FIGURE 3. Neck scans for patient P6 at 48 h during diagnostic course 1 (A), diagnostic course 2 (B), and therapy (C). For the therapy scan, the gray scale was adjusted to the diagnostic activity. The increased number of counts in the upper left corner in panels A and B is an artifact caused by septal penetration of the photons emitted by the ¹³³Ba quality control phantom, which was scanned together with the patient.