Cluster 149: lesion measurable irradiated recist disease previously radiation cm mm index Cluster 160: lesions target measurable patients bone cm irradiated disease radiation tumor Cluster 760: target designated irradiated field persistence lesions confirm tumors assess progression Cluster 1472: target lesion measurable recist disease criteria lesions radiation response tumor Cluster 2134: measurable neuroblastoma lesions mibg disease fluid detected gallium bone collections