What is Megavoltage imaging?
Megavoltage (MV) X-ray beams generated from a linear accelerator are commonly used to deliver the prescribed radiation dose to the tumor while minimizing the dose to the surrounding healthy tissues. The geometric accuracy of such treatment is crucial for its success.
What is Megavoltage used for?
Megavoltage x-rays are preferred for treatment of deep lying tumours as they are attenuated less than lower energy photons, and will penetrate further, with a lower skin dose. Megavoltage x-rays also have lower relative biological effectiveness than orthovoltage x-rays.
What is Obi imaging?
On-board imaging (OBI) is an innovative technique that uses images to confirm that a patient’s radiation therapy setup accurately reflects the patient’s treatment plan. Immediately prior to each treatment session, a radiation therapist uses a built-in CT scanner to take a series of images of the patient’s tumor.
What is Megavoltage unit?
Megavoltage Radiation Therapy (MRT) Unit – A linear accelerator, cobalt unit, particle accelerator or other piece of medical equipment operating at an energy level equal to or greater than 1.0 million electron volts (megavolts or MeV) for the purpose of delivering doses of radiation to patients with cancer, other …
What is a deep xray?
Orthovoltage X-rays are sometimes termed “deep” x-rays (DXR). They cover the upper limit of energies used for diagnostic radiography, and are used in external beam radiotherapy to treat cancer and tumors. They penetrate tissue to a useful depth of about 4–6 cm.
What is Epid in radiotherapy?
The electronic portal imaging device (EPID) is used for patient setup during radiotherapy sessions. Dosimetric verification is done using ion chambers, diodes and thermoluminescence detectors. In intensity-modulated radiation therapy (IMRT) the dosimetry is a sophisticated and time-consuming task.