i.e. a clinically valuable marker of treatment response, and this is most clearly established in the form of diagnostic imaging employed in the study.
Reduction in viable tumour tissue may be a temporary phenomenon and the tumour may start to grow again. Optimality refers to judging a reduction in Standardized uptake values (SUV) as early as possible with sufficient precision and is based on Schedule Optimizing (SO) studies. More flexible schedules may be required to account for individual variation given the patient population(s) – based on tumour characteristics, type of treatment, etc., and with some sub-populations having rapidly & others slowly progressing cancers. (i.e. use a population kinetics approach)