Cancer, which is the uncontrolled division of cells, a leading fatal disease in world with high mortality rates. It can be treated using several methods, including radiotherapy, involves ionizing radiation. Radiotherapy on basis source placement has two types, i.e. brachytherapy and external beam radiotherapy. External radiotherapy evolved from 2-D conventional therapy to 3-D Conformal (3D-CRT)...

Adverse effects and hazards which have their origin from radiation using conventional techniques like 3-D conformal radiotherapy and total radiation doses are well known. However little is known about the sprectum of especially late toxicity after radiation using new technologies like intensity modulated radiotherapy (IMRT) combined with novel target volume and dose concepts. Since IMRT allows ...

In this study, we present an intensity-modulated radiotherapy technique based on forward planning dose calculations to provide a concave dose distribution to the prostate and seminal vesicles by means of modified dynamic arc therapy (M-DAT). Dynamic arcs (350 degrees) conforming to the beam's eye view of the prostate and seminal vesicles while shielding the rectum, combined with two lateral obl...

The capability of the TrueBeam treatment system to deliver step and shoot IMRT plans at low dose rates was evaluated. Beam characteristics during low dose rates (5 to 100 MU/min) were evaluated for consistency using a planar ion chamber array. MU constancy, linearity, and beam profile symmetry were all found to be equivalent within 0.5%. The response of the Scandi Dos Delta 4 system was also ev...

Background: This study evaluates the dose distribution of the wedged tangential beam three-dimensionally planned conformal radiotherapy (3D-CRT) compared to the previously used (5 years ago) two-dimensionally (2D-RT) planned radiotherapy of the chest wall for postmastectomy breast cancer patients in Clinical Oncology and Nuclear Medicine Department, Mansoura University. Patients and Methods: Th...

The advent of intensity modulated radiotherapy (IMRT) provides an opportunity to spare critical normal tissue. For patients receiving radiotherapy for anal or rectal cancer, small bowel and the femoral heads can often be better protected with IMRT than conventional techniques. However, the technology also presents a challenge to the radiation oncologist. IMRT demands a much more detailed unders...

PURPOSE Adjuvant radiotherapy of breast cancer using a photon tangential field incurs a risk of late heart and lung toxicity. The use of free breathing (FB), expiration breath hold (EBH), and deep inspiration breath hold (DIBH) during tangential breast radiotherapy as a means of reducing irradiated lung and heart volume was evaluated. METHODS In 10 women with left-sided breast cancer (mean ag...

Intensity-modulated radiotherapy (IMRT) is a newer method of radiotherapy that uses intensity-modulated beams that can provide multiple intensity levels for any single-beam direction and any single-source position, allowing concave dose distributions and dose gradients with narrower margins than those possible using conventional methods. IMRT is ideal for treating complex treatment volumes and ...

A common way to solve intensity-modulated radiation therapy (IMRT) optimization problems is to use a beamlet-based approach. The approach is usually employed in a three-step manner: first a beamlet-weight optimization problem is solved, then the fluence profiles are converted into step-and-shoot segments, and finally postoptimization of the segment weights is performed. A drawback of beamlet-ba...