TY - JOUR
T1 - A validation study of a dedicated software for an automated in vivo dosimetry control in radiotherapy
AU - Piermattei, Angelo
AU - Greco, F.
AU - Grusio, M.
AU - Menna, S.
AU - Azario, Luigi
AU - Stimato, Gerardina
AU - Placidi, Elisa
AU - Teodoli, S.
AU - Cilla, S.
AU - Cilla, Savino
AU - Porcelli, A.
AU - Alberico, Lorenzo
AU - Fidanzio, Andrea
PY - 2018
Y1 - 2018
N2 - In vivo dosimetry (IVD) is the last step of a radiotherapy quality control program aimed to ensure that the dose delivered is in agreement with that prescribed. IVD procedures based on single detectors are time-consuming and impossible to use for the modern radiotherapy techniques, based on static or kinetic beams (modulated in intensity fluence); this means that more efficient and practical methods are highly recommended. The practical method SOFTDISO, based on the use of electronic portal image device (EPID), provides two tests (i) the R ratio between the reconstructed and the planned isocenter doses to verify an agreement within 5% and (ii) the γ-analysis of the EPID images, to verify γ% ≥ 90% and γmean ≤ 0.4. This paper reports the results of 11,357 IVD tests carried out for 823 patients treated by three-dimensional conformal radiation therapy and volumetric modulated arc therapy techniques. In particular, the dose disagreements are reported distinguishing two kinds of causes, those of (i) class 1 that includes the errors due to inadequate quality controls and (ii) the class 2, due to patient morphological changes. About the tests out of tolerance, 6% were by VMAT and 21% by 3DCRT, but taking into account the only class 1 of errors, i.e., removing the causes of class 2, only 7% of patients examined presented at least one of the three mean indexes out of tolerance. The workload for IVD on 9 patients/day per linac is about 52 min/day but recently, a new automated SOFTDISO version has been implemented to reduce the time to about 34 min/day.
AB - In vivo dosimetry (IVD) is the last step of a radiotherapy quality control program aimed to ensure that the dose delivered is in agreement with that prescribed. IVD procedures based on single detectors are time-consuming and impossible to use for the modern radiotherapy techniques, based on static or kinetic beams (modulated in intensity fluence); this means that more efficient and practical methods are highly recommended. The practical method SOFTDISO, based on the use of electronic portal image device (EPID), provides two tests (i) the R ratio between the reconstructed and the planned isocenter doses to verify an agreement within 5% and (ii) the γ-analysis of the EPID images, to verify γ% ≥ 90% and γmean ≤ 0.4. This paper reports the results of 11,357 IVD tests carried out for 823 patients treated by three-dimensional conformal radiation therapy and volumetric modulated arc therapy techniques. In particular, the dose disagreements are reported distinguishing two kinds of causes, those of (i) class 1 that includes the errors due to inadequate quality controls and (ii) the class 2, due to patient morphological changes. About the tests out of tolerance, 6% were by VMAT and 21% by 3DCRT, but taking into account the only class 1 of errors, i.e., removing the causes of class 2, only 7% of patients examined presented at least one of the three mean indexes out of tolerance. The workload for IVD on 9 patients/day per linac is about 52 min/day but recently, a new automated SOFTDISO version has been implemented to reduce the time to about 34 min/day.
KW - Anatomic Landmarks
KW - Automation
KW - Dosimetry
KW - Humans
KW - In Vivo Dosimetry
KW - Quality controls in radiotherapy
KW - Radiotherapy Dosage
KW - Radiotherapy in vivo dosimetry
KW - Radiotherapy, Conformal
KW - Radiotherapy, Intensity-Modulated
KW - Reproducibility of Results
KW - Software
KW - Anatomic Landmarks
KW - Automation
KW - Dosimetry
KW - Humans
KW - In Vivo Dosimetry
KW - Quality controls in radiotherapy
KW - Radiotherapy Dosage
KW - Radiotherapy in vivo dosimetry
KW - Radiotherapy, Conformal
KW - Radiotherapy, Intensity-Modulated
KW - Reproducibility of Results
KW - Software
UR - http://hdl.handle.net/10807/172187
U2 - 10.1007/s11517-018-1822-3
DO - 10.1007/s11517-018-1822-3
M3 - Article
SN - 0140-0118
VL - 56
SP - 1939
EP - 1947
JO - MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING
JF - MEDICAL & BIOLOGICAL ENGINEERING & COMPUTING
ER -