The efficient delivery of intensity modulated radiation therapy (IMRT) depends on finding optimized beam intensity patterns that produce dose distributions, which meet given constraints for the tumour as well as any critical organs to be spared. Many optimization algorithms that are used for beamlet-based inverse planning are susceptible to large variations of neighbouring intensities. Accurate...

Cancer is the second leading cause of death behind heart disease in the United States (National Center for Health Statistics, 2006). Various caner treatments are available now, but the three most common types are surgery, chemotherapy, and radiotherapy. Radiotherapy uses radiation—in the form of a special kind of x-rays, γ-rays, electrons, or protons to kill cancer cells. The advance of modern ...

The indications for post-prostatectomy radiotherapy have evolved over the last decade, although the optimal timing, dose, and target volume remain to be well defined. The target volume is susceptible to anatomical variations with its borders interfacing with the rectum and bladder. Image-guided intensity-modulated radiotherapy has become the gold standard for radical prostate radiotherapy. Here...

introduction: breast conserving radiotherapy is one of the most common procedures performed in any radiation oncology department. a tangential parallel-opposed pair is usually used for this purpose. this technique is performed using 2d or 3d treatment planning systems. the aim of this study was to compare 2d treatment planning with 3d treatment planning in tangential irradiation in breast conse...

PURPOSE To propose a method of intensity-modulated radiotherapy (IMRT) planning that generates achievable dose-volume histogram (DVH) objectives using a database containing geometric and dosimetric information of previous patients. METHODS AND MATERIALS The overlap volume histogram (OVH) is used to compare the spatial relationships between the organs at risk and targets of a new patient with ...

We have successfully created a single arc volumetric modulated arc therapy (VMAT) plan for treating post-surgical left breast/chest wall and regional nodes using Elekta multileaf collimator (MLC). Dose volume histograms (DVHs) were compared between the VMAT plans and conventional tangential beam plans using a field-in-field technique, leading to significant DVH advantages in the VMAT plans. The...

Cone-beam computed tomography (CBCT) images are presently used for geometric verification for daily patient positioning. In this work, we have compared the images of CBCT with the images of conventional fan beam CT (FBCT) in terms of image quality and Hounsfield units (HUs). We also compared the dose calculated using CBCT with that of FBCT. Homogenous RW3 plates and Catphan phantom were scanned...

Intensity-modulated radiation therapy (IMRT) can be delivered inefficiently using the movable jaws of a linac. The efficiency can be much improved by delivering IMRT with the movable jaws together with a relocatable mask below the jaws (Webb 2002 Phys. Med. Biol. 47 257-75). This paper extends the modelling work by showing that a much simpler relocatable mask than previously conceptualized can ...