Query: When was my last imaging study and what was it for?, FHIR Resource: {'resourceType': 'Observation', 'status': 'final', 'category': [{'coding': [{'system': 'http://terminology.hl7.org/CodeSystem/observation-category', 'code': 'laboratory', 'display': 'Laboratory'}]}], 'code': {'coding': [{'system': 'http://loinc.org', 'code': '1975-2', 'display': 'Bilirubin.total [Mass/volume] in Serum or Plasma'}], 'text': 'Bilirubin.total [Mass/volume] in Serum or Plasma'}, 'subject': {'reference': 'urn:uuid:60abc6f7-093a-6a59-8512-7cadf7e16bee'}, 'effectiveDateTime': '2016-12-31T04:52:06+05:30', 'valueQuantity': {'value': 9.0655, 'unit': 'mg/dL', 'system': 'http://unitsofmeasure.org', 'code': 'mg/dL'}, 'interpretation': None}