1. Dose CalibratorQuality Control Alejandro Treto Keiser College

2. A Dose calibrator operation is based on the collection of ions formed as the ionizing radiation passes through the detecting medium (gas). Detecting medium: He, Ar

3. Basic Design of the Gaseous Detector + + +++ + - - - -- -- Gas - If the voltage across the detector electrodes is sufficiently high, ions formed will be collected.

4. A dose calibrator is used to measure samples of radioactivity • Four quality control procedures required for the dose calibrator • Constancy • Linearity • Accuracy • Geometry

5. Constancy • Each day • Long lived radionuclide (Cs 137) 4 1 3 5 7 9 11 13

6. Linearity • At installation • Quarterly • Two methods of measurements • Tc99m vial • Lead attenuation leads

7. Accuracy • Installation and annually • Two sealed reference standards • At least 50uCi ( 200uCi) • At least one with photon energy of 100keV – 500keV

8. Geometry • At installation or whenever a change is made • Performed by increasing volume • 30ml vial – 1mCi of Tc99m in 1ml • 1,4,8,10,15,25

9. Dose Calibrators • Records kept for 3 years including: • model, serial number, date of calibration, results and name of performer • Assurance that activity indicated is close to the truth is fundamental in the administration of radiopharmaceuticals