**3. Image-guided interventions**

Interventional radiology is a newly emerged branch from radiology using fluoroscopic guidance to perform complex procedure noninvasively. Nowadays, many imaging modalities are used in the field of image-guided interventions. These imaging technologies include, in addition to planar fluoroscopy, CT, MRI, and ultrasound. The image-guided intervention techniques expanded rapidly due to its numerous advantages including local anesthesia and low rate of mortality and morbidity (short stay at hospital).

#### **3.1. Fluoroscopy**

Fluoroscopy, or real-time imaging, is an imaging technique that produces dynamic images at low tube current range from 0.5 to 5.0 mA for longtime intervals, resulting in dynamic images with lesser image quality. The fluoroscopy played a fundamental role in emergence of interventional radiology since its introduction by Thomas Edison (1847–1931) in May, 1896, just an year after the discovery of X-rays. The early fluoroscope composed of fluorescent screen (zinc-cadmium sulfide) placed over the patient's body between the patient and radiologist (**Figure 3**) at complete darkness, and the radiologist looked directly at the screen. Dark adaptation was required from 10 to 30 minutes by wearing red goggles to enhance viewing.
