How is radiaton delivered?
So we already know that radiation therapy is good for treating specific areas in the body that have tumors that cannot be cut out by surgery, or places where surgery has likely left cancer cells behind.
Most of the normal cells circulating in our body have the ability to repair certain kinds of damage caused by radiation. However, cancer cells have lost that repair mechanism. Radiation treatments take advantage of this by causing irreparable damage to cancer cells, while sparing normal cells as much as possible.
In order to kill cancer cells, a certain amount of radiation dose needs to be given. However, if all of the dose is given in one sitting, the side effects can be very significant, depending on a number of factors. But when the radiation dose is broken into smaller pieces, the side effects are lessened, and the treatment is more manageable. That is why it can take multiple weeks to finish a course of radiation treatment.
We have been speaking about external beam radiation treatments. This is the most common form of radiation delivery. There are other ways to given radiation as well; the second most common form is through brachytherapy. We will talk more about brachytherapy in another section.
External beam radiation treatments are given on machines called linear accelerators. These machines are capable of producing photons and electrons which are used to treat cancer.
For most external beam radiation treatments, the patient lies down on a flat treatment table, and the linear accelerator has a treatment head, called a “gantry”, which rotates to specific locations. The treatments themselves are painless. Depending on the complexity of the treatment plan (discussed below), the treatments can last anywhere from 5 to 30 minutes or more, but most are somewhere between that range. Most of the time actually involves setting the patient up in the appropriate position.
Radiation treatments require careful planning. The goal of the radiation treatment is to target cancer cells, and to spare normal cells as much as possible.
Before starting radiation treatments, patients undergo what is called a “simulation” session. The purpose of the simulation is to set up the patient in the treatment position, and to collect data so that a treatment plan can be constructed.
Oftentimes, a computerized version of the patient’s body is made and imported into a treatment planning computer. This is often done with a CT scan, and is called 3D CT simulation planning. The radiation planning team– usually the radiation oncologist, dosimetrist, and physicist– then get to work designing a treatment plan that will best target the tumor, and spare the normal tissues as much as possible.
During your radiation treatment, your radiation oncologist will see you once a week to make sure you’re doing well, and that if any side effects arise, that they are managed. Of course, should you feel uncomfortable at any time during the treatment process, the radiation oncology team is availiable at any time to meet your needs. There also may be instances where you may not be in the oncology clinic, and require immediate medical attention; it is very important to act prompty during these situations and to seek immediate help via emergent means if necessary.