The Usefulness of High Dose (7-10mci) Gallium (67Ga) Scanning to Diagnose Richter's Transformation

Gallium (⁶⁷Ga) scan was performed in 29 CLL patients with chronic lymphocytic leukemia who were suspected on clinical grounds to have Richter's transformation (RT). Of 29 patients, nine had a positive ⁶⁷Ga scan; seven of these had a subsequent biopsy that verified large-cell lymphoma or Hodgkin's disease. The other two patients underwent biopsies that revealed fungal infections, a known cause of ⁶⁷Ga uptake. Two patients had biopsies that were consistent with RT but showed no affinity to ⁶⁷Ga. One false negative resulted five days after chemotherapy, a known cause of diminished ⁶⁷Ga uptake. The other occurred within a small infraorbital mass, containing onl 10% centroblasts, which is below the level of detection for ⁶⁷Ga scanning. Subsequent ⁶⁷Ga scans in both patients revealed ⁶⁷Ga avid lesions, which demonstrated RT upon biopsy. This technique was more strongly predictive of RT than was measurement of serum B-2 microglobulin or serum lactate dehydrogenase levels.⁶⁷Ga scanning is very useful in localizing an optimal site for biopsy to document RT; it may also have the potential to help assess response to treatment, predict recurrence, and contribute to long-term follow-up in this subset of patients.