Grid therapy using high definition multileaf collimators: realizing benefits of the bystander effect

Mini and Micro Multileaf Collimators

Multiple arc or multiple field convergent beam irradiation techniques have been used extensively for stereotactic radiosurgery (SRS) or radiotherapy (SRT) of small lesions. A major problem is that dose distributions produced by employing rectangular or circular collimators are of simple convex shape and therefore do not allow conformal treatment of irregularly shaped lesions. The use of multipl...

Algorithms for Sequencing Multileaf Collimators

Realization of Intensity Modulated Radiation Fields Using Multileaf Collimators

In the treatment of cancer using high energetic radiation the problem arises how to irradiate the tumor without damaging the healthy tissue in the immediate vicinity. In order to do this as efficiently as possible intensity modulated radiation therapy (IMRT) is used. A modern way to modulate the homogeneous radiation field delivered by an external accelerator is to use a multileaf collimator in...

Optimal Sequencing of Dynamic Multileaf Collimators

Dynamic multileaf collimator (DMLC)-intensity modulated radiation therapy (IMRT) is used to delivery intensity-modulated beams using an MLC, with the leaves in motion. DMLC-IMRT requires the conversion of a radiation fluence map into a leaf sequence file that controls the movement of the MLC while the beam is on. It is imperative that the fluence map delivered using the leaf sequence file be as...

the effect of using model essays on the develpment of writing proficiency of iranina pre-intermediate efl learners

abstract the present study was conducted to investigate the effect of using model essays on the development of writing proficiency of iranian pre-intermediate efl learners. to fulfill the purpose of the study, 55 pre- intermediate learners of parsa language institute were chosen by means of administering proficiency test. based on the results of the pretest, two matched groups, one as the expe...