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...

Pagetoid reticulosis, also known as Woringer-Kolopp disease, is a rare variant of cutaneous T-cell lymphoma usually presenting as an isolated patch or plaque on the extremities. Immunohistochemical staining of T-cell markers can be variable, but as the name implies the epidermotropic lymphocytes consistently display a "pagetoid" appearance. The following case demonstrates clearance of this cond...

We designed and implemented a linear programming based IMRT treatment plan generation technology that effectively and efficiently optimizes beam geometry as well as beam intensities. The core of the technology is a fluence map optimization model that approximates partial dose volume constraints using conditional value-at-risk constraints. Conditional value-at-risk constraints require careful tu...

The use of intensity modulated radiation therapy (IMRT) has allowed for the administration of high doses to retroperitoneal sarcomas (RSTS) while limiting toxicity to adjacent organs. The purpose of our study is to assess the outcome and toxicities of patients with RSTS treated with neo-adjuvant external beam radiation (EBRT) therapy using IMRT. This is a retrospective study of 21 patients trea...

In this study, we perform a scientific comparative analysis of using (60)Co beams in intensity-modulated radiation therapy (IMRT). In particular, we evaluate the treatment plan quality obtained with (i) 6 MV, 18 MV and (60)Co IMRT; (ii) different numbers of static multileaf collimator (MLC) delivered (60)Co beams and (iii) a helical tomotherapy (60)Co beam geometry. We employ a convex fluence m...

The Guidelines Project, an initiative of the Brazilian Medical Association, aims to combine information from the medical field in order to standardize procedures to assist the reasoning and decision-making of doctors. The information provided through this project must be assessed and criticized by the physician responsible for the conduct that will be adopted, depending on the conditions and th...

The treatment of cancer of the anal canal has changed significantly over the past several decades. Although the abdominoperineal resection (APR) was the historical standard of care, a therapeutic paradigm shift occurred with the seminal work of Nigro, who reported that anal canal cancer could be treated with definitive chemoradiation, with APR reserved for salvage therapy only. This remains an ...

IMRT / 1 The American College of Radiology, with more than 30,000 members, is the principal organization of radiologists, radiation oncologists, and clinical medical physicists in the United States. The College is a nonprofit professional society whose primary purposes are to advance the science of radiology, improve radiologic services to the patient, study the socioeconomic aspects of the pra...

IMRT treatment planning via biological objectives gives rise to constrained nonlinear optimization problems. We consider formulations with nonlinear objectives based on the equivalent uniform dose (EUD), with bound constraints on the beamlet weights, and describe fast, flexible variants of the two-metric gradient-projection approach for solving them efficiently and in a mathematically sound man...

Radiation therapy has been one of the major treatment modalities for the prostate cancer over the past few decades. Treatment planning system (TPS) is an integral component in radiation therapy in order to ensure the accurate estimation of radiation dose to the tumor. However, due to the variability in optimization techniques and beam modeling among various TPS, the current literature on radiat...