In medical field, X-rays and radioactivity have been used for diagnostic and therapeuticpurposes for over the years. The benefits of ionising radiation are unquetionable. Since ionizing radiationis also induced biological effect to human, radiation protection standards is required. Radiation safetycan be achieved by education, training, quality control, proper equipment, design facilities, andregulations. Actually workers and public will involve with low radiation doses and will not hazardous ifknowledgeable and responsible persons perform activities with ionizing radiation. Exception is present inmedical field. Interventional radiology procedures using fluoroscopy for guiding catheter will potentiallydeliver high doses to workers and patients. For example, cardiac catheterization procedure can producesevere radiation injury to patient's skin. It is also reported the result of prelimenary study on patiententrance surface dose and dose equivalent recieved by team members of cardiac catheterization. Thisstudy is performed by the collaboration between UI-BATAN. The results indicated that the working areaof cardiac catheterization was categorized as supervised area.Key words :ionizing radiation, low radiation dose, interventional radiology, cardiac catheterization.