linac

Question 1

lateral motion of the couch-if the couch moves to the right. If starting at zero, what happens to the lat value?

If the couch moves to the left.

Answer 1

moves toward lower numbers…999 and down

moves toward larger numbers…1 and up

Question 2

Describe longitudinal motion of the couch…

Answer 2

value goes up as the couch moves in. Fully retracted it is about 15.
fully extended is about 161.

Question 3

Couch rotation.
From the edge of the couch facing the gantry, if couch rotates right, what is true of the couch rotation?
To the left?

Answer 3

goes from 0 to 270 (opposite of gantry, which would be from 0 to 90 if it rotated right).

if it rotates left, goes from 0 to 90 (gantry would rotate from 0 to 270).

Question 4

Collimator
rotates to right (toward control room while at end of couch)

rotates to left

Answer 4

collimator goes from 0 to 90

collimator goes from 0 to 270

Question 5

Dmax

Answer 5

Superficial/Ortho...   0
Co-60...                     0.5 cm
6e...                            1.3 cm
9e...                             2.0 cm
12e...                           2.6 cm
16e...                           2.6 cm
20e...                           2.0 cm
6x...                             1.5 cm
10x...                           2.5 cm
18x...                           3.2 cm
25x...                           5.0 cm

Question 6

PDIs are a little off…

Answer 6

The data in the spreadsheet was taken with a farmer chamber (offset by 0.18), while we were scanning with a cc15, which has an offset of 0.15. So, there can be a difference of 0.03.
The chamber can be given an offset in the welhofer software that matches a farmer.