Section 35.60 - Possession, use, and calibration of instruments used to measure the activity of unsealed byproduct material(a) For direct measurements performed in accordance with § 35.63 , a licensee shall possess and use instrumentation to measure the activity of unsealed byproduct material before it is administered to each patient or human research subject.(b) A licensee shall calibrate the instrumentation required in paragraph (a) of this section in accordance with nationally recognized standards or the manufacturer's instructions.(c) A licensee shall retain a record of each instrument calibration required by this section in accordance with § 35.2060 .