3Dimentional Confirmal Radio Therapy

 

Laxamma a 60yr old patient presented to me with a diagnosis of carcinoma cervix. When I told her that she needs treatment with radiotherapy she was taken by surprise as the term radiotherapy was very new to her. She had no idea what is radiotherapy and how is it going to be delivered etc. It added to her problems more as the diagnosis of cancer was a surprise for her and now a new type of treatment is announced. That incident prompted me to write down regarding radiotherapy emphasizing on the common questions that are asked by patients regarding radiation therapy.

What is Radiation Therapy/ Radiotherapy?

Radiation therapy is use of high energy ionizing radiation to kill cancer cells.  X Ray , Gamma Ray and Charged particles are the types of radiation used for killing cancer cells. The Radiation may be delivered by a machine out side the body called External Beam Radiotherapy. It is called Brachytherapy if the sourse of radiation is placed within the body near the cancer cells. Systemic Radiation may be given by radioactive substances like radioactive iodine which travel in the blood to kill the cancer cells.

How does Radiation Therapy kill Cancer cells?

Radiation Therapy kills cancer cells by damaging the DNA which caries genetic information for the survival and further generation of cells. When the cancer cells die after being repeatedly attacked by ionizing radiation they are eliminated from the body.

How is Radiation therapy used for treatment?

Radation therapy can be used as a

• Primary curative modality of treatment
• Adjuvant radiation therapy: To prevent disease from coming back after primary modality of treatment like surgery or chemotherapy.
• Neoadjuvant Radiation therapy: Before the primary modality of treatment like surgery to decrease the tumor burden to achieve better surgical clearance.

How is radiation therapy planned for an individual patient?

Treatment Planning is the process where the radiation oncologist decides the course of the treatment and is stated with immobilization. The patient need to be completely stable and in the same position daily so as to have accurate treatment at the same place everyday. A cast is made around the part of the body to be treated and then the patient is taken for scanning with the cast. As desired the CT Scan and MRI scan are done to localize the exact area of treatment.

After the imaging the radiation oncologist determines the area to be treated and the area that is needed to be saved from the harmful effects of radiation therapy. The radiation oncologist prescribes the dose of radiation to the tumor and also the maximum permissible dose to the normal structures surrounding the tumor. In every 3mm of the CT scan the volumes are drawn on the computer and then the team of radiation physicists do the radiation planning.

What are the factors that affect radiation therapy?

• Radiation therapy is decided by the radiation oncologist based on following The type of cancer. The size of the cancer.
• The cancer’s location in the body.
• How close the cancer is to normal tissues that are sensitive to radiation.
• How far into the body the radiation needs to travel.
• The patient’s general health and medical history.
• Whether the patient will have other types of cancer treatment.
• Other factors, such as the patient’s age and other medical conditions.
• History of previous treatments for cancer like surgery, chemotherapy or radiation therapy.

What are the different machines used in Radiotherapy?

The radiation therapy can be delivered by Cobalt machine or Linier accelerator. The cobalt machine has been used for the treatment of cancer since long. It uses Co60 as the source and emits gamma rays for the treatment of radiation.

Linier accelerator is the radiotherapy treatment machine which emits X rays and electrons for the radiation treatment. There has been tremendous development in the linier accelerator and the evolution has brought different techniques for more precise and accurate treatment.

What is 3D CRT radiotherapy Technique?

3D CRT technique: 3D-CRT uses very sophisticated computer software and advanced treatment machines to deliver radiation to very precisely shaped target areas. In 3D CRT we can use computer assisted planning to design the beam angles and modify the dose through every beam to bet shaped target. Disadvantage of 3D CRT over higher technique is the dose delivered by individual beam can not be modified hence it ends up in giving some radiation to normal structures.

What is Intensity-modulated radiation therapy (IMRT): A Revolutionary Concept

IMRT uses hundreds of tiny radiation beam-shaping devices, called collimators, to deliver a single dose of radiation. The collimators can be stationary or can move during treatment, allowing the intensity of the radiation beams to change during treatment sessions. This kind of dose modulation allows different areas of a tumor or nearby tissues to receive different doses of radiation Unlike other types of radiation therapy, IMRT is planned in reverse (called inverse treatment planning). In inverse treatment planning, the radiation oncologist chooses the radiation doses to different areas of the tumor and surrounding tissue, and then a high-powered computer program calculates the required number of beams and angles of the radiation treatment. In contrast, during traditional treatment planning (3D CRT) the radiation oncologist chooses the number and angles of the radiation beams in advance and computers calculate how much dose will be delivered from each of the planned beams

The goal of IMRT is to increase the radiation dose to the areas that need it and reduce radiation exposure to specific sensitive areas of surrounding normal tissue. Compared with 3D-CRT, IMRT can reduce the risk of some side effects, such as damage to the salivary glands (which can cause dry mouth, or xerostomia), when the head and neck are treated with radiation therapy.

What is  Image-guided radiation therapy (IGRT)?

