Radiation pneumonitis (RP) can be an adverse complication of radiotherapy and usually occurs as an acute reaction from 6 to 12 weeks after radiotherapy. FDG PET is described as an early and adequate barometer for RP diagnosis. Only 1 case of fluoroestradiol uptake contemporary of metabolic FDG changes attributed to RP is reported. We report a case of a breast cancer patient with asymptomatic RP, who at 1 year later, at sequelar stage on CT, showed long-term memory of RP by F-fluoroestradiol PET imaging with nonmetabolic FDG PET.