I have just been diagnosed with a T1N1M0 (HPV+) on my right tonsil tissue (I had my tonsils taken out as a kid). I had a MND on the right side of my neck in which they took out 18 lymph nodes, with one being postive. I am scheduled to undergo 33 sessions of IMRT in approximately two weeks. The dosage that they are scheduling me for are the following:

right tonsil area - 70 Gray
Left lymph nodes - 54 Gray
Right Lymph nodes - 60 Gray

Due to the size of the source and only one positive lymph, the local team is saying that I don't need chemo

A couple of questions:

1) Based on the limited information aboveiIs going with IGRT better than going with IMRT (Rapid Arc)? According to the Johns Hopkins web site they state the following "IGRT represents a further evolution of IMRT, meaning that the treatment session is delivered only after checking, on a daily basis and with the patient on the treatment table, the correct position of the target with respect to the machine. At Johns Hopkins this is done by acquiring a CT scan on the treatment table. A more precise treatment delivery implies fewer dose to the normal structures and a higher likelihood of treatment success"

My local facility has the IMRT (Rapid Arc) system so I would have to travel in order to go with a facility with an IGRT based solution.

2) Do the dosages above seem average, high or low based on the limited information above?

Laz,

Have you checked with your radiation oncologist (RO). I was treated with what they called IMRT but was actually IGRT. Some of the technical people just have not started calling the newer machines by this new term.

Your RO should be able to tell you exactly what you are getting. I would go with the IGRT. It is a more accurate method of treating Head and Neck cancers. By how much I don�t know.

Thanks for the information. When I was at the hospital today doing my swallowing test, I spoke with a tech who informed me that they do have both IMRT and IGRT systems. I am pretty sure that my Radiologist is proposing IMRT, however I will confirm with him tomorrow at the second part of my simulation. If that is correct, how would you propose that I tell him (and why) that I want him to use IGRT instead of IMRT?

Thanks for all you help/advice.

Laz,

Keep in mind that I am not a doctor and you should check with a real pro before making any decisions.
It was my understanding that in IMRT they make an assumption regarding how the tumor will react to the radiation and periodically take CT�s throughout the radiation schedule to check and make sure the radiation is getting the desired effect on the tumor.
In IGRT the machine takes a CT at the start of every session. The RO checks that each time you come in and can make any minor adjustments on the spot before you get the radiation dose for that day. IGRT sessions take a few minutes more each day because they stop for ten minutes or so to get the OK from the RO on staff that session (the RO may make an adjustment on the spot).

Anyone out there who knows better on this please pipe in.

Laz - sent you a PM about this.

If given a choice, I suggest you select the best technology available and I believe that would be IGRT with the guidance being CT based.

The very newest RapidArc systems (Novalis and Varian) are IGRT systems and can (optionally) provide real-time CT guidance. Most high-end newer systems also have some form of ART (adaptive RT re-planning).

RapidArc is also an available software upgrade for some older systems with do not necessary have the same guidance capabilities

As I recall, your planned grays seem about appropriate. You can search the NCCN Guidelines to confirm this.