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On this page I would like to tell more details about radiation therapy and would like to answer frequently asked questions

What is Radiation Therapy ?

Many forms of cancer can be treated with ionizing radiation. It can be delivered both internally and externally. The goal of all radiation therapy is to eradicate the tumor while limiting the radiation exposure to the surrounding healthy tissue. When treating with radiation, sophisticated treatment planning and dose calculations are made to deliver an effective and safe dose precisely to the targeted area. Radiation is a painless treatment and the patient experience is comparable to a chest XR or CT scan.

Who is candidate for radiation therapy ?

First the patient is evaluated by the radiation oncologist during the initial patient consultation. The patient is interviewed and examined. The medical records are reviewed including biopsy reports, staging workup results, CT, PET, MRI reports and films. The information is then summarized by the radiation oncologist and the recommendations are discussed with the patient and family members. If the patient is a candidate and is expected to benefit from radiation treatment, then the treatment planning, the treatment itself, the expected benefits and possible side effects are all discussed with the patient. During the initial consultation the radiation oncologist answers any questions the patient and family members may have.

How is the external beam radiation planned ?

First the patient is scheduled for treatment planning simulation that usually requires a contrast enhanced CT scan in the treatment position. To deliver an accurate treatment, the patient is positioned on the CT table using devices to help to maintain a reproducible and comfortable position for the duration of the CT-simulation and for the subsequent radiation treatment sessions that generally take only 10-20 minutes every day. The acquired CT images are then exported to the radiation treatment planning computer to allow the radiation oncologist to outline/contour the tumor and the surrounding normal organs. This is followed by the computerised treatment planning. Once the treatment plan is approved by the radiation oncologist then it is first verified on the treatment machine using a patient phantom. This is a very important quality assurance step to ensure maximum patient safety. Now the daily treatments can begin.

How is the actual external beam treatment is delivered ?

The patient is treated by well trained and dedicated radiation therapists who position the patient first on the treatment table in the poison established during the simulation using the same positioning devices, like braes board, vacuum bag, knee sponge, etc. Some patients will require more precise positioning to allow sub-millimeter accuracy of treatment delivery, in case when the tumors are close to vital or sensitive organs, like spinal cord or eyes, etc. Then the appropriate device is used, raging from custom made head mask to stereotactic-body-immobilization-table, etc, as deemed necessary by the radiation oncologist.

Then the positron is verified with wall mounted lasers, infra camera, on board imaging with kV XR or cone-beam-CT, as indicated. This takes 5-10 minutes. Once to position is optimal, then the actual radiation treatment is delivered in an additional 5-10 minutes. The radiation is a painless treatment and the patient experience is comparable to getting a chest XR or CT scan. The radiation is delivered from different directions using multiple radiation fields. The machine automatically adjust to different treatment angles slowly moving around the patient. It never comes too close to the patient. In the "head" of the machine there is a computer controlled field shaping device the multi-leaf-collimator (MLC). During each field of treatment the delivered dose is contoured around the shape of the tumor by the multi-leaf collimator (a device that consists of a number of moving “fingers” or “leaves”), that position themselves dynamically in order to block portions of the primary beam and create a desired shape and thus to minimize radiation dose reaching the normal tissues.

Once the treatment is delivered according to the plan, the patient is discharged home and will return next day for another treatment. Conventionally fractionated treatments are delivered daily over 2-9 weeks. High dose treatments that are usually referred to as stereotactic radiosurgical treatments (SRS) are delivered in 1-5 days only. During the weekly treatments the radiation oncologist re-evaluates the patient weekly or more often as indicated to manage any possible radiation related side effects. During SRS treatments, the patient is re-evaluated daily. Once the treatment is complete, the follow up plan and/or the additional treatment plan (surgery, chemotherapy) is discussed with the patient and family members as indicated.

The material appearing on this web site is for informational use only. It should not substitute for professional medical advice on diagnosis or treatment.



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