title: Estimation of the secondary cancer risk induced by diagnostic imaging radiation during proton therapy.
abstract: We have estimated the secondary cancer risk (SCR) introduced by image-guided procedures during proton therapy. The physical dose from imaging radiation and the corresponding organ equivalent dose were calculated for the case of a lumbar spine patient. The maximum physical dose delivered to the patient during the imaging procedure was estimated to be ~0.35% of the prescribed dose of 46 Gy. However, this small imaging dose substantially raised the radiation-induced SCR by ~8%. In addition, the clinical benefit (improved accuracy during the procedure) and costs (extra SCR) associated with image-guided procedures were quantitatively modelled by systematically investigating the changes in SCR as a function of the prescribed dose, treatment target volume and imaging field size. The results showed that the SCR varied sensitively with the volume receiving the imaging and the therapeutic radiation, whereas the SCR depended to a lesser extent on the magnitude of the applied therapeutic radiation. These results showed that the additional SCR introduced by imaging radiation could be efficiently reduced by minimizing the imaging field size during image-guided procedures.
authors.affiliation: Proton Therapy Center, National Cancer Center, Goyang, Republic of Korea.
authors.forename: Hojin
authors.initials: H
authors.lastname: Jeong
authors.forename: Jeong-Eun
authors.initials: JE
authors.lastname: Rah
authors.forename: Ui-Jung
authors.initials: UJ
authors.lastname: Hwang
authors.forename: Seung Hoon
authors.initials: SH
authors.lastname: Yoo
authors.forename: Byung Jun
authors.initials: BJ
authors.lastname: Min
authors.forename: Sang-Yeob
authors.initials: SY
authors.lastname: Lee
authors.forename: Myonggeun
authors.initials: M
authors.lastname: Yoon
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Shin
authors.forename: Sung Yong
authors.initials: SY
authors.lastname: Park
authors.forename: Se Byeong
authors.initials: SB
authors.lastname: Lee
authors.forename: Joo-Young
authors.initials: JY
authors.lastname: Kim
mesh_terms: D003198:Computer Simulation; D003952:Diagnostic Imaging / Q000009:adverse effects*; D005260:Female; D006801:Humans; D008954:Models, Biological; D009381:Neoplasms, Radiation-Induced / Q000209:etiology*; D061766:Proton Therapy; D011522:Protons / Q000009:adverse effects; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D061089:Radiotherapy, Image-Guided / Q000009:adverse effects*; D018570:Risk Assessment
chemical_list: D011522:Protons