E2821. In Real Time: The Physics of Fluoroscopy
  1. Stephanie Jankovic; Oregon Health and Science University
  2. Marc Michael Lim; Oregon Health and Science University
Fluoroscopy is a mainstay in both diagnostic and interventional radiology, with the principles of fluoroscopic image acquisition forming the basis of radiography and digital subtraction angiography (DSA). Understanding the physics of fluoroscopic image generation is key to optimizing image acquisition while maintaining dose reduction.

Educational Goals / Teaching Points
Understand the physics of fluoroscopic image generation to optimize image acquisition and dose reduction. Review the history of x-rays, and the transition from, and differences in, film and digital detectors. Understand how fluoroscopic dose is calculated, and the methods that allow diagnostic and interventional radiologists to adjust those factors in real-time to follow as low as reasonably achievable (ALARA) principles. Review radiation safety.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Traditional image intensifiers and flat panel detectors are engineered differently, resulting in unique artifacts, troubleshooting, and factors affecting dose. Modes of operation in fluoroscopy including continuous fluoroscopy, pulsed fluoroscopy, frame averaging, digital spot filming, last Image hold/radiationless collimation adjustment, roadmapping, high-level dose rate fluoroscopy (HLF), and cone-beam CT (rotational angiography). Skin dose including effects, entrance skin exposure (ESE) rate limits, determinants and Air kerma.

An in depth understanding of the physics of fluoroscopic imaging generation and acquisition allows for optimal image quality while utilizing the lowest radiation dose to ensure high quality, diagnostic imaging in the safest manner for the patient. Multiple techniques, especially with the advancements made in the digital age of imaging, can be utilized to significantly reduce radiation dose and improve radiation safety for both the radiologist and the patient.