Frank Ellis (radiologist)
Frank Ellis was a British radiologist known for his significant contributions to the field of radiation therapy and the development of tolerance doses for radiation exposure. He is best known for his work in formulating the Nominal Standard Dose (NSD) concept.
Ellis introduced the NSD concept in the late 1960s as a way to quantify the biological effect of fractionated radiation therapy. The NSD aimed to provide a means of comparing different fractionation schedules, considering factors such as the total dose, the number of fractions, and the overall treatment time. It provided a framework for adjusting radiation doses to achieve comparable levels of tumor control and normal tissue damage across different treatment regimens.
While the NSD concept was influential in shaping radiation therapy practice, it also faced criticism due to its limitations and the emergence of more sophisticated models. The NSD equation is:
NSD = D / (N0.24 * T0.11)
Where:
- D is the total dose in rads.
- N is the number of fractions.
- T is the overall treatment time in days.
Despite its simplifications, the NSD provided a valuable tool for clinical decision-making and research in radiation oncology for many years. Ellis's contributions helped to standardize treatment planning and facilitate a better understanding of the effects of radiation on both cancerous and healthy tissues. His work remains a part of the historical development of radiation oncology, even as modern techniques have evolved.