A Comprehensive Guide to Intensity-modulated radiotherapy (IMRT) Treatment

Intensity-modulated radiation therapy (IMRT) stands as an advanced form of radiation therapy in cancer treatment. By utilizing potent energy beams—derived from X-rays, protons, or alternative sources—IMRT precisely targets cancer cells, sparing healthy tissue.

IMRT employs customized radiation beams, meticulously tailored to match the contours of the cancerous area. These beams possess the flexibility to move along arcs during treatment delivery, allowing for optimal coverage. Additionally, the intensity of each beam can be finely adjusted, ensuring accurate radiation dosage.

This technique enables the safe and efficient delivery of radiation therapy, minimizing damage to surrounding healthy tissues. IMRT's versatility extends to the treatment of both cancerous and benign tumors across various body regions, with the primary objective being to administer the appropriate radiation dose to the target while mitigating collateral damage.

The following types of cancer can be treated by IMRT:

Breast cancer
Cervical cancer
Colon cancer
Lung cancer
Prostate cancer
Stomach cancer
Uterine cancer
Other cancer types

Types:

Step-and-Shoot IMRT:( the treatment is delivered in a series of small, discrete steps.)
Sliding Window IMRT:(known as dynamic MLC,) This involves continuously moving the MLC leaves while the radiation beam is on, allowing for a more seamless delivery of radiation dose.
Volumetric Modulated Arc Therapy (VMAT):(This is an advanced form of IMRT where the linac delivers radiation continuously as it rotates around the patient.)
Tomotherapy:(This technique combines IMRT with computed tomography (CT) scanning.)It delivers radiation in a helical manner.

Following are the signs and symptoms associated with IMRT:

General Side Effects Fatigue, Skin Changes, Hair loss
Dry Mouth (Xerostomia), Difficulty Swallowing (Dysphagia)
Cough, Shortness of Breath, Abdomen and Pelvis
Cognitive changes such as difficulty

Before starting treatment, the patient will attend a planning session called simulation, or “sim.” The goal of the simulation is to gather all the necessary information for the radiation oncology team to design an effective treatment plan.

During the simulation:

The patient will undergo a CT scan to visualize the tumor. Additional imaging, such as an MRI or PET scan, may also be performed.

The patient will receive small tattoo dots on their body to help align their position with the LINAC (linear accelerator) during treatment. These markings are about the size of a freckle. In some cases, the markings may be drawn on, but they must remain throughout the entire treatment period.

The radiation oncology team will determine the optimal positioning for the patient during simulation, ensuring the machine can deliver energy beams at precise angles to target the tumor. This may involve fitting the patient with special accessories to maintain the correct position, such as a custom mold to keep the body in place.

Using the information gathered during the simulation, the radiation oncology team will design energy beams of varying intensity to accurately target the tumor.

The duration of recovery varies based on several factors such as radiation dosage, treatment frequency, and the specific body part receiving radiation. While some individuals may experience relief from side effects within a few weeks, others may require a month or two to feel better.