Prediction of myelotoxicity using semi-quantitative marrow image scores.
Marrow radiation with resultant myelosuppression is usually dose-limiting in radioimmunotherapy (RIT). This study evaluated the relationship between a semiquantitative score of radiolabeled antibody marrow uptake obtained by imaging and subsequent decrease in peripheral blood cell counts in a patient population in whom marrow malignancy is common.


METHODS
Semiquantitative scores were assigned to lumbar marrow images of 18 patients acquired 0, 6, 24 and 48 hr after the first therapy dose of 131I-Lym-1. Scores were adjusted for injected dose (GBq) and body surface area (m2), and correlated with post-therapy blood counts. A well-defined scale, where 0 and 4 represented least to highest marrow uptake when compared to background, was used to assign marrow image scores. Injected doses of 131I-Lym-1 ranged from 1.1-8.2 GBq (29-222 mCi).


RESULTS
Linear regression of summed marrow scores (0-24 hr after injection) versus decrease in cell counts produced correlation coefficients of 0.76, 0.44, 0.58 and 0.46 for platelets, granulocytes, white blood cells (WBC) and hematocrit, respectively. Scores for individual and other combinations of images obtained immediately up to 24 hr after injection were also predictive.
Lim
S
S
University of California Davis Medical Center; and Veterans Administration Northern California Health Care System, Sacramento 95816, USA.
DeNardo
G L
GL
DeNardo
D A
DA
O'Donnell
R T
RT
Yuan
A
A
DeNardo
S J
SJ
D001772:Blood Cell Count / Q000528:radiation effects; D001853:Bone Marrow / Q000000981:diagnostic imaging* / Q000528:radiation effects*; D004307:Dose-Response Relationship, Radiation; D005240:Feasibility Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000009:adverse effects / Q000627:therapeutic use; D016014:Linear Models; D016499:Radioimmunotherapy / Q000009:adverse effects*; D011877:Radionuclide Imaging; D011879:Radiotherapy Dosage; D013997:Time Factors
D007457:Iodine Radioisotopes