Systems and methods for dispensing radioactive liquids

An apparatus for dispensing radioactive liquids, the apparatus comprising:

• a support arm rotatable about a rotation axis;
• an actuator operatively connected to the support arm, the actuator including a second stepper motor and a third stepper motor, the second stepper motor operatively connected to the support arm and configured to rotate the support arm about the rotation axis, the third stepper motor operatively connected to the support arm and configured to displace the support arm in a direction parallel to the rotation axis;
• and
• a pipette assembly mounted to the support arm, the pipette assembly including a pipette tip defining an opening through which liquids are aspirated and dispensed, a piston, and a first stepper motor operatively connected to the piston to control linear displacement of the piston;
• wherein the apparatus is free of radiation-sensitive electronics.

A method of dispensing radioactive liquid using a dispensing apparatus including a pipette assembly mounted on a rotatable support arm, the pipette assembly including a pipette tip, a piston, a controller, and a stepper motor operatively connected to the piston, the method comprising:

• positioning the pipette assembly above a first vial using the support arm;
• aspirating a volume of radioactive liquid from a first vial by displacing the piston in a first direction using the stepper motor;
• determining, using the controller, a number of steps by which to rotate the stepper motor based on a non-linear relationship between a volume of liquid aspirated or dispensed by the pipette assembly and a corresponding number of steps by which the stepper motor is rotated;
• rotating the support arm to position the pipette assembly above a second vial;
• and
• dispensing at least a portion of the volume of radioactive liquid into the second vial by displacing the piston in a second direction opposite the first direction using the stepper motor.