When IMPAX receives images with SOP Instance UIDs that already exist in its database, the following happens:
If the study ID of the new images does not already exist in IMPAX, IMPAX accepts the new images, assigns a new SOP Instance UID to the new images, and records the reassignment in the dosr_uid_mapping table.
If the study ID of the new images already exists in IMPAX, IMPAX considers them to be the same images and, by default, rejects these new images. IMPAX can be configured to accept the duplicate images; however, we do not recommend this. Instead, if appropriate, we recommend configuring IMPAX to send an error message to the modality to alert the modality technician that the duplicate images have been rejected in IMPAX.
 | Note: If you suspect studies with potential SOP Instance UID conflicts exist, to find any reassignment records, query the dosr_uid_mapping table by study_ref. |
Conditions under which a new SOP Instance UID is generated
The following illustrates a workflow that causes IMPAX to generate a new SOP instance UID:
The technician sends an image to IMPAX with a SOP Instance UID of 1.2.3.4 that belongs to study accession number AAA111.
The technician realizes that the image actually belongs to another study with a study accession number of BBB222 and sends another copy of the same image (SOP Instance UID 1.2.3.4), under the correct accession number (BBB222) to IMPAX.
IMPAX recognizes that the SOP Instance UID already exists in its database, but because the study accession number is new, IMPAX reassigns the image’s SOP Instance UID to 5.6.7.8.
The image exists twice in IMPAX: Once under accession number AAA111 with SOP Instance UID 1.2.3.4 and once under accession number BBB222 with SOP Instance UID 5.6.7.8
 | CAUTION! Correcting the study information and resending the images does not remove the incorrectly identified images from IMPAX. When a new SOP Instance UID is assigned, the previous copy of the image is not deleted; it still exists in IMPAX under an incorrect accession number. To prevent misdiagnosis, modality technicians must ensure that incorrectly identified images are deleted from IMPAX as soon as possible. |