What is Radiation Treatment?
 
 
 
treatment offered    
 

DIFFERENT TYPES OF RADIOTHERAPY:

2D (2 DIMENSIONAL) RADIOTHERAPY:
Traditionally; the planning of Radiation Treatments has been done in Two Dimensions (2-D). It mainly consists of a single beam of Radiation delivered to the patient from several directions: often front or back, and both sides.  The worry is that some high-dose treatments may be limited by the Radiation Toxicity capacity of healthy tissues which are close to the target tumor volume. For this reason, 3-dimensional conformal Radiotherapy is becoming the standard treatment for a number of tumor sites.  

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3D (3 DIMENSIONAL) CONFORMAL RADIATION THERAPY:
Conformal Radiation Therapy uses computer technology to allow doctors to more precisely target a tumor with Radiation Beams (using width, height, and depth). A 3-D image of a tumor can be obtained using Computed Tomography (CT), Magnetic Resonance Imaging (MRI), Positron Emission Tomography (PET), or Single Photon Emission Computed Tomography (SPECT).

Localization of the disease and normal organs in Three Dimensions is the prerequisite to carry out such a treatment plan with three-dimensional treatment planning, treatment delivery verification, and plan documentation.

Patient is immobilized to deliver the treatment. After the immobilization the patient is simulated on the Radiotherapy Simulator. CT scan is then taken in the treatment position (also known as CT Simulation) with immobilization mask and the entire area is scanned at 3-5-mm intervals. The images from the scan are transferred to a treatment planning computer via DICOM networking, and the physician traces the outline of the tumor and normal organs on each slice of the CT scan. The treatment planning computer allows the physician to try different beam arrangements on the patient, a process known as Virtual Simulation. The treatment planning computer may show the beam's eye view (BEV), which is a visual depiction of the treatment field in relation to the tumor and the bony anatomy of the patient and normal organs. Using information from the BEV, physicians can design custom blocking of parts of the Radiation beam in order to spare normal tissue as much as possible, which allows doctors to give the highest possible dose of Radiation to the tumor. Digitally Reconstructed Radiographs (DRR) are used for verifying the treatment position. This is followed by transfer of the treatment parameters to treatment machine. Online portal imaging (EPID-Electronic Portal Imaging Device) is used to verify that treatment is delivered exactly as planned.

Using information from the image, special computer programs design radiation beams that conform to the shape of the tumor. Because the healthy tissue surrounding the tumor is largely spared by this technique, higher doses of radiation can be used to treat the cancer. In other words it is a technique in which the prescribed dose volume is made to conform closely to the target volume in three dimensions. It delivers the radiation dose to the cancerous area with adequate margins and at the same time minimizes the dose to the normal surrounding tissues. Improved outcomes with 3-D conformal radiation therapy have been reported for nasopharyngeal, prostate, lung, liver, and brain cancers.

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Intensity- modulated radiation therapy (IMRT).
IMRT is a new type of 3-D conformal Radiation Therapy that uses Radiation beams (usually x-rays) of varying intensities to deliver different doses of radiation to small areas of tissue at the same time. It evolved from the inability of 3D CRT to irradiate tumors that are concave, surrounded by normal tissue, or in very close proximity to sensitive normal tissue, without causing excessive Radiation exposure of adjacent normal tissue.

The Technology allows for the delivery of higher doses of Radiation within the tumor and lower doses to nearby healthy tissue. Some techniques deliver a higher dose of Radiation to the patient each day, potentially shortening the overall treatment time and improving the success of the treatment. IMRT may also lead to fewer side effects during treatment.

It delivers an especially non-uniform radiation exposure to patient to create a uniform dose distribution at the target site. The treatment is delivered by using Multi Leaf Collimators (MLC) or Physical Modulator (compensating filter) mounted on a Linear Accelerator.

All types of cancer are treated with the Intensity-Modulated Therapy. CNS cancer, Head and Neck Cancer, Breast Cancer, Lung Cancer, Pancreatic Cancer, Esophagus Cancer and Prostate cancers are some of the cancer successfully treated with the technique. IMRT requires highly skilled staff and sophisticated machines.

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IGRT - Image Guided Radiation Therapy
Standard Radiation Therapy is limited in many cases by normal shifts within human anatomy. Tissues and organs can settle around the bones differently each time a patient climbs onto the treatment table. Patients may gain or lose weight over the course of 25 to 35 daily treatments, causing repositioning of organs. Tumors can move several centimeters as patients breathe during treatments. Oncologists have had to compensate for tumor movements by making the radiation beam larger, exposing a significant volume of healthy tissue around the tumor. Unfortunately, to avoid causing complications in the surrounding healthy tissue, the radiation doses have had to be limited—sometimes to a point below the optimal amount needed to kill the tumor.

Using IGRT, clinicians typically verify tumor locations on a daily / weekly basis, often using the high-energy treatment beam to generate an image that can be used to make any needed adjustments in patient positioning and treatment plans.

IGRT maps (image Gating) the exact position of the tumor and helps doctors deliver precise treatment sparing the surrounding healthy cells even during body movements like breathing when the tumor moves and is not static.

IGRT using real-time imaging techniques helps doctors locate and target moving tumors with unprecedented accuracy. It combines a new form of scanning technology, which allows online imaging using cone beam CT with IMRT. This enables physicians to adjust the radiation beam based on the position of the target tumor and critical organs, while the patient is in the treatment position. 

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The patient lies on a treatment couch under a medical Linear Accelerator. He is ready to receive his daily dose of radiation. A cone beam CT scan is taken taking images to pinpoint the tumor’s exact location. In a control room, clinicians monitor computers that match the images with the patient’s treatment plan to see if the tumor has shifted. It has. Within seconds, the coordinates needed to put the tumor into perfect alignment with the radiation beam are calculated. Then, with the push of a button, the therapists adjust the couch and position the patient for treatment. The On-Board Imager device verifies accurate hitting of the target and avoiding surrounding critical structures.

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BRACHYTHERAPY
Keeping the Radioactive material close to or inside the tumour is called Brachytherapy; unlike the linear accelerator treatment where the radiation beam is directed from quite far from the body
 
Generally it is used for the Tongue implant, Breast Implant, Esophagus and Lung cancer. Besides these soft tissue sarcomas (Intra Operative Implant), Carcinoma Prostate, Paediatric solid tumors (Rhabdo Myosarcoma), Carcinoma Nasopharynx, Buccal mucosa and carcinoma penis, Surface Moulds for are some of other applications of Brachytherapy. It is especially helpful for conservation of the organ afflicted with cancer for better functional and cosmetic results.

The treatment is given with machine Flexitron remote after loading HDR. The applicator is inserted into the body for the treatment. The applicator is linked to the main source through connecting tubes. The number of connecting tubes, time duration, and area to be treated is all decided with the help of treatment Planning computers (Flexiplan) and transferred via networking to the treatment machine.

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