Radiation therapy is one of the main treatment methods used in cancer care. It uses controlled doses of high-energy rays to damage the DNA of cancer cells so that they stop growing or die over time. Healthy cells can also be affected, but they usually repair themselves better than cancer cells. This difference allows radiation to be used safely when it is carefully planned and delivered. Radiation is a key part of many advanced cancer treatments and is often combined with surgery or medical oncology services such as chemotherapy and targeted therapy.
Broadly, radiation therapy is delivered in two principal ways, also called radiation therapy types:
- External Beam Radiation Therapy (EBRT) – radiation comes from a machine outside the body and is directed towards the tumor from different angles.
- Internal Radiation Therapy (Brachytherapy) – a small radiation source is placed inside the body, in or very close to the tumor.
Both approaches are used in modern cancer care at a comprehensive radiation oncology hospital in India. An experienced oncologist in India will decide which method, or combination of methods, is best suited to each patient’s disease and overall condition. In some cases, radiation is used along with surgery, including modern options like robotic cancer surgery, and systemic medical oncology services to build a complete, multi-disciplinary treatment plan.
What is External Beam Radiation Therapy (EBRT)?
External beam radiation therapy is the most commonly used form of radiation. A machine placed outside the body generates high-energy X-rays or other beams and directs them to a defined target inside the body.
The most frequent device used is a linear accelerator (LINAC). During treatment, the patient lies on a treatment table in a precise position. The machine rotates around the patient to deliver radiation from multiple angles, based on a pre-planned path. The machine does not touch the patient during treatment.
When EBRT is used
EBRT is used for many types of solid tumors, including:
- Brain and spinal tumors
- Head and neck cancers
- Breast cancer
- Lung and esophageal cancers
- Prostate and bladder cancers
- Rectal and anal cancers
- Some bone and soft-tissue tumors
It can be given:
- With the intent to cure cancer
- Before surgery to shrink a tumor
- After surgery to destroy any remaining cancer cells
- To relieve symptoms such as pain, bleeding, or pressure
EBRT is often part of advanced cancer treatments, especially when high precision and organ preservation are important.
Planning and delivery of EBRT
Clinical assessment and counseling
A radiation oncologist in India reviews the medical history, biopsy report, imaging, and overall health, and discusses the role of radiation in the treatment plan.
CT simulation (planning scan)
The patient undergoes a CT scan in the treatment position. Immobilization devices (for example, a head mask or body mold) may be used to help maintain the same position daily. Small skin marks or tiny tattoos help with accurate alignment.
Treatment planning
Using specialized computer software, the team outlines the tumor and nearby normal organs on the CT images. They design radiation beams so that a higher dose reaches the tumor while limiting dose to critical organs.
Daily treatment sessions (fractions)
Radiation is usually delivered in small doses over several sessions, often 5 days per week for a few weeks, depending on the diagnosis and protocol. Each session typically lasts 10–20 minutes. The patient does not feel the radiation. The team monitors the patient from an adjacent room and can communicate throughout the procedure.
Types of EBRT techniques
These techniques are examples of radiation therapy types used in EBRT:
- 3D-CRT (three-dimensional conformal radiation therapy):
Beams are shaped to match the three-dimensional outline of the tumor based on the CT scan. - IMRT/VMAT (intensity-modulated techniques):
Many small beam segments with varying intensity are used. This allows a high dose to the tumor while sparing nearby healthy tissue. - IGRT (image-guided radiation therapy):
Imaging (X-ray, cone-beam CT, or other methods) is done before or during treatment to confirm accurate positioning each day. - SRS/SBRT (stereotactic techniques):
Very precise, high-dose radiation delivered in 1 to 5 sessions for small, well-defined tumors (for example, certain brain, lung, liver, or spine lesions).
Possible side effects of EBRT
Side effects depend on the area treated, the total dose, and the patient’s general health. Common effects include:
- Fatigue
- Skin changes in the treated area (redness, dryness, darkening)
- Mouth or throat discomfort for head and neck treatments
- Cough or shortness of breath for chest treatments
- Changes in bowel or bladder habits for pelvic treatments
Most side effects are temporary and can be managed with skin care, medicines, dietary changes, and supportive measures advised by the care team.
Importantly, external radiation does not make the patient radioactive. It is safe to be around other people, including children and pregnant women.
