Radiation Therapy Exam Real Questions And Answers | Verified

Radiation Therapy Exam Real Questions And Answers | Verified The ALARA principle applies for - Answer- Occupational workers, patients, visitors end members of general public The filter in a flim badge is made of - Answer- Copper and Aluminun Occupational workers may not receive more than__________to their hands - Answer- 25 mrem/quarter The formula for dose equivalent in Sieverts (SV) is: - Answer- Dose Eq. (SV) = dose [Gy] x Q One rem is equal to - Answer- .01 Sv Linear Energy Transfer is defined as - Answer- Energy absorbed per path length of ionizing particle When space is not a problem, the choice of shielding material for megavoltage rooms is: - Answer- Concrete Is _____considered an example of a non-stochastic radiation effect - Answer- Lens opacification The two types of microwave power sources used in linear accelerators today are - Answer- Klystrons and Magnetrons As compared to kilovoltage x-ray, which of the following statements are considered advantages of megavoltage therapy? - Answer- Skin sparing & Less lateral scatter The type of target found in a linear accelerator is called a - Answer- Transmission target When using a thoraeus filter, the _____ layer must always be nearest the patient - Answer- Aluminum When the light over the treatment room door is on it signifies - Answer- The radiation beam is on One of the daily checks on linear accelerators is to check the vacuum of the waveguide. Normally, the reading is - Answer- 0 (zero) To clear a MODE FAULT, you must press the - Answer- Beam off/reset button The hazard associated with the operation of a linear accelerator that could cause retinal eye damage is - Answer- Laser beams Which of the following factors must be known in order to calibrate a megavoltage - Answer- Treatment room temperature Barometric pressure Standard calibration factor for ion chamber The depth in a phantom that is recommended for the calibration of a high energy [4-15MV] linear accelerator is - Answer- Dmax The name of the radiation instrument that would best be used to locate an iridium seed which fell on the floor is - Answer- Geiger-Muller Counter Which of the following situations is the most likely reason that the light field and the radiation field do not coincide - Answer- Range finder light needs adjustment Following repairs to the linear accelerator's field/distance light assembly, which of the following checks must be performed prior to resuming treatments? - Answer- SSD/SAD readouts & Light field/radiation field coincidence While treating a patient using a rotational technique, the gantry rotates past the stop point. This is most likely a malfunction of the - Answer- Limit switch Which of the following parameters must be provided in order to determine the monitor units per degree for an arc rotation treatment - Answer- Number of cGys per treatment & Degrees in rotation In order to check the centering of isocentric units, a film is placed to approximate the central ray with exposures being made at the nine gantry positions spaced ____ apart - Answer- 40 degrees Calculate the BOT to treat AP/PA fields at midplane. Patient separation is 10 cm, PDD is 72%. OPF is 1.03 r/mu and dose rate in air is 1.00 r/mu. Blocking tray absorbs 3% of beam daily dose is 250 cGy. - Answer- 173.6 =174 An incorrect rotation of the machine or patient could cause - Answer- 1. Missing part of the tumor 2. Irradiating healthy soft tissue unnecessarily 3. Irradiating a vital organ unnecessarily