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
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!
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
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.
Just fantastic - thank you so much! So helpful.
Nice presentation sir.
Thank you for amazing videos! So easly understanding 🍀 Everything you posted is so useful! Please share more content. Greetings from Bosnia❤
thank you Seneda! I am working on a full course of videos on Radiation Biology. hopefully they will as helpful as the previous videos.
@@mediphysman looking forward to it 😍
Thank you sir for the great video. Now what happens if the beams arent equally weighted ???
in this case, more MUs would be delivered by the higher weighted field and fewer by the lower weighted field.
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
Also,how did you get a depth of 8cm for the calculation I just referenced
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!
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
Same here! Or maybe Podgorsak? In fact, I would be thankful with only more videos on this topic 😂
Manuel. this is a good idea. im going to look into possibly doing this.
can u please make a vedio about big water phantom and the dose profile evaluation :) thx for the nice lectures
More videos for MU calculations
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?
thanks very much for this video! rsrsr i wanna to work as physical of radiation therapy in the next year
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.
I want to resolve many exercises about this topic, can you share me a book or pdf?
nice
there is same mistakes in those interpolations