Experimental validation of a 4D dose calculation routine for pencil beam scanning proton therapy

4D robust optimization including uncertainties in time structures can reduce the interplay effect in proton pencil beam scanning radiation therapy

“…On the delivery machine side, it is highly desirable that the time structure is stable, so that any uncertainties related to the delivery machine could be neglected. For this sake, it is of importance to have a realistic delivery simulation of the machine reflecting the actual delivery, for example, from the ScanAlgo simulation tool or from experimentally determined time structures . If an interlock occurs in the machine, the delivery should be resumed in the same position in the breathing cycle to ensure that robustness is maintained.…”

“…The interplay effect is evaluated in a separate framework from the robust optimization, but based on the same principles using a 4D dose calculation. It is implemented in the scripting environment of RayStation 7 and has been experimentally verified by Pfeiler et al 42 The method distributes the spots over the different breathing cycle phases, computes the partial beam doses, and maps the doses back to a reference phase utilizing deformable registrations. The organ motion is described by the phases in the 4DCT and by different realistic breathing signals in each evaluation scenario.…”

A Monte‐Carlo‐based and GPU‐accelerated 4D‐dose calculator for a pencil beam scanning proton therapy system

“…Experimental validation of any 4DDC will increase confidence in its use (see, e.g., Refs. and ) and studies for such validation of the presented 4DDC are underway.…”

“…Faced with the complexities of 4D treatment, standard dose‐calculation engines found in treatment planning systems (TPSs) that only consider dose to a static three‐dimensional (3D) geometry are insufficient to fully describe the expected dose distribution for cases with tumor/organ motion; a 4D‐dose calculator (4DDC) is thus necessary . Although some TPSs offer methods to compute 4D dose, these offerings are nonideal for several reasons.…”

Log file‐based dose reconstruction and accumulation for 4D adaptive pencil beam scanned proton therapy in a clinical treatment planning system: Implementation and proof‐of‐concept

“…the utility of this in‐house deforming grid 4D dose calculation for the evaluation of different PBS techniques in terms of effectiveness and efficiency of rescanning moving targets was demonstrated. A 4D dose calculation routine for PBS proton therapy using machine log files and motion pattern was also recently implemented in RayStation by Pfeiler et al . In a simple phantom setup, it was shown that this implementation could be used to evaluate interplay effects.…”