I intend to do an update based on join, but getting an error. What is missing?

update
     vna.patients,
     vna.patient_observations,
     vna.studies,
     vna.series,
     vna.instances,
     vna.sop_classes,
     vna.files,
     vna.modalities,
     vna.issuers
join patient_observations on atients.patient_id=patient_observations.patient_id 
join studies
  on  patient_observations.study_id=studies.study_id
  AND studies.patient_id=patients.patient_id
join series
  on series.study_id=studies.study_id
join instances
  on instances.series_id=series.series_id
join sop_classes
  on sop_classes.sop_class_id=instances.sop_class_id
join files
  on files.instance_id=instances.instance_id
left join modalities
  on modalities.modality_id=series.modality_id
left join issuers
  on (patients.issuer_of_patient_identifier=issuers.issuer_id)
set PATIENT_NAME='AAPM'
WHERE PATIENT_IDENTIFIER='TG18-2002';

ERROR 1066 (42000): Not unique table/alias: 'patient_observations'