Dose Ratio and MU Calculation Lectures - Part III

[@sudhirdas8]

Just fantastic - thank you so much! So helpful.

[@SENADA-o4t]

Thank you for amazing videos! So easly understanding 🍀 Everything you posted is so useful! Please share more content. Greetings from Bosnia❤

[@mediphysman]

thank you Seneda! I am working on a full course of videos on Radiation Biology. hopefully they will as helpful as the previous videos.

[@SENADA-o4t]

@@mediphysman looking forward to it 😍

[@SasiKumar-xx6pd]

Nice presentation sir.

[@alvarofabio5721]

can u please make a vedio about big water phantom and the dose profile evaluation :) thx for the nice lectures

[@imandipaulinharmoniel6530]

Thank you sir for the great video. Now what happens if the beams arent equally weighted ???

[@mediphysman]

in this case, more MUs would be delivered by the higher weighted field and fewer by the lower weighted field.

[@ManuelRodriguez-ne9dn]

Thank so much for taking your time explaining each step , before this video I was so lost, I looked for medical physics tutors but no luck, Best of luck in your channel. Here is an idea to increase the channel content, what if you can make a video for each chapter on Medical Physics Book i.e Khan’s The Physics of Radiation Therapy

[@SENADA-o4t]

Same here! Or maybe Podgorsak? In fact, I would be thankful with only more videos on this topic 😂

[@mediphysman]

Manuel. this is a good idea. im going to look into possibly doing this.

[@rizwanulhaq7580]

More videos for MU calculations

[@sirpatrick6073]

Pls for the scatter factors, a 15 x 15 field gives 1.019 and 1.012 for Sc & Sp respectively. And for the 20x20 cm field size, we have 1.030 and 1.021 for Sc and Sp respectively. So how did you get 1.025 as Sp for your MU calculation

[@sirpatrick6073]

Also,how did you get a depth of 8cm for the calculation I just referenced

[@mediphysman]

thank you for the question sirpatrick6073. for the Sc and Sp factors, we calculated an equivalent square field size (@4:55) of 19 x 19 cm2. so we interpolated between the Sc and Sp values for 15 x 15 cm2 filed and 20 x 20 cm2 field listed in the Sc/Sp table (@6:04) to get Sc = 1.025 and Sp = 1.019. Also, the 8 cm depth is a result of wanting to calculate dose a the midline of the brain, where the thickness (distance of separation) for the head was 16 cm. there for midline is at 8 cm depth. Hope that helps. .....thanks for watching!

[@MrSandrita1986]

I want to resolve many exercises about this topic, can you share me a book or pdf?

[@brunopinheiro1591]

Hey! how can I to know at wich depth/distance I need to calc the equivalent square field of 20x18? At surface or at isocenter?

[@brunopinheiro1591]

thanks very much for this video! rsrsr i wanna to work as physical of radiation therapy in the next year

[@mediphysman]

Bruno, that's a great question. First, remember our field size is defined at treatment isocenter. this is the most important point. Since we are using an isocentric setup (SAD = 100 cm), we know our treatment isocenter is located 8 cm deep in the patient. Therefore, our equivalent field size for the 20cm x 18cm field is defined at 8 cm depth in the patient (i.e. isocenter). -- hope that helps, MediPhysMan.

[@DecodingUniverse]

nice

[@scienceoflife4061]

there is same mistakes in those interpolations