Radiation Therapy

What is radiation therapy? Radiation therapy is basically treatment with X Ray’s and gamma rays, mostly for cancerous conditions, although a few benign conditions are also treated with the help of this modality. How it administered and what are the common types? This treatment can be administered externally from outside the body or internally.The external treatment is administered on sophisticated machines known as linear accelerators or LINACS. The treatment is delivered in small fractions and my last from 2 to 7 weeks. Some patients may undergo internal radiation called brachytherapy. It is a form of treatment in which radiation is administered close to or into the tumor or the body. What to expect? Prior to the treatment, the patient undergoes a special procedure known as radiotherapy simulation. It is one of the most crucial steps and consists of a mould preparation for immobilization of the patient and subsequently a planning CT scan according to the sub site to be treated. The patient may be or may not be given intravenous and/or oral contrast. How is the treatment planned? Once simulation is done, planning is performed on CT simulation scan using a  specialized treatment planning system by a team comprising of radiation oncologists and medical physicists. First,  the tumor,  the areas at risk of tumor spread, and normal organs are marked  on the planning scan and plansaremade/generated by the physicists by using techniques such as 3D CRT, Intensity Modulated radiation therapy (IMRT), Rapid Arc, which are then evaluated and the best possible plan where in there is minimal dosage to the critical normal structures with appropriate tumor coverage is chosen. After planning, Quality assurance (QA) checks are performed by the medical physicists team, and when it is confirmed that the plan meets the established QA standards,  the patientbis called for treatment delivery. What are the expected side effects? Like every treatment, radiotherapy treatment also has its set of aide effects,  which are mostly documented and checked weekly. These vary according to the sub site being treated. Most common side effects of various sub sites include: Head & Neck:

• Nausea
• Loss of appetite
• Dryness of mouth
• Changes in taste
• Mouth ulcerations

Thorax

• Skin irritation, dryness, and darkening
• Swelling in the arm (lymphedema)
• Loss of hair in irradiated area
• Difficulty swallowing

Abdomen

• Nausea
• Loose motions
• Abdominal cramping

Pelvis

• Difficulty in passing urine/stool

Most of these effects are reversible and are managed with appropriate medication and interventions.   Dr Manoj Kumar Sharma Senior Consultant- Radiation Oncology