Title: Head: Organs at Risk & Tolerance Doses

First find the organs at risk. Always tap in the middle of the organ!

Brain

Q: Brain:

Left eye

Q: Left eye:

Right eye

Q: Right eye:

Left lense

Q: Left lense:

Right lense

Q: Right lense:

Left optic nerve

Q: Left optic nerve:

Right optic nerve

Q: Right optic nerve:

Optic Chiasm

Q: Optic chiasm:

Left CT marker

Q: Now you´ve found every organ at risk, find the left CT marker! The CT marker is very important to mark in the external contour.

Right CT marker

Q: Find the right CT marker.

Now you can see, how a ready contoured CT should look like:

[Image: ready contoured head CT]

[Image: Glandula parotis & submandibularis]

Here you can see the the organs at risk in MRI. First without contour, then ready contoured. For delineating the organs at risk in radiotherapy you will get a CT but it is good to know, how everything looks like in MRI.

[Image: head MRI]

[Image: MRI head contoured]

In the next step you should look at the tolerance doses of the organs at risk. You find them in the following link.

Tolerance Doses

- 45 Gy
- Dmax < 3 Gy
- Dmax < 54 Gy
- Dmax < 54 Gy
- Dmax < 54 Gy
- Dmax < 3 Gy
Q: Right lense
A: Dmax < 3 Gy; Dmax < 3 Gy
Q: left optic nerve
A: Dmax < 54 Gy; Dmax < 54 Gy; Dmax < 54 Gy
Q: optic chiasm
A: Dmax < 54 Gy; Dmax < 54 Gy; Dmax < 54 Gy
Q: brain
A: 45 Gy
Q: left lense
A: Dmax < 3 Gy; Dmax < 3 Gy
Q: right optic nerve
A: Dmax < 54 Gy; Dmax < 54 Gy; Dmax < 54 Gy