rescans

Rescans are the act of performing a scan again to obtain new data or verify prior results. A rescan is typically prompted by poor initial quality, changes in the subject, or the need for updated information to inform analysis or decision-making. The aim is to improve accuracy, reliability, or timeliness of the information collected.

In medical imaging, rescans are common for CT, MRI, PET, and ultrasound. They may be ordered to monitor disease progression, guide treatment planning, or verify an incidental finding. Rescans can involve additional radiation exposure or contrast agents and are weighed against patient safety, cost, and resource use. Protocols often include steps to minimize the need for rescans by improving initial image quality.

In document digitization and archival work, rescanning is used when the original scan is blurred, cropped, or otherwise unreadable. Reasons include page misalignment, glare, or physical damage. Adjustments to lighting, resolution, color, or duplex scanning can reduce the need for a follow-up scan; when not sufficient, the item is scanned again.

In information technology and data collection, rescans occur when automatic reads fail or data are ambiguous. Examples include barcode scanning, OCR workflows, or remote sensing where clouds or sensor errors necessitate another pass. Each rescan adds time and cost but can improve data quality.

See also: quality control, data validation, imaging protocol.