I don’t know the answer, but I would asking what benefit is to be gained by doing an additional 6Gy onto the area already just treated with 30Gy? ...and would this preclude further 15Gy treatment sometime in the future if that ever became a consideration?
Just an update that my expanded field got 21gy total for 7 days of 3gy and my first radiation area got 30gy total with both 5 day treatments. The RO did use a block over my upper palm (my mcp joints on palm side) as to only have a small overlap area get the 36gy total. So hopefully this works to stop progression!
Same as before, just reworded: I don’t know the answer, but I would be asking what benefit is to be gained by doing 36Gy instead of 30Gy? ...and would this preclude further 15Gy treatment sometime in the future if that ever became a consideration?
It is generally not very useful to work in radiotherapy with different abutting radiotherapy fields; only in certain situations a "shrinking-field-technique" or a "field-in-field technique" is used, e.g. to cover a high risk area in the central part of the RT-fields. In general, abutting fields create inhomogeneous irregular dose distributions, which may have undesired consequences (see attached figure - Example for a chestwall radiotherapy plan with three abutting RT-fields A, B an C)
There are two possible problems involved with this type of "Patchwork Radiotherapy"
(1) If the RT fields overlap, an undesired OVER-DOSAGE (= HOT SPOT) may result which can induce side-effects in the overlapping zone which are usually not observed in the other regions of the RT-fields.
(2) If the RT fields do not abut with each other a more or less broad gap may result with an undesired zone of UNDER-DOSAGE (= COLD SPOT) and a possible lesser effect on the target tissue than intended.
Moreover, one has to kep in mind, that on any RT field edge of a radiotherapy portal an under-dosage region has to be accepted anyway due to lesser secondary electron interactions in the peripheral than in the central zone of the RT field. Therefore, the marked skin line of the RT-field edges often do not reflect the lines at which a full 100% RT-dose is already reached. This may be at 5 - 10 mm "inwards" depending on the type and energy of radiation (electrons, orthovolt-X-rays).
The attached figure explains this situation for three abutting RT-fields with the typical "cold spots" (Blue zone --> < 80% RT dose) on the field edges and the possible "hot spots" (Red --> > 120% RT-dose on the overlapping RT fields).
The unclear "actual situation" of inquisitivelady reflects a probably lesser experienced physician with regard to the initial examination and palpation (or palpatory skills of the physician) for the initial preparation and planning of the RT-field of the DD hand palms.
This lack cannot be compensated by a later "patchwork RT dose pattern" for different regions of the affected hand palm. Photographic documentation should be a requirement for any chosen field set-up.
My advice would be to stick with the 30 Gy (including two RT-series of each 15 Gy) protocol and await if a relapse / progression may possibly occur in the future at the lesser irradiated area which might then be treated with a 3rd RT-series.
Overall this approach is not the "State of the Art Radiotherapy" !
Given the very edge of the field gets less radiation, I feel I do not want to use the block as this border is where progression is up pinky and ring finger. At this point I am only given two choices to use block or not use block on two extra days. RO does not want to do a third 15gy on entire area as I asked this already, I will ask again if will consider only if progression. If I am not given an option for a third radiation if progression happens, I will have to do the 21gy 7 day protocol which in my mind was in the study by you, Prof. S. But of course without the additional 15gy on original radiation area. So in effect i will be a patchwork of 21gy and 36gy but my only wish is that luck is on my side with this. If I only have the 7 day as an option for my second treatment, I hope you would agree that treating the whole area with 21gy this treatment is better than using a block with this 21gy treatment. I know this does not allow me another 15gy session in the future which of course is sad, as it would be nice to have that in the future if progression.
I hope this is a warning to others to always go to an experienced RO even if you have to travel so you dont end up like me and my one of a kind radiation area of patchwork radiation, I initially went to only one in my area which was a mistake. This forum has been such a valuable resource, and I am so thankful for Prof. Seegenschmiedt’s knowledge and for bringing the choice of radiation for Dupuytren’s and LD to the world. We can never thank you enough Prof. S!!!!
Prof.Seegenschmiedt:My advice would be to stick with the 30 Gy (including two RT-series of each 15 Gy) protocol and await if a relapse / progression may possibly occur in the future at the lesser irradiated area which might then be treated with a 3rd RT-series.
Of course your local RO should be advising you along with your own decision, but I feel you are going where no-one else has been.