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- TCIA Dates: dates (be they birthdates, imaging study dates, etc.) in the DICOM headers of TCIA radiology images have been discounted offset by a random number of days. The discount offset is a number of days between 3 and 10 years prior to the real date that is consistent for each TCIA image-submitting site and collection but that varies among sites and among collections from the same site. Thus, it is possible to figure the number of days between between a subject’s longitudinal imaging studies are accurately preserved when more than one study has been archived within a site-collection. These random numbers are not known to TCIA image consumerswhile still meeting HIPAA requirements.
- TCGA Dates: the patient demographic and clinical event dates are all the number of days from the index date, which is the actual date of pathologic Dx. So all the dates in the data are relative negative or positive integers, except for the “days_to_pathologic_diagnosis” value, which is 0 – the index date. The years of birth and Dx are maintained in the distributed clinical data file. The NCI retains a copy of the data with complete dates, but those data are not made available.With regard to other TCGA dates, if a date comes from a HIPAA “covered entity’s” medical record, it is turned into the relative day count from the index date. Dates like the date TCGA received the specimen or when the TCGA case report form was filled out are not such covered dates, and they will appear as real dates (month, day, year).
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