Radiation exposure rises with growing number of computed tomography, nuclear cardiological exams, coronary angiography and fluoroscopy leading to a higher risk of patient overexposure to radiation. It is estimted that 40% of radiation exposure is due to cardiological procedures. Interventional cardiologists and cardiac electrophysiologists are two to three times more exposed to radiation than diagnostic radiolodists. In high volume cath labs the most experienced interventional cardiologists have annual exposure about 5mSv and lifetime exposure increases cancer risk by 1%. There are two main biolgical effects of radiation: tissue reaction (determinstic effects) that becomes evident days or months after exposure and incude skin injuries and cataract, and scholastic effect which is related with potential and future harm damaging DNA or indirectly (free radicals and reactive oxygen specises) leading to cancer manifestation after many years. Increased cancer risk is for doses more than 50mSv. Risk is 3-4 times higher in children than in adults, 38% higher in females than in males, 50% lower in octogenerians than in 50 year-old old patients. Some tissues are more sensitive than others. Highest radiosensitivity organs are breast, colon, lung and stomach.
Patients and doctors protection can reduce the radiation exposure by 90%. Radiation doses in cath lab depend on operator expirience, arterial approach, distance of image intensifier from patient, cine-duration, performing ventriculography or not, projection, magnified views and also some patient characteristcs: BMI, coronary lesion type and sort of arrhythmia to be ablated as maintained and qualitiy controled technology.
In our investigation we compered doses of exposure to patients and operators in 2007 compared with 2009 and found that as we had more experience and awareness of harmful effect of radiation, doses were lower and 2.7% of patients had exposure more than 2Gy and thay are included in the follow up. Doses were similar to other cath labs.
We need more epidemiological, and biodosymetry data on radiological protection in patients (children and adults), interventional cardiologists and staff (including genetic studies), non-cancer effects, innovative devices and procedures. (
| Diagnostic procedure | Effective dose (mSv) | Equivalent number of PA chest radiography each (0.02mSv) | Approximate equivalent period of natural background radiation (years) |
|---|---|---|---|
| Chest X-ray | 0.02 | 1 | 0.008 |
| Coronary angiography | 7 (2-16) | 350 (100-800) | 2.9 |
| Percutaneous coronary intervention | 15 (7-57) | 750 (350-2800) | 6.3 |
| Radiofrequency ablation | 15 (7-57) | 750 (350-2800) | 6.3 |
| Dilatation chronic coronary occlusion | 81 (17-149) | 4050 (850-9600) | 33.7 |
| Aortic valvuloplasty | 39 | 1950 | 16.2 |
| Endovascular thoraco-abdominal aneurism repaire | 76-119 | 3800-5950 | 31.6-49.5 |
| 64-slice coronary CT | 15 (3-32) | 750 (150-1600) | 6.3 |
| Coronary calcium CT | 3 (1-12) | 150 (50-600) | 1.2 |
| Sestamibi stress test (1 day) | 9 | 450 | 3.7 |