What is Internal Radiation Therapy (Brachytherapy)?
Internal radiation therapy, or brachytherapy, involves placing a small radiation source inside the body, directly into or very close to the tumor. Because the source is near the target, the tumor receives a high dose while nearby normal tissue receives a lower dose. Brachytherapy is one of the important radiation therapy types used in gynecologic, prostate, and some other cancers.
Types of brachytherapy
By duration:
- High-dose-rate (HDR) brachytherapy:
A strong radiation source is placed temporarily for a short time (minutes) during each session, then removed. The patient goes home after treatment. - Low-dose-rate (LDR) brachytherapy:
Small radioactive “seeds” are implanted permanently. They give off radiation slowly over weeks or months and then become inactive.
By placement:
- Intracavitary brachytherapy:
The radiation source is placed in a natural body cavity such as the uterus or vagina (commonly used for cervical or uterine cancer). - Interstitial brachytherapy:
Thin tubes or seeds are placed directly into the tissue, for example, in the prostate or certain head and neck regions.
When brachytherapy is used
Brachytherapy is frequently used in:
- Cervical, uterine, and vaginal cancers
- Prostate cancer
- Selected early breast cancers (partial breast brachytherapy)
- Some head and neck, skin, and soft-tissue tumors in selected patients
Brachytherapy may be given alone or in combination with EBRT. For example, in cervical cancer, EBRT is often followed by brachytherapy to fully treat the primary tumor.
What patients can expect during brachytherapy
- Pre-procedure imaging: MRI, CT, or ultrasound may be done to map the tumor and surrounding organs.
- Placement of applicators or catheters: These devices are inserted into the uterus, vagina, prostate, or other target area, often under anesthesia or sedation to ensure comfort.
- Treatment delivery: The patient is moved to a shielded treatment room. A computer-controlled machine connects to the applicators and sends the radiation source in and out according to a pre-planned schedule. The patient does not feel the radiation.
- Removal and recovery: For HDR brachytherapy, the source and applicators are removed after each session. Patients are then monitored and discharged as per protocol. For permanent seeds, the procedure is usually done in an operating room and patients go home later the same day.
Possible side effects of brachytherapy
Side effects depend on the organ treated and the dose:
- Local soreness or mild bleeding at the insertion site
- Temporary urinary or bowel changes in prostate or pelvic treatments
- Vaginal irritation or discharge in gynecologic treatments
Short-term effects are usually manageable with medicines and local care. The radiation oncology team will explain potential long-term effects specific to the treatment site.
After HDR brachytherapy, there is no radiation left in the body. After LDR seed implantation, radiation outside the body is very low. Simple safety instructions are provided, such as limiting prolonged close contact with small children or pregnant individuals for a limited period.
EBRT vs Brachytherapy: how the approach is chosen
The decision between external beam radiation therapy and brachytherapy is individualized. Factors considered include:
- Tumor type and stage:
Whether the cancer is localized or has spread influences the choice and combination of techniques. - Tumor size and location:
Tumors that can be accessed from inside the body (such as cervix or prostate) are often suitable for brachytherapy. Larger or more irregular tumors, or those near certain critical structures, may be better treated with EBRT, or with EBRT followed by brachytherapy. - Treatment goal:
Curative intent, disease control, or symptom relief may each require different strategies or dosing schedules. - Patient’s general health and preferences:
Fitness for anesthesia, ability to attend daily sessions, and personal circumstances are discussed. - Previous treatments:
Prior radiation in the same region or major surgery can affect what is safe and feasible.
A well-equipped radiation oncology hospital in India that offers a broad range of radiation therapy types as part of its advanced cancer treatments can combine EBRT, brachytherapy, surgery (including robotic cancer surgery where appropriate), and medical oncology services into a coordinated plan.
Conclusion
Radiation therapy is a precise and carefully planned treatment that can be delivered from outside the body (external beam) or from within (brachytherapy). Both techniques have important roles in modern cancer care, and the best approach is selected after detailed evaluation of the tumor, overall health, and treatment goals.
Within AOI cancer care, radiation is integrated with surgery and systemic therapy to build complete and individualized plans. If you have been advised radiation or want to understand the difference between various radiation therapy types, discuss them with your oncologist in India and clarify how they fit into your overall course of advanced cancer treatments. This understanding helps you take informed decisions and work with your team toward safe, effective, and well-coordinated care.