Conformal Radiotherapy - Types and Advantages

What Is Conformal Radiotherapy?

Conformal radiation is a treatment in which a high-dose volume is formed to conform to the target volume while reducing the dose to important normal tissues in the surrounding area. Because conformal radiation aims to adapt the dose to the target, precise target delineation is essential.

What Are the Different Types of Conformal Radiotherapy Techniques?

Conformal treatment is a basic method for limiting dosage to all normal tissues while fitting the dose distribution to the target volume. As a result, the primary goal of a radiotherapist is to provide the finest structural radiation therapy possible. The three principal types of conformal radiation techniques are three-dimensional conformal radiotherapy (3DCRT), intensity-modulated radiation treatment (IMRT), and volumetric modulated arc therapy (VMAT).

Conformal Radiotherapy in Three Dimensions (3DCRT) -

The first conformal therapy approach produced was three-dimensional conformal radiation, which used three-dimensional treatment planning with contoured fixed fields. Conformal radiotherapy plans are accomplished by hitting the target with beams of varying weights, sizes, forms, and orientations.

Radiation Treatment With Intensity Modulation (IMRT) -

Researchers developed the IMRT technique by combining inverse planning with intensity-modulated beams. It has become a key therapy approach for curative treatment and routine practice for numerous malignancies during the last 15 years. When compared to conventional radiotherapy, which uses the same fraction size for all target volumes with successive reductions in field sizes to avoid normal critical structures, intensity-modulated radiation therapy (IMRT) is one of the most conformal and effective techniques because all target volumes, including gross disease and subclinical extensions, are treated simultaneously using different doses. Because intensity-modulated radiation therapy (IMRT) optimizes dose distributions, less normal tissue receives high radiation doses.

Volumetric Modulated Arc Therapy (VMAT) -

Volumetric modulated arc therapy (VMAT), a mix of intensity-modulated radiation therapy (IMRT) delivery and optimization approaches with arc therapy, has recently become a key method for the delivery of conformal therapy. This technology delivers rotating intensity-modulated radiation therapy (IMRT) utilizing a standard C-arm linear accelerator configuration with synchronized rotations and arc movements. As a result, the gantry constantly spins throughout a volumetric modulated arc therapy (VMAT) treatment. One significant benefit of current VMAT systems is that they can be delivered significantly quicker than fixed field intensity-modulated radiation therapy (IMRT).

What Are the Advantages of Conformal Radiotherapy?

• 3D conformal radiation generally increases the necessity for correct anatomic delineation.

• This necessitates an accurate description of the tumor's location and a full understanding of potential infiltration and dissemination mechanisms.

• In terms of dosage homogeneity, an intensity-modulated radiation therapy (IMRT) plan should always yield a more homogenous dose distribution than a plan created using uniform beams. It also has the potential for adaptive therapy, which is the treatment plan adjustment based on tumor shrinkage and organ movement imaging.

How Is Conformal Radiotherapy Planned?

Three-dimensional (3D) conformal radiation treatment is associated with various imaging modalities, including computed tomography (CT) scans. Using computed tomography (CT) scans simulator for beam placement has replaced the traditional simulator fluoroscopic planning machine for plan creation. Digitally reconstructed radiographs connect the plan to the treatment unit in a way that is quickly displacing the conventional simulator.

Three-dimensional (3D) conformal therapy includes shaping the beam to fit the target as seen on computed tomography (CT) scans. The doctor arranges the rays to optimize exposure to the tumor while minimizing radiation to normal tissues. Patient, tumor, and natural target movement necessitate immobilization of the patient and an appropriate margin around the targets to avoid a marginal miss.

Which Cancers Can Be Treated by Conformal Radiotherapy?

3-D conformal radiation therapy benefits the following cancers:

• Esophageal cancer.

• Pancreatic cancer.

• Brain tumor.

• Lung cancer.

• Breast cancer.

• Liver cancer.

• Bladder cancer.

• Rectal cancer.

• Lymphoma.

• Stomach cancer.

What Is Gamma Knife Therapy?

The non-invasive gamma knife is an excellent alternative to conventional brain surgery. The gamma knife, often conducted in a single outpatient treatment session, helps patients avoid incisions, scars, and lengthy hospital stays. Gamma knife therapy is the most precise stereotactic radiosurgery for various illnesses. As the gamma knife does not have a blade, thus no incision is used only to treat malignant and benign brain tumors, vascular malformations, and trigeminal neuralgia. Gamma knife surgery is a low-risk, safe, and cost-effective non-invasive therapeutic option.

What Are the Advantages of Gamma Knife Therapy?

The gamma knife combines data from three-dimensional computer imaging studies with a stereotactic head frame to precisely target radiation. It can kill, stop, or shrink tumors, cause lesions to degrade, shut arteriovenous malformations, and modify the conducting pain fibers in trigeminal neuralgia patients. During treatment, the patient is provided with a stereotactic head frame, which acts as a measuring reference and helps hold the head in a stable position to ensure optimal comfort. The patient has been treated with 192 Cobalt 60 sources. The gamma rays converge at the target location, causing no harm to the surrounding healthy tissue. This finely targeted radiation only targets the lesion, leaving healthy tissue alone.

What Is the Difference Between Conformal Radiotherapy and Gamma Knife?

3D-Conformal Radiotherapy-

• Non-invasive, painless treatment approaches allow patients to recline comfortably while the equipment, such as a robotic arm, open bore, or gantry, moves quickly around them.

• Radiotherapy machines are highly specialized systems that can precisely target tumors in the brain, neck, skull, and spine from over 1,300 different locations.

• In one to five radiation sessions, radiotherapy equipment can treat cancer anywhere on the body.

• Radiotherapy devices provide a superior outcome because of enhanced accuracy during treatment. In addition, in 2001, the FDA approved radiotherapy equipment for treating malignancies across the body.

Gamma Knife-

• Before and during treatment, a massive metal frame must be fastened onto the patient's head.

• The gamma knife is a gantry device with up to 190 spots.

• The gamma knife can only cure brain or cervical spine cancer with single high-dose radiation therapy.

• The gamma knife has been used since the 1950s and has accumulated more results and benefits.

Conclusion:

Conformal radiation therapy generates radiation beams that precisely match the contour of a tumor. Previously, radiation beams were solely tailored to the height and width of a tumor. Conformal radiation therapy directs these beams to the exact site of the tumor, minimizing adverse effects on surrounding healthy tissue. Depending on the size and shape of the tumor, this approach enables larger doses of radiation to be delivered to it. 3D conformal radiation therapy is advantageous in emergencies because the treatment setup time is lower than other types of radiation therapy, and the treatment is faster.