FIGURE 1. Intercomparison results for ⁹⁰Y. First letter in laboratory code represents instrument brand (V, Veenstra; I, Isomed; A, Atomlab). Laboratory codes without decimal points represent laboratories with only 1 instrument. Laboratory codes with decimal points represent laboratories with different instruments. Dotted lines represent an arbitrary tolerance of ±20%. A_meas/A_ref [–] = ratio of measured activity to reference activity.