Radiation Therapy: Surgical Methods that Don't Break the Skin

By : Art Gib

Cancer is nearly the leading cause of death in the U.S., and more and more people need help in treatment. Luckily in recent years there has been a good deal of technological headway that has come about. From identifying and treating the tumors in the body, new radiation technology and techniques have already come into use with a lot of promise.

New technologies include IMRT, IGRT, radio surgery, and TomoTherapy.

The field of radiation therapy employs several means to irradiate tumors and cancer masses within a patient. For the most part, beams of x-rays or other atomic or sub-atomic particles are the most common used means to disable the cancer cells within the body, which enter the body in wave-form so it's non-invasive.

This field of application is also known as external beam radiotherapy. There are several other techniques in radiation therapy, such as sealed source radiotherapy and unsealed source radiotherapy where application can be done through injection or ingestion.

External Beam Radiotherapy

The external beam technology uses charged particles, mostly x-rays, and sends these wave forms through the skin to the affected area. Linear accelerator machines are used in these therapy types to emit the beams. The major advancements have been more in the planning stage of the therapy.

The patient's tumor mass is the trickiest part. Computers and software have come along to help map out and plan the route where the beams are directed. 3-D mapping software and hardware, such as the multileaf collimator which alters the beam's shape with varying metal leaves near the laser eye, have made this process easier.

Intensity-Modulated Radiation Therapy, or IMRT, was a recent advancement in external beam technology. This incorporates the use of the linear accelerator beam and the 3-D mapping software. The IMRT uses software to map and find the tumor, as well as generate different doses of radiation to the tumor to reduce the harmful affect of radiation on good tissue that surrounds the cancer.

The IMRT process uses CT scans for much of the mapping and planning, however CT scans need to be constantly made for each session, making the process quite lengthy for the patient and therapy workers.
Image Guiding Beam Technology

The next step in external beam radiotherapy is the release of the Image Guided Radiation Therapy, or IGRT. This new process has only been actively used within the past several years by clinicians.

The IGRT technology will use real time CT or x-ray imaging while using a linear accelerator's beam to do the work. This not only saves much time for patient, but also becomes more accurate. While the IMRT technology would have to compensate for any shifting of the mass within the body by firing a wider area beam typically to mass, the IGRT methods can calculate any shifting so when the beam is emitted less healthy tissue is affected. This helps bring down side-effect problems in the long run, such as deadly secondary cancers from radiation.

Targeting Brain Cancer

Radio therapy has proven effective to many deadly brain cancer masses. This again is a non-invasive means to treat abnormalities and tumors. Radio surgery is often the term used for many radiation treatments for the brain. The linear accelerator is used to treat the brain in radio surgery, as well as photo beam accelerators and the new proton beam accelerator technology.

One form of hardware and suite software that is used to treat brain cancer that uses the x-ray linear accelerator is TomoTherapy. This is quite new as well. This incorporates IMRT beam use; however it also will operate in a full circular "helical" manner around the patient.

The beam can be applied in a full 360 degree manner. The ring "gantry" holds both the beam eyelets as well as the CT scanning imagery, so the 3-D mapping of the skull in brain surgery can be done. The helical application that TomoTherapy can deliver makes it powerfully accurate in all many different cancer treatments, especially those of the brain.