# 1เลือกประเภทWhat is the typical source-axis distance for a Co-60 teletherapy machine?60 cm70 cm80 cm90 cm
# 2เลือกประเภทWhich of the following is NOT a component of a Co-60 teletherapy source machine?Radioactive sourcePatient supportGantry and standMicrowave generator
# 3เลือกประเภทWhat material is commonly used in the construction of the collimator for Co-60 machines?LeadAluminumSteelCopper
# 4เลือกประเภทWhich method is most commonly used to control the movement of the Co-60 source?Mercury shutterRotating wheelMoving jawsSource drawer