Brain

Question 1

where do you usually SIM to?

Answer 1

top of skull to C3-C5

Question 2

what are common MRI scans that are fused with the CT?

Answer 2

T2/FLAIR

T1 + gadolinium

Question 3

toxicities from brain radiation

Answer 3

headache, tinnitus, fatigue, gait distubance, memory impairment, blurred vision, ataxia, constipation

Question 4

common brain fractionations

Answer 4

60/30, 40/15, 25/5

Question 5

PTV margin in brain

Answer 5

3 mm

Question 6

whole brain common fractionations

Answer 6

20/5 (palliative), 25/10 (prophylactic cranial irradiation), 30/10 (palliative with hippo scparing for patients living > 6 months. Current trials comparing whole brain + hippo sparing to SRS/SBRT for multiple mets)

Question 7

CTV margin in brain

Answer 7

1.5- 2 cm

Question 8

best way to describe what D2cc is

Answer 8

coldest dose of the hottest 2 cc

Question 9

constraints for 2 Gy fx (ie 60/30)

Answer 9

Brain-PTV < 23.5 Gy
brainstem dmax < 59 Gy
spinal cord dmax < 50 Gy
cochlea and inner ear dmax < 45 Gy
eye dmax < 45 Gy
hippocampal dmax < 16 Gy
hippocamapl dmean < 6 Gy
lens dmax < 4-5 Gy
optic nerves and chiasm dmax < 54 Gy

Question 10

Constraints for 20 Gy/5 fx

Answer 10

lens dmax < 10 Gy
eyes dmax < 22 Gy
optic nerves dmax < 22 Gy
brainstem dmax < 33 Gy

Question 11

constraint on hippos if using hippo sparing

Answer 11

D100%< 9 Gy

Dmax < 16 Gy

Question 12

inferior border for PCI vs WBR (non PCI)

Answer 12

non PCI: cranial base/foramen magnum

PCI: below c1 OR c2 VERTEBRAE, WANT TO INCLUDE ALL SPACES WHERE csf CIRCULATES