Image-guided radiation therapy (IGRT): In IGRT, repeated imaging scans (CT, MRI, or PET) are performed during treatment. These imaging scans are processed by computers to identify changes in a tumor’s size and location due to treatment and to allow the position of the patient or the planned radiation dose to be adjusted during treatment as needed. Repeated imaging can increase the accuracy of radiation treatment and may allow reductions in the planned volume of tissue to be treated, thereby decreasing the total radiation dose to normal tissue

What is Rapid Arc Technique of Radiotherapy?

 

 

 

 

 

 

 

RAPID ARC delivers radiation by rotating the gantry of a linac through one or more arcs with the radiation continuously on. RAPID ARC provides uncompromised treatment in two minutes or less. Researchers have found that RapidArc compares favorably with conventional IMRT and IGRT planning for a variety of clinical sites.

What is On Board Image Guidance?

The state of the art radiotherapy machine is equipped with X Ray and Cone beam CT Scan (CBCT) which helps in taking image of the patient before treatment. This helps in image guidance and results in high accuracy of radiation treatment.

What is Internal radiation therapy (Brachytherapy)?

Internal radiation therapy (brachytherapy) is radiation delivered from radiation sources (radioactive materials) placed inside or on the body In brachytherapy, radioactive isotopes are sealed in tiny pellets or “seeds.” These seeds are placed in patients using delivery devices, such as needles, catheters, or some other type of carrier. As the isotopes decay naturally, they give off radiation that damages nearby cancer cells. In today’s era the placement of sourse and its dose distribution is completely computer guided and helps in minimal dose to normal tissue sounding the tumor.

http://www.brachytherapy.com/#prettyPhoto

What is Systemic radiation therapy?

Patient is injected with radioactive substance and it circulates in the blood to attack the cancer cells. For example radioactive iodine is used for treatment of thyroid cancers.

Why is radiation therapy not given in single dose rather delivered in small doses for a long period of time like a month?

Patients who receive most types of external-beam radiation therapy usually have to travel to the hospital or an outpatient facility up to 5 days a week for several weeks. One dose (a single fraction) of the total planned dose of radiation is given each day. Occasionally, two treatments a day are given.

Most types of external-beam radiation therapy are given in once-daily fractions. There are two main reasons for once-daily treatment:

• To minimize the damage to normal tissue.
• To increase the likelihood that cancer cells are exposed to radiation at the points in the cell cycle when they are most vulnerable to DNA damage.

Does radiation therapy make a patient radioactive?

Patients on external beam radiation are not radioactive and they can comfortably mix with all family members.

Patients on systemic radiotherapy like iodine treatment will be radioactive for few days and they need to be kept islated during that period.

How is Queens NRI hospital Vishakhapatnam (Vizag) in terms of Radiotherapy?

Vishakhapatnam has been a very important place as far as health care is considered but unfortunately it has been lacking the best of the technologies. The patients from Vishakhapatnam, nearby places of Andhra Pradesh and Odisha had to go to far off places like Hyderabad and Mumbai to get treatment. With the aim to provide modern state of the art technology to the cancer patients we have installed the Radiation machine with the latest technique. We are the pioneers in providing the radiotherapy with RAPID ARC, Image Guided radiotherapy (IGRT), Intensity Modulated radiotherapy (IMRT) in this part of Andhra Pradesh at an affordable price.

We are the first institute in the coastal Andhra to have acquired the latest machine Varian Rapid Arc Linear Accelerator equipped with most sophisticated 3D Planning and Dosimetry systems. We use the fusion of CT scan, MRI scan to exactly delineate the cancer tissue and also to protect the surrounding normal tissue. The machine is equipped with inbuilt CT scan and X Ray Machine which verify the treatment every day with millimeter accuracy.

Radiation oncology services provided:

• External Beam Radiotherapy using state of the art linear accelerator
  • High definition RAPID ARC
  • Image Guided radiotherapy (IGRT)
  • Intensity Modulated radiotherapy (IMRT)
  • Three Dimensional (3D) Conformal Radiotherapy
  • Electron Radiotherapy
• Brachy Therapy (Internal radiation)

What is Tumor Board and how does it make a difference in Cancer care?

Tumor board is a meeting participated by all the doctors concerned in cancer treatment i.e. radiation oncologist, Surgical Oncologist, Medical Oncologist, Radiologist, Pathologist, Gastroenterologist, Surgeon, Urologist, Neurosurgeon etc. Here all the cases are discussed and the final treatment Is decided in discussion with everyone. Tumor board helps us to maintain highest quality of treatment with complete scientific basis. In Vishakhapatnam queens NRI hospital is the only hospital to conduct regular tumor board assuring a comprehensive cancer care to all its patients.

The institute is committed to provide comprehensive cancer care utilizing the latest approved international guidelines. We emphasize on delivering personalized care to every patient. The latest technology with the best trained medical personnel with all the facility available under one roof and at an affordable price makes our institute a prudent choice for any patient or physician seeking comprehensive cancer treatment.

 

 

Related articles

• Comparative effectiveness, radiation therapy, and prostate cancer treatment (prostatecancerinfolink.net)