Chapter 1: Fluoroscopy in Interventional Pain Medicine

INTRODUCTION

Since their discovery in 1895, x-rays have revolutionized the practice of medicine. By allowing doctors to view the inside of the living body, x-rays have greatly increased our ability to diagnose and treat disease and to precisely deliver targeted therapies. The fluoroscope was the first x-ray machine and has evolved from its humble beginnings into a powerful and sophisticated device that has become the basis for the new field of interventional pain management. Modern fluoroscopes enable the interventional pain practitioner to use continuous, real-time x-ray imaging to guide interventional procedures that target the physical generators of pain with a high degree of precision and safety. Since fluoroscopy is essential for most invasive pain procedures, it is imperative that interventional pain physicians have a firm understanding of the fluoroscope in order to use it safely and effectively in daily practice.

HIGHLIGHTS IN THE HISTORY OF FLUOROSCOPY

• 1895: German physicist Wilhelm Roentgen discovers x-rays and takes the first fluoroscopic image, purportedly of his wife’s hand, winning the 1903 Nobel Prize in Physics for his efforts.

• 1896: Thomas Edison invents the first fluoroscope, which is quickly adopted for medical uses.

• 1897: Madame Curie discovers radium, which is then used to illuminate games of chance in New York City.

• 1898: The inappropriate, nonmedical use of fluoroscopy becomes increasingly common.

• 1899: Compensation is awarded in the first medical malpractice suit involving x-ray injury.

• 1900: Radiation injuries become increasingly common, and practitioners become increasingly aware of the dangers of x-ray exposure.

• 1910: After several years of practice, radiology pioneer Dr. Mihran Kassabian suffers severe radiation burns to his hands and ultimately dies of radiation-induced cancer at age 34.

• 1929: The National Council on Radiation Protection and Measurement (NCRP) is created to protect patients, healthcare workers, and the public from the harmful effects of radiation.

• 1994: Patient injuries resulting from excessive use of fluoroscopy during medical procedures prompt the FDA to issue a Public Health Advisory.¹

THE PHYSICS OF X-RAYS

X-rays are a form of ionizing radiation that can be created in the fluoroscope and harnessed for medical imaging. X-rays are produced in the x-ray tube of the fluoroscope, which contains a cathode and metal anode.

• When high-velocity electrons leave the cathode and collide with the metal anode, the kinetic energy contained within the electrons is converted to electromagnetic energy and released in the form of x-rays.

• X-rays are close to light photons on the electromagnetic spectrum but have shorter wavelength and higher energy (Figure 1-1).

The x-rays produced by the x-ray tube are directed through body tissues. When these x-rays contact matter, they interact in one of three ways: