A professional who measures and calculates radiation dose and develops optimum arrangement of radiation fields and exposures to treat patient. Responsibilities include:

• Studies prescription, x rays showing area to be treated, and requirements for dose calculation.
• Selects beam energy, optimum multiple beam arrangement, beam modifying devices, and other factors, using computer, manuals, and guides.
• Develops several possible treatment arrangements that meet physician's criteria and submits arrangements for selection by physician.
• Measures and calculates prescribed radiation dose based upon field sizes, depth of tumor, treatment unit, beam modifying devices, and other information, using manuals, guides, and computer.
• Calculates and records daily prescribed radiation dose.
• Explains treatment plan to radiation-therapy technologists .
• May operate x-ray equipment to obtain diagnostic x ray of patient in treatment position.
• May simulate treatment procedure to assist in planning treatment.