8.3 - Megavoltage photon beam profiles

[@maryjones7014]

I think the umbra is the area outside of the field edge (dose

[@roscribbles4155]

Hiya, are you sure you're not thinking of the penumbra?

[@7891memo]

Mary Jones umbra, as the name indicates, is the area where the dose level is uniformly distrubuted with tbe slightest dose variation.. The penumbra is the semi-shadow area, where the beam rapidly falls off

[@TheBeGoode]

Indeed according to the IAEA textbook (www-pub.iaea.org/MTCD/publications/PDF/Pub1196_web.pdf p 196) it is the region "outside the radiation field, far removed from the field edges [...] results from radiation transmitted through the collimator and head shielding". "umbra" also means shadow so it makes more sense...

[@chetanverma5532]

Amazing lecture sir, please share more such videos on other concepts. :)

[@vanessadiab3999]

great video! could you do a small video explaining image-guided radiation therapy (IGRT)?

[@mxriamm._8021]

Doesnt increasing the SSD cause the beam to be attenuated more by the air particles so it hardens the beam and makes it more penetrating???

[@mqekelakhesa8351]

is it troubling asking you to put words as you are speaking sir? your accent is not audible somewhere.

[@chineloonwualu7429]

You are so fast..I can't even keep up with the explanations..can you go slower