Doses delivered by portal imaging quality assurance in routine practice of adjuvant breast radiotherapy worth to by monitored and compensated in some cases - Normandie Université Access content directly
Journal Articles Quantitative Imaging in Medicine and Surgery Year : 2021

Doses delivered by portal imaging quality assurance in routine practice of adjuvant breast radiotherapy worth to by monitored and compensated in some cases

Sami Kefs
  • Function : Author
Jean-Yves Giraud
  • Function : Author
Julie Naud
  • Function : Author
Isabelle Henry
  • Function : Author
Isabelle Gabelle-Flandin
  • Function : Author
Jacques Balosso
  • Function : Author
Camille Verry
  • Function : Author

Abstract

Background: Imaging, in radiotherapy, has become a routine tool for repositioning of the target volume at each session. The repositioning precision, currently infracentimetric, evolves along with the irradiation techniques. This retrospective study aimed to identify practices and doses resulting from the use of high energy planar imaging (portal imaging) in daily practice. Methods: A retrospective survey of portal images (PIs) was carried out over 10 years for 2,403 patients and for three linacs (1 Elekta SLi, 2 Varian Clinac) for postoperative mammary irradiations. Images were taken using a standardized number of monitor units (MU) for all patients. Due to the variable sensitivities of the detectors and the possibility of adjustment of the detector-patient distance, the number of MU were 3; 2 and 1 respectively, for Elekta SLi ® , Clinac 600 ® and Clinac 2100 ®. Then, a representative cumulated dose was calculated in simplified reference conditions (5 cm depth, beam of 10 cm × 10 cm, 6 MV), considering the total number of images taken during the whole treatment course. The consistency between the representative doses and the actual absorbed doses received by the patients was verified by simulating a series of typical cases with the treatment plan dose calculation system. Results: The delivered doses differ significantly between the three linacs. The mean representative dose values by complete treatment were 0.695; 0.241 and 0.216 Gy, respectively, for SLi, Clinac 600 and Clinac 2100. However, 15 patients were exposed to a dose >2 Gy with a maximum dose of 5.05 Gy. The simulated doses were very similar to the representative doses. Conclusions: A significant dose delivery was highlighted by this study. These representative doses are presently communicated weekly to the radiation oncologist for the radiation protection of their patients. Moreover, they should be taken into account in a possible study of long-term stochastic risks.
Fichier principal
Vignette du fichier
69137-PB2-5553-R2.pdf (1.12 Mo) Télécharger le fichier
Origin Publisher files allowed on an open archive
Licence

Dates and versions

hal-03980839 , version 1 (09-02-2023)

Licence

Identifiers

Cite

Sami Kefs, Jean-Yves Giraud, Julie Naud, Isabelle Henry, Isabelle Gabelle-Flandin, et al.. Doses delivered by portal imaging quality assurance in routine practice of adjuvant breast radiotherapy worth to by monitored and compensated in some cases. Quantitative Imaging in Medicine and Surgery, 2021, 11 (8), pp.3481 - 3493. ⟨10.21037/qims-19-1031⟩. ⟨hal-03980839⟩
7 View
23 Download

Altmetric

Share

Gmail Mastodon Facebook X LinkedIn More