Term
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Definition
| International Commission on Radiation units and measurement |
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Term
| Order of volume definitions? |
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Definition
GTV
CTV
PTV
treated volume
irradiated volume |
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Term
| The gross palpable or visible/demonstratable extent and location of malignant growth. |
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Definition
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Term
| A tissue volume that contains a demonstrable GTV and/or subclinical microscopic malignant disease, which has to be eliminated. This volume has to be treated adequately in order to achieve the aim of therapy, cure or palliation. |
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Definition
| CTV clinical target volume. |
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Term
| A geometrical concept, and it is designed to select appropriate beam sizes, and beam arrangements taking into consideration the net effect of all the possible geometrical variations in order to ensure that the prescribed dose is actually absorbed in the CTV. |
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Definition
| Planning target volume PTV |
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Term
| What must be known before determining treatment strategy? |
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Definition
| Know where all disease and probable disease is. |
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Term
| Defined to select appropriate beam sizes and beam arrangements, taking into consideration all possible geometrical variations and innaccuracies in beam and patient set up. |
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Definition
| PTV planning target volume |
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Term
the volume enclosed by an isodose surface, selected and specified by the radation oncologist as being appropriate to achieve the purpose of treatment
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Definition
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Term
| tissue volume which receives a dose that is considered significant in relation to normal tissue tolerance. |
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Definition
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Term
| who makes decisions about appropriate course of decision |
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Definition
| rad oncologist and patient. |
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Term
| goal of 'definitive/cure' |
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Definition
| To cure patient of cancer |
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Term
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Definition
| to relieve pain and suffering, possible prolong life. |
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Term
| provides treatment prescription |
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Definition
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Term
... considers effect of treatment on normal tissue and organs in the path of the beam.
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Definition
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Term
| region of demonstrated tumor and any tissue with presumed tumor cells |
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Definition
| treatment site... found on the prescription |
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Term
| 5 things on prescription: |
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Definition
treatment site
intended total tumor dose
number of treatments
dose per treatment
frequency of treatment
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Term
| equation for number of treatment..? |
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Definition
| total dose/ dose per fractions |
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Term
| in treatment planning ... ________ used to define treatment volume. |
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Definition
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Term
| 4 methods that are used for localization: |
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Definition
palpation
radiography
imaging
direct visualization |
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Term
| to physically feel for tumor |
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Definition
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Term
| CT, MRI, Mammo, etc. are all used.. |
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Definition
| as radiography techniques in tumor localization |
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Term
| after simulation and all details of treatment plan are complete,... |
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Definition
physics staff determines dose calculations.
Patient is scheduled for first day of radiation treatment. |
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Term
| = After complete course of radiation therapy, the patient has periodic evaluations with their oncologist. number of visits depends on type of cancer, dose, and overall results. |
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Definition
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Term
| ____ is measured at a specific point in the medium and the energy deposited. |
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Definition
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Term
| distance beneath skins surface where dose is to be delivered. |
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Definition
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Term
| in _____, use patient midline to calculate depth. |
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Definition
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Term
| _________ - use isocenter or intersection of the beams to calculate depth. |
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Definition
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Term
measurement of patient thickness from point of beam entry to point of beam exit |
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Definition
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Term
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Definition
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Term
| distance from source to surface of patient |
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Definition
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Term
| SSD usually measured using... |
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Definition
| ODI optical distance indicator |
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Term
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Definition
SAD - d
d = depth of isocenter
sad= source- axis distance |
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Term
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Definition
intersection of the axis of rotation of gantry and axis of rotation of collimator for treatment unit.
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Term
| in SAD, or isocentric technique, ___ changes and ____ stays the same as beam rotates. |
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Definition
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Term
| ____= physical size set on collimators of therapy unit that determines size of treatment field at a specific distance. |
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Definition
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Term
| field size will change with distance from source because |
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Definition
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Term
| ____ = field size set at collimator is same as that measured on pt. skin |
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Definition
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Term
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Definition
depth of maximum equillibrium
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Term
| depth at which electron equilibrium occurs for photon beams = |
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Definition
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Term
| this locates the maximum absorbed dose that occurs for a single field beam. |
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Definition
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Term
| as energy decreases, dmax... |
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Definition
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Definition
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Definition
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Definition
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Definition
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Definition
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Definition
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Definition
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Term
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Definition
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Term
| for _______________, dose at Dmax should be calculated and recorded. |
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Definition
| POP and single field treaments. |
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Term
| in POP and single field, Dmax will be |
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Definition
| higher than prescribed dose. |
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Term
| In multiple field arrangements with megavoltage.. dose at Dmax is |
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Definition
| usually less than prescribed dose |
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Term
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Definition
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Term
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Definition
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Term
| Output is affected by : (3) |
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Definition
field size
distance
atomic number of the attenuating medium (basically its density) |
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Term
| ratio of dose rate of a given field size to dose rate of a reference field size = |
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Definition
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Term
| allows for change in scatter as collimator size changes. |
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Definition
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Term
| output factor is normalized or referenced to... |
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Definition
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Term
| ________ field size = increase output factor OF |
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Definition
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Term
| accounts for dose rate changes at new distance |
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Definition
| field size correction factor |
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Term
| formula for field size correction factor |
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Definition
dose at Dmax for field size
dose at Dmax for standard field size |
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Term
| if the dose rate is 1.0 cGy/mu at 100 cm, then what is the dose at 125 cm? |
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Definition
x/1= 100^2/125^2
inverse square law |
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Term
| formula for equivalent square |
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Definition
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Term
| PDD is used when ____ is involved. |
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Definition
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Term
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Definition
| collimator/ and open or unblocked field size |
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Term
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Definition
| patient/phantom or Blocked EFS |
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Term
| when blocks are used, you must find... |
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Definition
| blocked field size or effective field size |
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Term
| This is the equivalent rectangular field dimensions of the treated area with the collimator dimension |
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Definition
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Term
| EFS is usually larger/smaller than collimated field size. |
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Definition
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Term
| As radiation beams travel throught the body, it gives up energy. . . the more tissue, the more |
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Definition
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Term
| 4 things to measure attenuation |
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Definition
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Term
| attenuation will be affected by |
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Definition
| energy, scatter, and beam geometry |
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Term
| what are the 3 SAD techniques? |
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Definition
TAR tissue air ratio
TPR tissue phantom ratio
TMR tissue maximum ratio |
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Term
| ratio of absorbed dose at a given depth to absorbed dose at a fixed reference depth.(usually Dmax) |
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Definition
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Term
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Definition
absorbed dose at depth.. x 100
absorbed dose at Dmax |
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Term
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Definition
energy
field size
SSD
depth |
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Term
| as depth increases.. pdd ? |
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Definition
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Term
| as you increase energy, PDD ? |
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Definition
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Term
| as you increase field size, PDD ? |
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Definition
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Term
| As you increase SSD, you have to _______ PDD |
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Definition
| increase, because PDD decreases as you get further away. |
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Term
| ratio of absorbed dose at a given depth in a phantom to the absorbed dose at the same point in free space. |
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Definition
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Term
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Definition
dose in tissue
dose in air |
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Term
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Definition
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Term
| TAR is used for calculations of |
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Definition
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Term
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Definition
| similar. at Dmax they are the same, but TAR can be used at any depth. |
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