Hi,
I've just returned from Boston where I met with a radiation oncologist from Mass General. She reviewed my case (T1 tumor excision with one dirty margin) and recommended 61/2 weeks of 3D conformal radiation.
I did a search of the Foundation's forums and did not get a match. Has anyone every had this particular type of radiation or know about it?
I did a google search and found the following at: http://www.kcc.tju.edu/RadOnc/brachy/three.htm

"Utilizing computer-assisted tomography (CAT) scans performed in our department we are able to integrate this information and develop three-dimensional reconstructions of a patients anatomy. This allows us to better visualize the cancer and surrounding normal tissue in three-dimensions which was not feasible before the development of this technology. With this comprehensive ability to identify in three-dimensions the "target" and surrounding normal tissues, we can customize the radiation beams for each patient and more precisely aim the radiation beams while avoiding the surrounding normal tissues as much as possible.

A series of daily treatments are administered with a machine called a linear accelerator filled with a multi-leaf collimator. Treatments are given in brief daily sessions for a period of seven to eight weeks. This device delivers multiple converging beams of high-energy radiation to the prostate and surrounding tissues. The radiation energy causes the death of the cancer cells."

This sounds somewhat a lot like IMRT radiation but I don't understand the difference or the relative advantages of one type versus the other. Any advice would be appreciated. Thanks, Sheldon

Hi Sheldon,

I am not the expert here but it sounds just like IMRT to me.

Perhaps Gary has more wisdom here.

They are not the same. Some manufacturers, such as Siemens, confuse the issue more by using some of the terms interchangeably. 3D-CRT (conformal radiotherapy) is an older, less advanced technology than IMRT. The following article below discusses the fine differences between the two:

"Intensity-modulated radiation therapy (IMRT). Under computer guidance, "dynamic" multileaf collimators can change their shape during treatment, thereby giving rise to intensity-modulated radiation therapy (IMRT). IMRT can deliver radiation more conformally than 3D-CRT can, which allows for the delivery of higher doses. IMRT differs from 3D-CRT in that each x-ray beam is broken up into many "beamlets," and the intensity of each beamlet can be adjusted individually. As a result, IMRT has a significant advantage over 3D-CRT in inverse planning, which is the process by which a physicist, using a computer program, starts with the dose distribution desired by the radiation oncologist and works backward to determine the intensity of every beamlet necessary to achieve that distribution. By contrast, treatment planning with 3D-CRT is an exercise in trial and error."+


+Source - Recent advances in radiotherapy for head and neck cancers.
Ear, Nose & Throat Journal, Oct, 2001, by Rachel H. Chou, Richard B. Wilder, Michael S. Wong, Kenneth M. Forster

See I told you he would!

Sheldon, In your post the second to last sentence says "This device delivers multiple converging beams of high-energy radiation to the prostate and surrounding tissues."

I hope they don't think that head and neck is "surrounding tissue" otherwise you need a third opinion!

I hope you have my sense of humor if not, my humble apologies,

Actually IMRT, PBT and 3D-CRT were initially designed for prostate cancer treatment because of the need for tissue sparing techniques and precision accuracy. This transferred well to the head & neck.

Mark,
Reading your post was one of the few times I've been able to laugh recently. Thanks.

Sheldon,

Glad to be of service!

Just to follow up Gary's very informative post. I had to return to Boston for my simulation, mask, etc. I asked the radiation oncologist about the difference between IMRT and 3D-CRT.
Her response was that the basic difference is that IMRT enables one to modulate each specific beam to get maximum conformity while 3D does not. She was of the opinion that since they are not targeting a tumor but rather trying to clean a positive margin and any additional loose cancer cells, that they want to deliver a uniform beam but proscribe carefully the radiated area. She said I would get the same benfits as IMRT (essentially save the parotid gland and tissues on the left side of my mouth, throat and neck while they radiate the right side.) but that there was no real advantage to IMRT in my case.
Since Mass General has a variety of radiation technologies at their disposal including IMRT, I am assuming that this is the right treatment for me.

It sounds like a far better approach than XRT.