What Is Stereotactic Radiotherapy and How It Works? Pros and Cons

Stereotactic radiotherapy (SBRT) is an advanced form of radiation therapy that delivers highly precise, high-dose radiation to targeted areas of the body, such as tumors or other abnormalities, while minimizing exposure to surrounding healthy tissues. Unlike conventional radiation therapy, which typically involves treating larger areas over multiple sessions, SBRT focuses on delivering concentrated beams of radiation with pinpoint accuracy. This makes it particularly effective for treating small or well-defined tumors in locations such as the brain, spine, lungs, liver, or other organs.

The technology behind SBRT involves the use of imaging techniques like CT, MRI, or PET scans to create detailed, three-dimensional maps of the treatment area. These maps guide the radiation delivery system, ensuring that the beams are precisely aligned with the target. Sophisticated equipment such as linear accelerators (LINACs) or specialized systems like the Gamma Knife or CyberKnife are often used to perform SBRT. Depending on the condition being treated, SBRT can be delivered in a single session or across a few sessions, typically referred to as stereotactic radiosurgery (SRS) or fractionated stereotactic radiotherapy (FSRT).

What Is Stereotactic Radiotherapy?

Stereotactic Radiotherapy (SBRT) is a specialized form of radiation treatment that delivers highly focused radiation beams to tumors with remarkable precision. This technique minimizes exposure to surrounding healthy tissue, making it an effective option for treating various types of cancers, particularly those located in sensitive areas. By utilizing advanced imaging technologies, SBRT allows for the accurate localization and targeting of tumors, enhancing treatment effectiveness while reducing potential side effects.

SRT is particularly beneficial in addressing tumors that are challenging to reach through traditional surgical methods. It is often employed for tumors that are either inoperable or located near critical structures, where conventional surgery poses higher risks. This treatment modality is well-suited for small to medium-sized tumors, delivering concentrated doses of radiation that can lead to significant tumor shrinkage or even destruction.

How Does Stereotactic Radiotherapy Work?

The process involves several critical components that ensure accuracy and efficacy in treatment. The initial step in SBRT involves detailed imaging studies, typically utilizing CT and MRI scans. These imaging modalities provide a comprehensive view of the tumor’s location, size, and shape.

One of the defining features of SBRT is the use of multiple radiation beams directed from various angles toward the tumor. This approach allows for the convergence of radiation at the tumor site, maximizing the dose delivered to the cancerous tissue while effectively reducing the exposure of surrounding healthy structures. SBRT typically involves a series of treatment sessions, usually ranging from one to five, depending on the specific clinical scenario and the tumor being treated. Each session lasts only a short period, allowing for a more convenient treatment schedule for patients. The number of sessions is determined based on the type of tumor, its location, and the intended radiation dose.

source: brainlab.org

What Are the Types of Stereotactic Radiotherapy

There are several types of Stereotactic radiotherapy, including Stereotactic Radiosurgery (SRS), Stereotactic Body Radiation Therapy (SBRT), Stereotactic Ablative Radiotherapy (SABR).

Stereotactic Radiosurgery (SRS)

A non-invasive procedure that delivers a single, high dose of radiation to a targeted area. Commonly used for brain tumors, arteriovenous malformations (AVMs), and other intracranial conditions. The treatment is typically performed in one session, allowing for rapid recovery and minimal hospital stay. Precision is achieved through advanced imaging techniques, such as MRI or CT scans, ensuring accurate targeting of the tumor.

Stereotactic Body Radiation Therapy (SBRT)

A technique that delivers high doses of radiation over a limited number of sessions, usually between three to five. Primarily utilized for treating tumors located outside the brain, such as in the lungs, liver, and spine. SBRT employs sophisticated imaging to ensure precise localization of the tumor during each treatment session, accounting for any patient movement. This method is effective in managing early-stage cancers and can provide excellent local control of tumor growth.

