Radiation therapy uses high-energy rays to damage cancer cell DNA. This targeted approach aims to destroy the tumor while minimizing exposure to surrounding healthy tissues. Understanding the sequential steps of this treatment, from initial preparation to post-treatment recovery, can help demystify the process. The therapeutic journey involves meticulous preparation, brief daily sessions, proactive management of physical changes, and long-term medical follow-up.
Treatment Planning: Setting the Stage
The radiation process begins with a consultation with a radiation oncologist. The patient then undergoes simulation, a preparation step for the actual treatment. During simulation, a computed tomography (CT) scan is performed with the patient positioned exactly as they will be for every treatment, sometimes using specialized magnetic resonance imaging (MRI) or positron emission tomography (PET) scans.
Custom immobilization devices (e.g., body molds or head masks) are created to ensure consistent daily positioning. The therapist applies tiny, permanent marks (tattoos) or temporary markings on the skin. These external reference points allow the treatment team to precisely align the radiation beam to the tumor target.
Simulation data is transferred to a treatment planning system. A medical dosimetrist and physicist work with the oncologist to calculate the exact radiation dose and beam angles. This process, known as dosimetry, designs a three-dimensional map maximizing radiation to the tumor while sparing nearby organs. The final plan requires team approval before daily sessions begin.
The Daily Treatment Session
Daily sessions typically run five days a week for several weeks. The actual time on the treatment table is usually short (10 to 30 minutes). Most of this time is dedicated to precise patient positioning, verified using skin marks and sometimes daily imaging taken on the machine.
The radiation therapist uses lasers and skin marks to align the body with the treatment machine (often a linear accelerator). The patient must lie completely still during the treatment. The therapist operates the machine from a shielded control area, monitoring the patient constantly through a video camera and intercom system.
The machine may rotate to deliver radiation from multiple angles, producing a loud buzzing or clicking sound, but the patient feels nothing. External beam radiation therapy does not leave a radiation source in the body. Once the machine is off, the patient can safely leave the room with no risk of radiation exposure to others.
Managing Common Physical Changes
Radiation therapy affects healthy cells, leading to acute physical changes. The most common systemic effect is generalized fatigue, which becomes more noticeable toward the end of treatment. Patients manage tiredness by prioritizing rest and incorporating light physical activity, such as short walks.
Localized side effects depend on the body part treated. Skin reactions are frequent, often starting a couple of weeks into treatment. Radiation dermatitis can manifest as:
- Redness
- Dryness
- Itching
- Peeling, similar to a sunburn
Gentle skin care involves washing the area daily with mild, unscented soap and warm water, patting the skin dry, and applying physician-recommended moisturizers.
Patients must avoid irritating the treated skin by:
- Wearing loose-fitting clothing
- Protecting the area from sun exposure
- Avoiding heat
- Avoiding cold, including heating pads or ice packs
Head and neck treatments may cause mucositis (mouth and throat sores) and changes in taste. Abdomen or pelvis radiation can cause nausea, managed with anti-nausea medications, or diarrhea, eased by dietary adjustments.
Recovery and Follow-Up Care
Acute side effects usually peak during the final week of treatment or shortly after completion. Most acute symptoms, including fatigue and skin reactions, subside a few weeks to a few months after the last session. Skin darkening may persist temporarily, and the skin will remain sensitive to sun exposure long-term.
After therapy completion, patients enter medical surveillance, with the first follow-up appointment scheduled within a few weeks. These visits allow the radiation oncologist to assess side effect resolution and monitor recovery. Diagnostic tests (e.g., blood work or imaging scans) may be ordered periodically to check the treated area.
Follow-up care is a long-term commitment, with visits gradually decreasing over time. Patients are monitored for potential late effects—changes that occur months or years after treatment, such as tissue scarring or changes in organ function. The care team collaborates with other specialists to manage any long-term issues proactively.