PURPOSE: Conformal treatment planning with megavoltage x-rays and protons for five @entity1 with @entity418 has been studied in an attempt to determine if there are advantages of using protons instead of x-rays. METHODS AND MATERIALS: For each of the five @entity1 , two different proton plans, one x-ray plan, and one mixed plan with x-rays and protons were made. A three-dimensional treatment planning system, TMS, was used. The evaluation of the different plans was made by applying the @entity5 ( @entity5 ) model proposed by Nahum and Webb and the normal tissue complication (NTCP) model proposed by Lyman on the dose distributions in terms of dose-volume histograms (DVHs). RESULTS: The comparison shows advantages of using protons instead of x-rays for all five @entity1 . The dose-limiting organs at risk are the spinal cord, the lungs, and the heart, but the proton plans also spare the kidneys better than the x-ray plan does. At 5% NTCP in any risk organ, the calculated mean @entity5 value for the five @entity1 is increased by an average of 20%-units (from 2 to 23%-units) with the best proton plan compared with x-rays only. However, if we assume maximally a 1% risk in the spinal cord and a total NTCP for the two lungs of 100%, the mean @entity5 value for the five @entity1 is increased from 6 to 49% with the best proton plan compared with x-rays only. The corresponding figure for the mixed plan is 27%. These gains are relatively insensitive to variations within reasonable limits in the biological parameters. CONCLUSIONS: Protons appear to have clear therapeutic advantages over conventional external radiotherapy when treating @entity418 .

Comparative treatment planning between proton and x-ray therapy in XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor control probability', 'TCP'] @entity418 :: ('MESH:D004938', 'Disease') :: ['esophageal cancer', 'esophageal carcinoma']
@entity418 :: (MESH:D004938,Disease) :: ['esophageal cancer']
