title: A treatment planning strategy for heavy-charged-particle radiotherapy of lung cancer by the use of computed tomography with projection data-based temporal maximum-intensity projection.
abstract: To design a range-compensating bolus for heavy-charged-particle radiotherapy of lung cancer, we propose an image-processing method that uses CT projection data for treatment planning. We studied six lung cancer patients in 4DCT mode. Three types of range-compensating bolus were designed with use of (1) each bolus for 4DCT images, (2) image-based maximum-intensity projection data (4DIM), and (3) CT images reconstructed by the use of maximum-attenuation projection data (4DPM) along the time axis around exhale (=respiratory-gated treatment). Carbon-ion dose distributions were calculated by the use of these designed range-compensating boluses and were compared. The dose distribution with 4DIM caused overdosing beyond the target. However, the dose distribution with 4DPM was similar to that with a composite of the range-compensating bolus (CCB) designed for the respiratory phases. Furthermore, the volume of the receiving dose for >95% (D95) for CTV and the volume of the lung receiving dose for >20 GyE (V20) with 4DPM were similar to that with the CCB. The range-compensating bolus with 4DPM provides dose distributions similar to that with the CCB in peripheral lung cancer and improves the calculating efficiency over CCB.
authors.affiliation: Accelerator Engineering Corporation, Chiba, Chiba, Japan. aec_asa@nirs.go.jp
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Asakura
authors.forename: Motoki
authors.initials: M
authors.lastname: Kumagai
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Kanematsu
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Mori
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D002244:Carbon / Q000627:therapeutic use; D005260:Female; D056973:Four-Dimensional Computed Tomography / Q000379:methods*; D063193:Heavy Ion Radiotherapy; D006801:Humans; D007091:Image Processing, Computer-Assisted; D008175:Lung Neoplasms / Q000000981:diagnostic imaging* / Q000532:radiotherapy*; D008297:Male; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted / Q000379:methods*; D013997:Time Factors
chemical_list: D002244:Carbon
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