**8. Conclusion**

*6.2.1. Midbrain*

12 Cancer Survivorship

*6.2.2. Pons*

*6.2.3. Medulla*

**6.3. Pituitary gland**

can be as high as 50–100%.

laterally by the temporal bone.

**6.4. Temporal lobe**

**7. Discussion**

It starts from the nigral substance of the cerebral peduncle and ends upper border of pons.

*Dose recommendations*: Dmax—54 Gy. The entire brain stem can be treated to a dose of 54 Gy with little risk of serious side effects. [21]. Mean time of onset of symptom is 17 months (range 4.5–19 months). Smaller volumes (1-10 cc) may be irradiated to 59Gy at fractionations ≤2Gy [22].

A small gland, it is difficult to visualize in CT, but sella turcica can be used as a surrogate marked and the inner boundary of the same can be contoured for its delineation. The gland

CT density of pituitary gland is similar to brain. Upon contrast administration, the gland may

*Dose recommendations*: DMax 45Gy (for pan hypopituitarism, lower for Growth hormone (GH) deficiency). The anterior pituitary has 5 different types of cells, each with different radiosensitivity. Most sensitive is the GH axis followed by the gonadotropin, ACTH and TSH axis. GH deficiency has been noted in relatively lower doses, and has been reported for TBI for doses as low as 10 Gy [23], but the incidence increases substantially after 30 Gy where the incidence

Contouring of temporal lobe should include the hippocampus, parahippocampal gyrus and the uncus. The basal ganglia and insula are excluded from the contour. Cranially it starts for the superior end of sylvian fissure and ends inferiorly at the base of middle cranial fossa. Medial boundary is marked by cavernous sinus, sphenoid sinus and the sylvian fissure and

The modern radiotherapy in HNC have revolutionized treatment outcome especially in terms of acute and late toxicity. It thus brings about a clear change in treatment outcome. One important aspect in preserving the QOL is the OAR's. We, as radiation oncologist are much

lies immediately below the brain and is connected to the hypothalamus by its stalk.

become more hyperintense than brain due to the rich vascular supply.

Better visualized as an oval structure in sagittal sections, it is easily delineated.

Medulla starts from the lower end of pons to the lever of tip of dense of axis.

The chapter summarizes basic day to day information for a radiation oncologist to delineate OAR's in HNC radiotherapy. There are several updates and the readers are encouraged to go through them at a regular interval. We will be publishing a detail clinical end point based acute and late toxicities of these OAR's at a later date.