Stereotactic Ablative Radiotherapy (SABR)

A specific form of SBRT, SABR is designed for treating tumors in various body locations with an emphasis on ablating or destroying the tumor. Similar to SBRT, it typically involves a few treatment sessions, with careful planning to minimize exposure to surrounding tissues. SABR is particularly useful for patients who are not candidates for surgery due to their overall health or tumor location. This approach is gaining popularity in treating primary and metastatic cancers in the lung, liver, and other areas.

Comparison of Stereotactic Techniques

All types rely on advanced imaging for tumor localization, improving radiation targeting. SRS typically involves a single session, while SBRT and SABR take three to five sessions. SRS is mainly used for brain tumors, whereas SBRT and SABR are applied to other body sites.

Stereotactic Radiosurgery (SRS)

Stereotactic Radiosurgery (SRS) delivers a concentrated radiation dose in one session, helping shorten treatment time while offering swift relief. This highly focused approach targets tumors or abnormalities in the brain and central nervous system with minimal impact on surrounding healthy tissues, which is crucial for preserving neurological function. To achieve such precision, MRI and CT scans are used to map the tumor’s exact location, ensuring the radiation is directed only where it is needed. SRS combines a rapid treatment schedule, pinpoint targeting, and sophisticated imaging to offer a potent way of managing brain lesions without invasive surgery.

SRS is commonly indicated for a variety of conditions, including

• Brain tumors, whether benign or malignant
• Arteriovenous malformations (AVMs)
• Metastatic cancer affecting the brain
• Certain functional disorders, such as trigeminal neuralgia

Recovery from SRS is generally quick, with many patients experiencing only mild discomfort or swelling and often returning to normal activities the next day. Serious complications are rare. Follow-up appointments focus on tracking recovery and evaluating treatment effectiveness, often including imaging studies a few months after the procedure to assess changes in the targeted area. Stereotactic Radiosurgery marks a major advancement in radiation therapy, providing a powerful treatment for difficult cases while preserving patient comfort and minimizing downtime.

Stereotactic Body Radiation Therapy (SBRT)

Stereotactic Body Radiation Therapy (SBRT) is designed to deliver high doses of radiation precisely to tumors located in various parts of the body, including the lungs, liver, and spine.

For certain patients, SBRT serves as a viable alternative to surgical intervention. It is particularly beneficial for those who may not be candidates for surgery due to underlying health conditions or the location of the tumor. SBRT offers a less invasive approach while maintaining a high success rate in controlling tumor growth.

Benefits of SBRT

• Reduced Recovery Time: Patients typically experience a shorter recovery period compared to traditional surgery, allowing them to quickly resume daily activities.
• Lower Risk of Complications: With less invasive techniques, SBRT reduces the likelihood of complications associated with surgical procedures, such as infection or longer hospital stays.
• Preservation of Function: By sparing healthy tissues, SBRT helps maintain organ function and minimizes the impact on patients’ quality of life.

Stereotactic Ablative Radiotherapy (SABR)

Stereotactic Ablative Radiotherapy (SABR) is an advanced cancer treatment that uses high radiation doses to target and eliminate small, localized tumors. By delivering concentrated doses in a few sessions, SABR achieves strong tumor control while sparing surrounding healthy tissue. Its precision makes it especially helpful for early-stage cancers, such as lung and prostate tumors, often serving patients who cannot undergo surgery. In lung cancer, SABR effectively manages small tumors, improving survival in cases where surgery is not an option. For prostate cancer, it delivers a high radiation dose directly to the prostate while preserving nearby tissue, providing a potent treatment with minimal side effects.

Benefits of SABR

• Shorter Treatment Course: Patients benefit from fewer treatment sessions, which can enhance compliance and reduce the burden of hospital visits.
• Minimal Side Effects: The precision of SABR helps in preserving healthy tissues, resulting in fewer side effects compared to conventional radiation therapy.
• High Success Rates: The effectiveness of SABR in achieving tumor control is reflected in high success rates, particularly for early-stage cancers.