PURPOSE: The development of automated "inverse planning," utilizing intensity-modulated radiation therapy (IMRT) raises the question of whether this new technique can provide a practical and efficient means of dose escalation in conformal treatment of @entity263 . The purpose of this feasibility study was to determine a single set of inverse-planning parameters that can be used for a variety of different prostate @entity1 geometries to automatically generate escalated dose (> or = 81 Gy) IMRT plans that satisfy normal tissue constraints for rectal and bladder walls. METHODS: We studied a subset of the 46 @entity1 who were previously treated at Memorial Sloan Kettering Cancer Center (MSKCC) to a total dose of 81 Gy using a 3D conformal approach. Six @entity1 were selected for our study and replanned using an analytical inverse-planning algorithm (referred to as OPT3D) applied to 8 intensity modulated, co-axial radiation beams. A set of more than a dozen inverse planning parameters were adjusted by trial and error until the resulting dose distributions satisfied the critical organ dose-volume constraints imposed by our study rules (D30 < or = 75.6 Gy and D10 < or = 80 Gy for the rectal wall; D15 < or = 80 Gy for the bladder wall) for the sample of @entity1 selected. The OPT3D-generated plans were compared to hand-generated @entity1493 plans using cumulative DVH analysis. RESULTS: A single set of inverse-planning parameters was found that was able to automatically generate IMRT plans meeting all critical organ dose-volume constraints for all but one of the @entity1 in our study. [The exception failed to meet bladder dose constraints for both IMRT and @entity1493 methods, due to extensive overlap between the planning target volume ( @entity343 ) and bladder contours]. Based upon analysis of the cumulative dose-volume histogram (DVH) for the prostate @entity343 , the D95 (DX is defined such that x% of the volume receives a dose > or = DX), averaged over all @entity1 , was approximately 81 Gy. The average D90 and mean dose values were 85 Gy and 93 Gy, respectively. Although a similar D95 was achieved using the @entity1493 -generated plans, the D90 and mean dose values were substantially higher for the inverse planning (OPT3D) method. CONCLUSION: This limited "paper study" shows IMRT with inverse planning to be a promising technique for the treatment of @entity263 to high doses. We determined a small set of inverse-planning parameter values that was able to automatically design intensity-modulated radiotherapy (IMRT) plans for a subset of 6 @entity1 previously treated at MSKCC to 81 Gy using @entity1493 planning techniques. With one minor exception, the resulting plans succeeded in meeting predetermined dose-volume constraints while at the same time allowing an increase in the mean dose and D90 to the prostate @entity343 . These 8 field plans also resulted in reduced dosage to the femoral heads. This automated technique is efficient in terms of planning effort and, with proper software for computer-controlled MLC, may be appropriate for clinical use. The clinical feasibility of this approach for a larger group of @entity1 is currently under study.

A feasibility study of automated inverse treatment planning for XXXX .

@entity1 :: ('9606', 'Species') :: ['patients', 'patient'] @entity263 :: ('MESH:D011471', 'Disease') :: ['prostate cancer', 'cancer of the prostate'] @entity343 :: ('187978', 'Species') :: ['PTV'] @entity1493 :: ('12064', 'Species') :: ['BEV']
@entity263 :: (MESH:D011471,Disease) :: ['cancer of the prostate']
