<qa>  How many subjects ingested calcium supplements after a spine DXA scan?We hypothesized that ingesting calcium tablets prior to a spine bone density scan will not affect the bone mineral density as measured by DXA. To test this, 36 subjects ingested various calcium supplements after a spine DXA scan and were then scanned again 15, 30 and 45 minutes after ingestion. Subsequently a subset of 15 subjects had three spine scans performed for instrument precision and subsequently ingested a calcium tablet with scans 15 and 30 minute intervals after ingestion. 