Radiation therapy overview

Radiation therapy (radiotherapy for short) is a cancer treatment that uses high-energy rays (such as X-rays, gamma rays or proton beams) to destroy the DNA of cancer cells, inhibit their growth or directly kill cancer cells. As one of the three main methods of cancer treatment (the other two are surgery and chemotherapy), radiotherapy can be divided intoexternal radiation(like a linear accelerator) andinternal irradiation(such as radioactive seed implantation). Its core advantage lies in precisely targeting tumor tissue and reducing damage to normal cells. Radiotherapy is often used as postoperative adjuvant treatment, palliative care for advanced patients, or as a radical means (such as early-stage laryngeal cancer). In terms of technological development, traditional two-dimensional radiotherapy has advanced toThree-dimensional conformal radiotherapy (3D-CRT),Intensity modulated radiotherapy (IMRT)and other precise solutions.

Principles and techniques of radiotherapy

Radiotherapy uses free radicals generated by ionizing radiation to destroy the double strands of DNA in cancer cells, making them unable to replicate. Modern technology such asStereotactic Radiosurgery (SRS)Achieves sub-millimeter accuracy and is suitable for brain tumors;proton therapyThe Bragg peak effect is used to concentrate energy deep in the tumor and reduce peripheral damage. In terms of equipment, common ones include:

Clinical applications and indications

Radiotherapy is suitable for a variety of cancers, such as breast cancer (postoperative adjuvant), lung cancer (radical cure or symptom relief), and prostate cancer (radioactive seed implantation). According to different purposes, they are divided into:

• radical radiotherapy: Early cervical cancer, nasopharyngeal cancer, etc.;
• adjuvant radiotherapy: Remove residual cancer cells after surgery;
• palliative radiotherapy: Relieve bone metastasis pain or compression symptoms.

famous oncologistHenry S. KaplanZeng pointed out: "The precision of radiotherapy is the key to improving the efficacy." Currently, about 50% of cancer patients will receive radiotherapy during the course of the disease.

Side effects and risk management

Radiation therapy can cause short-term side effects (such as skin redness, fatigue) and long-term risks (such as tissue fibrosis or second cancers). PassImage Guided Radiation Therapy (IGRT)andrespiratory gating technologyCan reduce errors. Patients need to be reviewed regularly, and nutritional support (such as a high-protein diet) can help with recovery. Data from the MD Anderson Cancer Center in the United States show that modern technology has reduced the incidence of serious side effects to less than 10%.

Summary and Outlook

Radiation therapy has developed over a century, from Marie Curie's radium therapy to today's proton therapy, with significant improvements in accuracy and safety. future,Artificial intelligence target area delineationandFlash radiotherapy(Ultra-high-speed irradiation) may become a new direction. When selecting a patient, it is necessary to consider the condition, technical availability and doctor’s advice to achieve individualized treatment.

Citing sources

1. National Cancer Institute (NCI) "Radiation Therapy for Cancer"
2. World Health Organization (WHO) "Cancer Radiotherapy Guidelines"
3. Varian Medical Systems official website product information (Varian Medical Systems)
4. The classic book on oncology "Principles and Practice of Radiation Oncology" (Author: Phillips TL)