The cervix case showed that also in IMRT with coplanar setups, beam angle optimization with iCycle may improve plan quality. For the maxillary sinus and liver cases, significant improvements for noncoplanar setups were seen.
Plans generated with beam angle optimization did better meet the clinical goals than equiangular or manually selected configurations. Performance and characteristics of iCycle are demonstrated by generating plans for a maxillary sinus case, a cervical cancer patient, and a liver patient treated with SBRT. Plan generation with iCycle is fully automated. Pareto-optimal plan is generated until addition of beams does no longer result in significant plan quality improvement. For each patient, a single one-beam, two-beam, three-beam, etc. To select the next direction, each not yet selected candidate direction is temporarily added to the plan and an optimization problem, derived from the Lagrangian obtained from the just performed optimization for establishing the Pareto-optimal plan, is solved. Then, a Pareto-optimal IMRT plan is generated for the (fixed) beam setup that includes all so far selected directions, using a previously published algorithm for multicriterial optimization of fluence profiles for a fixed beam arrangement Breedveld et al.
Each iteration loop starts with selection of the optimal direction to be added. This could be realized by sequentially adding beams to the treatment plan in an iterative procedure. Obtaining clinically feasible calculation times was an important design criterium for development of iCycle. Input sets can be restricted, e.g., to allow only generation of coplanar plans, or to avoid collisions between patient/couch and the gantry in a noncoplanar setup. Beam directions are selected from an input set of candidate directions. The higher an objective priority is, the higher the probability that the corresponding objective will be met. Priorities are ordinal parameters used for relative importance ranking of the objectives. How? Through movement.To introduce iCycle, a novel algorithm for integrated, multicriterial optimization of beam angles, and intensity modulated radiotherapy (IMRT) profiles.Ī multicriterial plan optimization with iCycle is based on a prescription called wish-list, containing hard constraints and objectives with ascribed priorities. There’s never been a better time to reconnect with your body and mind for a better night’s sleep.
Lina Törnquist Born to move – sleep better by moving like you’ve never moved before But spending too much time indoors may be disrupting it. The sleep-wake cycle is regulated by the body’s internal 24-hour clock – the circadian rhythm. A day in the life of Sleep Cycle’s Sleep Expert, Li ÅslundĮver wondered what sleep advice a sleep expert would give…Īnju Khanna Saggi How to use light to reboot your circadian rhythm
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