No xrt bro. ALARA!
Weekly port films could easily be "attacked" from ALARA standpoint too. Their ubiquity much more due to tradition than EBM, esp in case of breast where we could just have the MD come to room and confirm a daily clinical setup and take a standard photograph (vs an MV film) to confirm. No data to support daily IGRT for left-sided, conversely no data to support not doing daily IGRT on right-sided. In other words, ALARA a good argument to prevent daily IGRT for left-sided too.
"I see many cases..." Anecdotal! Not really EBM. My anecdotes are pretty good too! I see many right sided cases where a 5mm shift would shoot the lung V20 up a few percent and we have evidence V20 matters. Also I see many right sided cases where a 5mm shift would shoot the the PTV mean dose down and we have evidence that PTV dose matters... (I could go on, as you know!)
The increased integral dose from daily CBCT over ~15fx is very minimal compared to the integral dose from the EBRT itself. You know this. It's kind of like having a private jet, being simultaneously concerned about climate change, and then saying "The CO2 from my private jet is warming the earth too much; thus I will only use it sparingly."
This is really key to the discussion of course. There's ~1% out of field scatter in general from the EBRT, but that's based on MUs and not strictly dose. In other words, giving 42.5Gy needs about ~84Gy of MUs and we will see ~0.8Gy mean dose in that other lung from EBRT alone, worst case I imagine. If you do IMRT(!!!) as they did in IMPORT-LOW it could be a higher MU/Gy ratio. But be that as it may the daily CBCT dose is about 2 cGy, times 15 = ~0.3 Gy lung dose from CBCT.
Well back to my climate analogy... maybe there are pluses and minuses with some increased CO2. And maybe there are pluses and minuses with the wee bit extra dose CBCT provides: no joke... may be treating some aches and pains etc. The thing about as low as reasonably achievable (ALARA)... "reasonable" is very subjective!
Do tell...
A lead block.
Our physicists added a layer of soft material on the outer sides, it is supposed to absorb electrons that are produced by the block when you hit it with photons (in theory). There was some concern of excessive reaction on the skin of the irradiated leg that was "touching" the block.
clever
I don't think so. This publication suggests that there is no difference in brachial plexopathy incorporating newer techniques. Even the dosimetry seems essentially equivalent.. That they would make an inference based on 4 vs 1 events here (when reviewing almost 500 patients) is not very smart.
Is this method of estimating dose even appropriate? Isn't the most important measure integrated dose (or even more significant, dose to structures outside of the target)?
In retrospect "You will service us" was an unfortunate turn of phrase. The Borg... out there #MeToo'ing the whole galaxy.
Ours do and I hate checking them during cross coverage. I miss a good old port film. Is the boob in the field? Yes, then treat. With CBCTs if the skin is on but the bones are off do I care? My feelings on breast are well known. Here is yet another way to make something easy a little bit harder ☹️
Can you link to that mednet discussion. Searching for stuff there is unwieldy.
