Radiotherapy |
Radiotherapy is the main stay of treatment for most of the solid tumors. About 70%-80% of patients require radiotherapy either alone or in combination with surgery and /or chemotherapy. Radiotherapy may be curative, adjuvant and palliative. |
| The medical Linear Accelerator produces higher-energy x-rays that can penetrate deeper into tissue and reduce dose to skin. The linear accelerator uses high-frequency electromagnetic waves to accelerate electrons to high energy through a microwave accelerator structure. The high-energy electron beam itself can be used for treating superficial tumors or it can be made to strike a target to produce an x-ray beam for treating deep-seated tumors. |
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The Multileaf collimator facilities the use of complex three-dimensional treatment plans. The Multileaf collimator contains multiple pairs of thin leaves (usually 20 to 40) that attenuate the beam. Since each leaf can be moved independently of the others, a field of any shape can be rapidly created eliminating the time required to reenter the treatment room and insert customized beam-shaping blocks. |
Three-dimensional (3-D) conformal radiation therapy. |
Traditionally , the planning of radiation treatments has been done in two dimensions (3-d) conformal radiation therapy uses computer technology to allow doctors to more precisely target a tumor with radiation beams (using width, height, and depth). Many radiation oncologists use this technique. 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).
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. Improved outcomes with 3-D conformal radiation therapy have been reported for nasopharyngeal, prostate, lung, liver, and brain cancers. |
Intensity- modulated radiation therapy (IMRT).
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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. 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.
The radiation is delivered by a linear accelerator that is equipped with a multileaf collimator (a collimator helps to shape the beams of radiation). The equipment can be rotated around the patient so that radiation beams can be sent from the best angels. The beams conform as closely as possible to the shape of the tumor. Because IMRT equipment is highly specialized, not every radiation oncology center uses IMRT. |
CT Simulator with integrated 3D Treatment Planning System)
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| Hemalata Hospitals and Research Centre, Bhubaneswar has the proud privilege of installing India's first integrated CT Simulator with 3D treatment planning system, that was inaugurated by Dr.APJ Abdul Kalam., president of India on the 27th December 2005.
Once it is decided that the patient is to be given Radiotherapy, the first job is to simulate the treatment by the CT simulator and then the treatment is planned with the 3D treatment planning system. CT simulation is done by positioning the patient in exactly the same condition in which the treatment will be delivered in the Linear Accelerator. The process gives a digital model of the patient with the tumor and other critical structures marked by the specialists. Then the treatment planning system uses the machine parameters to optimally plan the treatment and transfers the final and approve plan to the Linear Accelerator computer which delivers the treatment. |
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