title: Comparison of IMRT treatment plans between linac and helical tomotherapy based on integral dose and inhomogeneity index.
abstract: Intensity modulated radiotherapy (IMRT) is an advanced treatment technology for radiation therapy. There are several treatment planning systems (TPS) that can generate IMRT plans. These plans may show different inhomogeneity indices to the planning target volume (PTV) and integral dose to organs at risk (OAR). In this study, we compared clinical cases covering different anatomical treatment sites, including head and neck, brain, lung, prostate, pelvis, and cranio-spinal axis. Two treatment plans were developed for each case using Pinnacle(3) and helical tomotherapy (HT) TPS. The inhomogeneity index of the PTV and the non-tumor integral dose (NTID) were calculated and compared for each case. Despite the difference in the number of effective beams, in several cases, NTID did not increase from HT as compared to the step-and-shoot delivery method. Six helical tomotherapy treatment plans for different treatment sites have been analyzed and compared against corresponding step-and-shoot plans generated with the Pinnacle(3) planning system. Results show that HT may produce plans with smaller integral doses to healthy organs, and fairly homogeneous doses to the target as compared to linac-based step-and-shoot IMRT planning in special treatment site such as cranio-spinal.
authors.affiliation: Cancer Therapy and Research Center, San Antonio, TX 78229, USA. shic@uthscsa.edu
authors.forename: Chengyu
authors.initials: C
authors.lastname: Shi
authors.forename: Jose
authors.initials: J
authors.lastname: Peñagarícano
authors.forename: Niko
authors.initials: N
authors.lastname: Papanikolaou
mesh_terms: D000293:Adolescent; D000368:Aged; D001822:Body Burden; D001932:Brain Neoplasms / Q000532:radiotherapy; D020000:Decision Support Systems, Clinical; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006258:Head and Neck Neoplasms / Q000532:radiotherapy; D006801:Humans; D008175:Lung Neoplasms / Q000532:radiotherapy; D008297:Male; D008875:Middle Aged; D010386:Pelvic Neoplasms / Q000532:radiotherapy; D011471:Prostatic Neoplasms / Q000532:radiotherapy; D011836:Radiation Tolerance; D011873:Radiology Information Systems; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D050397:Radiotherapy, Intensity-Modulated / Q000379:methods*; D012062:Relative Biological Effectiveness; D013125:Spinal Neoplasms / Q000532:radiotherapy; D036542:Tomography, Spiral Computed; D014894:Weights and Measures