Modern photon beam radiotherapy is carried out with a variety of beam energies and field sizes under one of two set-up conventions: a constant source to surface distance (SSD) for all beams or an isocentric set-up with a constant source to axis distance (SAD).
what is FSD in radiotherapy?
[*A frequently used alternative term for the ‘focus to skin distance’ ( FSD ) is the ‘source to skin distance’ ( SSD ).] 4.4. Manual calculation of the ‘depth dose’ The radiation dose that is prescribed by the oncologist is the dose to the point of treatment.
what is source to axis distance?
The source–axis distance (SAD) is a treatment machine design parameter that affects integral dose, dose rate and patient clearance. For the calculations performed here it was assumed that dose equals terma.
what is monitor units in radiation therapy?
A monitor unit is a measurement of ionisation occurring in a treatment beam within the treatment head. One monitor unit is typically equal to a specific dose of radiation, at a specific depth in a water phantom, for a beam of a particular energy, with a particular field size and at a certain distance from the target.
Can you wear jewelry during radiation?
You do not need to remove your jewelry or watch unless you wear it on the area being treated. Marks will be made on your skin or on a mask to ensure that the radiation is aimed at the same area during each treatment.
What is Superflab made of?
Superflab is made of a proprietary synthetic gel, resulting in a molded material that does not suffer inelastic strain from normal stresses. Consequently, Superflab does not have to be bagged or wrapped in plastic film to maintain its shape during treatment. You may also read,
Why is a bolus used during radiation?
In radiation therapy bolus is often used when treating uneven areas of a patient, such as at the nose or ears, to make up for missing tissue, or to provide build-up of dose to the skin surface. The bolus should be tissue equivalent, sufficiently flexible to conform to the patient surface, durable and cost effective. Check the answer of
What is bolus effect?
In medicine, a bolus (from Latin bolus, ball) is the administration of a discrete amount of medication, drug, or other compound within a specific time, generally within 1 – 30 minutes, in order to raise its concentration in blood to an effective level.
What is isodose curve?
ISODOSE CURVES DEFINITION: Isodose curves are the lines joining the points of equal Percentage Depth Dose (PDD). The curves are usually drawn at regular intervals of absorbed dose and expressed as a percentage of the dose at a reference point. Read:
What is tissue maximum ratio?
Tissue Maximum Ratio (TMR) The TMR is a special case of the TPR, where the depth y used for the comparison is at the depth of maximum dose zmax (depth z).
