文档介绍：Radiotherapy and Oncology 89 (2008) 180–191
Cervix cancer radiotherapy
A treatment planning paring volumetric arc
modulation with RapidArc and fixed field IMRT for
cervix uteri radiotherapy
Luca Cozzia,b,*, Ketayun Ardeshir Dinshawc, Shyam Kishore Shrivastavac,
Umesh Mahantshettyc, Reena Engineerc, Deepak Dattatray Deshpandec, . Jamemac,
Eugenio tia, Alessandro Clivioa, ia Nicolinia, Antonella Fogliataa
aOncology Institute of Southern Switzerland, Medical Physics Unit, Bellinzona, Switzerland, bUniversity of Lausanne, Faculty of
Medicine, Lausanne, Switzerland, cDepartment of Radiation Oncology & Medical Physics, Tata Memorial Hospital, Mumbai, India
Abstract
Purpose: A treatment planning study was performed to evaluate the performance of the novel volumetric modulated
single arc radiotherapy on cervix uteri cancer patients. Conventional fixed field IMRT was used as benchmark.
Methods and materials: CT datasets of eight patients were included in the study. Plans were optimised with the aim to
ans at risk and healthy tissue sparing while enforcing highly conformal target coverage. Planning objectives for
PTV were: maximum significant dose lower than Gy and minimum significant dose higher than Gy. ans at
risk, the median and maximum doses were constrained to be lower than 30 (rectum), 35 (bladder) and 25 Gy (small
bowel) and Gy; additional objectives were set on various volume thresholds. Plans were evaluated on parameters
derived from dose volume histograms and on NTCP estimates. Peripheral doses at 5, 10 and 15 cm from the PTV surface
were recorded to assess the low-level dose bath. The MU and delivery time were scored to measure expected treatment
efficiency.
Results: Both RapidArc and IMRT resulted in equivalent target coverage but RapidArc had an improved homogeneity
(D5%–D95% = ± Gy for RapidArc and ± Gy for IMRT) and conformity index (CI90% = ± for RapidArc
and ± for IMRT). On re