plan evaluation

Question 1

quantitaive analysis:
DVH

Answer 1

look at DVH
check target coverage + MAX to see if homogenity of dose is in accordance to ICRU50

Question 2

how to check target coverage

-max dose

Answer 2

-PTV LINE= 95% on x axis (REV dose) to the 99% on y axis (Ratio %)

-top corner

Question 3

check OAR

Answer 3

click absolute dose and check DVC

Question 4

CONTOUR;

Answer 4

review delineated TV and OAR

make sure all OAR contours are there

Question 5

beam arrangements and fields

Answer 5

-ensure fields are entering at angle thru body that arent going thru too much normal tissue

-beam eye view to check MLC

Question 6

OAR

Answer 6

-see priority of contrainst (end point)
- look at corresodning isolines on plan

Question 7

prescription

Answer 7

total dose
dose per fraction
image guidance

small PTV margins=need more frequent and accurate imaging

Question 8

when talking ab coverage

Answer 8

ICRU50 accepts that there will be some homogenity in target coverage. It allows a variation of -5 and +7%.

if plan is prescribe 100% of dose min should be 95 ansd max should be 107

Question 9

check if dose max is inside or outside

Answer 9

if inside the PTV , it is preffered to treat PTV with more dose than normal structures