Founder of Human Radiobiology

A Historical Vignette by Judith Marinelli Godfrey

Leonidas D. Marinelli founded the field of Human Radiobiology by investigating individuals exposed to nuclear explosions and radium in medicine and industry. He pioneered long term effects of radium in humans exposed 29-years, developed the Whole Body Counter that directly detected the low-level gamma-ray radiations an individual emitted, and the sensitive low-level gamma-ray scintillation crystal spectrometry that quantified the total content of natural potassium (K-40) in the human body.

Today, a personalized dose of radioactive iodine for thyroid cancer is determined by the principles of internal dosimetry set forth by Marinelli in 1942. He extended radioactive iodine to treat thyroid cancer metastases in 1946.  He discovered radium in thorium-contaminated people in 1956 and extended studies worldwide for definitive evidence for radium-induced cancer and leukemia. We may attribute our comprehensive understanding of  anthropological effects of radiation to  Marinelli.

The first low-level gamma-ray detector for hospital use was the “twin crystal scintillator” spectrometer, developed from the dosimetry and spectrometry of the Whole Body Counter he invented in 1950. The whole-body scanner was copied around the world and developed into the spectacular medical imaging we depend on today.¹