Refers to the energy deposited at a specific point in a medium. The dose is measured at a specific point (in a patient or phantom) and is commonly measured in Gray (Gy). (W/L, pg. 493).
A 45 degree wedge is inserted into a field to modify the isodose curve. The toe section will allow (greater or lesser) intensity in part of the beam.
Greater.
Depth
The distance beneath the skin surface where the prescribed dose is to be delivered (W/L, pg. 494)
What is the Dmax for a 18 MV beam?
3.5 cm (RT Essentials, pg. 140).
The area enclosed by the isodose surface selected.
Treated volume.
When looking up the PDD or TMR for a given depth and field size, _______ should be used when there are blocks or MLC.
Effective Square (W/L, pg. 504).
Radiation Therapy prescription
Communication tool between the radiation oncologist and the treatment planning and delivery team (medical dosimetrist and radiation therapist) and provides the information required to administer the appropriate radiation treatment (W/L, pg. 493).
Calculate the Gap:
Field 1- Length = 17 cm, Width = 6 cm, Depth = 3 cm, SSD = 92 cm;
Field 2- Length = 15 cm, Width = 12.5 cm, Depth = 3 cm, SSD = 91 cm.
(17/2 x 3/92) + (15/2 x 3/91)
(8.5 x .0326) + (7.5 x .0324)
(.2771 + .0243)
Gap= .52
ISCF (for SAD Set-ups)
(Reference distance / Source Calculation Point Dose [SCPD])^2
*Reference distance = 100; SCPD = The set up SSD + Depth (W/L, pg. 508).
The anatomical point A used when calculating dose for cervical and uterine treatments is located:
2 cm superior and 2 cm lateral to the center of the cervical os.