Need to know questions and a few more

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Need to know questions and a few more
2014-02-16 14:13:13
Candice Need know questions few more

Need to know questions and a few more
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  1. What is TD 5/5 mean
    Tissue dose associated with a 5% injury rate within 5 years
  2. What is the TD5/5 of the lens
    500 cGy
  3. What is the TD5/5 of the kidney
    2000 cGy
  4. What is the TD5/5 of the heart
    4500 cGy
  5. What is the TD5/5 of the Spinal cord
    4500 cGy
  6. What is the TD5/5 of the intestines
    4500 cGy
  7. What is the TD5/5 of the bladder
    6000 cGy
  8. What is the TD5/5 of the rectum
    6000 cGy
  9. What is the TD5/5 of the salivary gland
    5000 cGy
  10. What does LD 50/30 mean
    • lethal dose of 50% of population in 30 days.
    • The dose of radiation expected to cause death of 50% of the exposed population  in 30 days
  11. The abdomen is defined as the portion of the body that lies between the _____and the ______ and that contains the_______
    • thorax
    • pelvis
    • peritoneal cavity
  12. Generally speaking, the kidney tolerance to irradiation in an adult is _____ delivered at ___-____per fx
    • 2000 cGy
    • 180-200 cGy
  13. The most common site of pancreatic tumors is in the ____
    in the head of the pancreas
  14. ____ _____ is a tumor originating in the kidneys
    Wilms' tumor
  15. Where do Neuroblastoma tumors originate most often
    sympathetic nervous system.
  16. When pelvic irradiation is delivered in an obese patient in the supine position, the concern is that
    uncertainty of dose due to variations in patient thickness would be caused when attempts were made to eliminate skin folds.
  17. To reduce the volume of small bowel within a pelvic field, the patient's position should be
    prone on a belly board
  18. The primary purpose of a testicular shield is to
    reduce the amt of internal scattered dose in the testes
  19. Of GYN tumors treated with radiation therapy, the most common is
    squamous cell carcinoma of the cervix
  20. The most common position for patients receiving total skin electron irradiation is
    standing with legs spread and arms raised
  21. The main goal of radiation therapy in patients with bone mets is to
    prevent fractures and reduce pain
  22. In patients treated for spinal cord compression, the treatment field should include approximately
    2 vertebral bodies in each direction beyond the demonstratable disease
  23. Three 10 MV beams are equally weighted at the isocenter in the illustration. The dose variation across the target area could be reduced by doing which of the following?
    1) reducing the weight of the beam
    2) angling the lateral beams anteriorly by 10 degrees
    3) increasing the wedge angle of the lateral beams
    4) reducing the weight of the lateral beams
    1 and 3
  24. What is DICOM
    DICOM, stands for digital imaging and communication in medicine and is a document which defines a method of communication that makes it possible to communicate remotely through a network or media by ensuring compatibility of the equipment by eliminating proprietary formats
  25. CT/MRI/PET???
    A CT helps us with planning and brings us 3rd dimension. It is composed of a matrix of pixels (2D) and each pixel represents a volume of tissue or slice thickness (3D). CT scanners use xrays and patients are irradiated with an xray beam with a distribution of approx., 20-140 keV. The CT shows delineation of bony pathology better than an MRI. The MRI is better at showing soft tissue but instead of using xrays, an MRI using a strong magnetic field and we generally use the MRI to fuse with the CT so that we get a clearer picture of the bones along with the soft tissue. We also can use the PET CT which is technique used to image the chemical or physiological processes in the body. Patient is given an imaging agent called FDG, fluoro-2-deoxy-D-glucose about an hour before the scan. This imaging agent will race to any processes in the body with high metabolic activity and cancer cells use glucose at much higher rates than normal cells which is why the cancer cells will show up very brightly on the scan.
  26. An off axis point is any point not on the ____________. The off axis point is used as a __________ point to tell the Dr what the dosage and effect on the tissue at that point will be as well as to find the __________.
      • any point not on the CENTRAL AXIS
      • CALCULATION point
      • Off Axis Ratio (OAR)
  27. A brain patient is treated midplane on the 6 MV linac. The separation is 16. The fs is 15X15 cm. The script states that a dose of 3000 cGy is to be delivered. Calculate the MU and use the data table she gave us in class
    • 163 MU
    • 150/8.57/1.071= 163 Mu each side
  28. 600 for a fraction. Weight the beam if we have
    a right lateral, left lateral, and an AP, (30%, 20% and 50% respectively
    • rt lat would be 180
    • lt lat would be 120
    • Ap would be 300
  29. Prone PA spine depth of 5 at 250 cGy, field size is 15x15. use data table from class
    250/.876/1.038= 275 MU

    I have in my notes that we use the SSD technique for single open fields like the spine?

  30. Calculate MU for a 2fd wedged R parotid equally weighted. FD1 Gantry angle 330, FD2 Gantry angle of 210. FS 1 is 5X11 and fs2 5x9.
    WF 15;.998, WF30;.948, wf45;.930 and 60;.920
    RAO 95 SSD
    RPO 90 SSD
    TF .969
    • RAO is 107 MU and RPO is 131 MU
    • Start with setting up each field and splitting the dose 180/2=90
    • draw out the gantry angle to find the hinge angle. 330-360=30 and 210-360=150, subtract the 150-30=120 so use the 180-120/2=60/2= 30 wedge
    • Now find the equivalent square of each field, which would be a 7x7 and a 6X6
    • Because the field sizes are not easily found on the chart, you can either guestimate or interpolate and I came up with 5X5 and a 10X10. Then find the output factor and figure as usual
  31. The 10 year survival for patients with ALL stages of Hodgkin's disease is approx
  32. The patient position for treatments of a mantle field in Hodgkin's disease is usually
    supine with the chin extended and arms above the head
  33. It is always important to align the patient with the _____ laser alignment line everyday because if it is not, the field is rotated with respect to the patient's body
  34. Tattoos made on the patient's skin indicating irradiated areas can shift due to
    growth and weight changes
  35. The advantage of intraoperative radiation therapy is that is provides
    superior normal tissue sparing and improved precision.
  36. High and low dose TBI is used in the protection of patients for a ___ ____ ____ and in the treatment of
    • bone marrow transplant
    • CLL, chronic lymphocytic leukemia
  37. What is the most common intracranial tumor?
    metastatic disease from a primary tumor
  38. What do ARRT, and RT stand for
    • American Registry of Radiologic Technologist
    • Registered Technologist (Radiation Therapy)
  39. Label this structure
    • 1. Right lobe of liver
    • 2. Left lobe of liver
    • 3. esophagus
    • 4. stomach
    • 5. duodenum
    • 6. gall bladder
    • 7. Right kidney
    • 8. Left kidney
    • 9. Right adrenal gland
    • 10. Left adrenal gland
    • 11.pancreas
    • 12 hepatic duct
    • 13. Common bile duct
    • 14. pancreatic duct
    • 15. ampulla of Vater (Vater is capitalized)
    • 16. spleen
    • 17. Right ureter
    • 18. Left ureter
  40. Don't forget pic on page 464