic effects may occur without a threshold dose and severity of effects is not dose dependent. Stochastic effects include cancers of the skin, thyroid and gastrointestinal tract. 1,3 Taking this into consideration, all efforts should be made to reduce patient and clinician exposure. Patients and personnel All personnel in the catheterisation suite are at increased risk for radiation exposure, and the general perception is that the interventional cardiologist and scrub nurse are at highest risk. However, the anaesthesiologist may also be at risk due to scatter and ineffective shielding. 1,3,4 Both scrub nurses and anaesthesiologists are able to move around but have no control over radiation. This exposure can be decreased by means of good communication and by administering intravenous drugs via extension lines. Radiation should be delayed until medication has been administered and staff requested to move away from the source of radiation. There is an increase in hybrid procedures where the cardiothoracic surgeon may also be exposed and will require protection when close to the radiation source. Paediatric cardiologists may be at higher risk to exposure since they work closer to the source of radiation because of patient somatic size. In adult patients, physicians can work radially or use femoral vascular access, making shielding practically easier. Pregnant staff and patients fall in a special category where known teratogenic radiation effects can occur during early pregnancy. Pregnant patients should be counselled regardless of gestational age, and early pregnancy exposure should be limited to emergency cases when alternative treatment options are not available. The effects of radiation during pregnancy depends on the gestational age, and the foetus is most vulnerable in the first trimester. Low-dose radiation of 0.05 to 0.5 Gy is potentially harmful early in pregnancy but is considered safe later in foetal development. 1 Pregnant staff should avoid the catheterisation laboratory if possible or limit radiation to the absolute minimum. Procedures The difficulty of the procedure and the experience of the cardiologist play an important role in the degree of radiation exposure. The development of structural interventions such as percutaneous valve implantations results in procedures becoming more complex, together with a parallel increase in duration of radiation. Radiation time may be reduced by careful pre-planning and use of supplemental imaging techniques. Additional imaging modalities such as echocardiography and magnetic resonance imaging (MRI) are also evolving and play an important role in preparation and performing difficult procedures. Procedures such as atrial septal defect and patent foramen ovale device closure can be done mainly under transoesophageal echocardiographic guidance with minimal need for radiation exposure. With the increased use of cardiac MRI, radiation of patients may not be indicated if sufficient diagnostic information can be obtained. Actions to reduce radiation exposure Ongoing training on radiation safety should be encouraged to ensure that units comply with the ALARA (as low as reasonably achievable) principles. 2,5 All units should have clear protocols and action plans to protect patients and members of the team against radiation exposure. Staff should be constantly reminded of safety precautions in order to maintain high standards of protection. Reduction in radiation exposure can be divided into active and passive measures. Training of staff remains one of the most important active factors to reduce radiation exposure. Regular training and checklists, especially prior to complex Department of Paediatric Cardiology, University of the Free State, Bloemfontein, South Africa DG Buys, MMed (Paed), Cert Cardiology, DCH (SA), buysdg@ufs.ac.za SC Brown, DMed, FCPaed, DCH (SA)