QUANTEC

Question 1

Kidneys

Answer 1

For bilateral kidneys, the volume receiving 28Gy should be less than 20% for a less than 5% chance of clinical dysfunction, months to years post treatment.

Question 2

Penile Bulb

Answer 2

V50<90 to create a less than 35% chance of severe erectile dysfunction months to years post treatment

Question 3

Oesophagus

Answer 3

Mean dose of 34Gy creates a 5-20% chance of RTOG grade 3+ oesophagitis (severe fibrosis, able to swallow only liquids, may have pain swallowing)

Question 4

Lungs

Answer 4

For combined lungs, V20<30 gives a less than 20% of symptomatic pneumonitis

Question 5

Peritoneal Cavity (stomach)

Answer 5

45Gy to the whole organ for a less than 7% chance of ulceration, perforation, and mucosal erosion, months to years post treatment

Question 6

Small Bowel

Answer 6

The volume receiving 45Gy should be less than 195cc for a less than 10% chance of RTOG grade 3 toxicity
(Obstruction or bleeding requiring surgery).

Question 6

Bladder

Answer 6

Maximum radiation dose of less than 65Gy to the whole organ creates a less than 6% chance of the Grade 3 RTOG endpoint (severe frequency & dysuria, severe telangiectasia, frequent haematuria, reduction in bladder capacity).

Question 7

Rectum

Answer 7

V50<50%
V60<35%
V65<25%
For less than 10% chance of an RTOG grade 2/3 late rectal toxicity months to years post treatment (g2 is moderate diarrhoea and colic bowel movements, excessive rectal mucus or intermittent bleeding. G3 is obstruction or bleeding requiring surgery)

Question 8

Heart

Answer 8

When considering the whole heart, the volume receiving 25% should be less than 10% which creates a less than 1% chance of long term cardiac mortality.

Question 9

Spinal Cord

Answer 9

Maximum radiation dose of 50Gy (partial organ) creates a less than 0.2% chance of the endpoint reaction with 3DCRT (radiation induced myelitis necrosis leading to paralysis and incontinence)

Question 10

Larynx

Answer 10

A dose of less than 66Gy within the organ for a less than 20% chance of vocal dysfunction months to year post treatment.

Question 11

Parotid

Answer 11

A mean dose of less than 25Gy for the combined parotids creates a less than 20% chance of long term salivary function of less than 25%.
A mean dose of less than or equal to 20Gy for a single parotid creates a less than 20% chance of long term salivary function in the effected gland of less than 25%.

Question 12

Brain

Answer 12

Maximum radiation dose of less than 60Gy within the whole organ for a less than 3% chance of symptomatic necrosis months to yrs post treatment

Question 13

Brain stem

Answer 13

Maximum radiation dose of 54Gy within the organ creates a less than 5% chance of the endpoint reaction months to years post treatment. The endpoint is neuropathy and necrosis

Question 14

Optic nerve

Answer 14

Maximum radiation dose of less than 55Gy within the whole organ can create a less than 3% chance of the endpoint reaction months to years post treatment. The endpoint is optic neuropathy leading to blindness in the associated eye.

Question 15

Optic Chiasm

Answer 15

Maximum radiation dose of less than 55Gy within the whole organ can create a less than 3% chance of the endpoint reaction months to years post treatment. The endpoint is optic neuropathy leading to blindness in both eyes.