Data Collection Techniques for Preradioimmunotherapy Imaging

Abstract

Objective: Estimation of absorbed radiation doses to normal organs is essential for use of radiolabeled monoclonal antibodies in cancer therapy. We have developed methods for acquiring gamma camera images that provide precise and reproducible biodistribution data for dosimetry calculations.

Methods: Patient attenuation data is acquired by imaging a radioactive sheet source both with and without the patient between the source and the camera. Organ localization is performed by identifying landmarks on the patient and then injecting ^99mTc agents that visualize the major organs. Using templates placed over the camera positioning scope and point source markers on anatomic landmarks, the patient is positioned for each view and the templates are marked where the sources appear. After radiolabeled antibody infusion the patient is positioned using point source markers and the previously created templates.

Results: We have developed a systematic method which has reduced the amount of time needed for biodistribution data acquisition and processing.

Conclusion: This precise method gives the investigator confidence when comparing pretreatment radiation absorbed dose estimates to the patient post-treatment outcome.