Importance of dosimetry protocol for cell irradiation on a low X-rays facility and consequences for the biological response

Abstract

Purpose: The main objective of radiobiology is to establish links between doses and radiation-induced biological effects. In this context, well-defined dosimetry protocols are crucial to the determination of experimental protocols. This work proposes a new dosimetry protocol for cell irradiation in a SARRP and shows the importance of the modification of some parameters defined in dosimetry protocol for physical dose and biological outcomes.

Materials and methods: Once all parameters of the configuration were defined, dosimetry measurements with ionization chambers and EBT3 films were performed to evaluate the dose rate and the attenuation due to the cell culture medium. To evaluate the influence of changes in cell culture volume and/or additional filtration, 6-well plates containing EBT3 films with water were used to determine the impact on the physical dose at 80 kV. Then, experiments with the same irradiation conditions were performed by replacing EBT3 films by HUVECs. The biological response was assessed using clonogenic assay.

Results: Using a 0.15 mm copper filter lead to a variation of +1% using medium thickness of 0.104 cm to −8% using a medium thickness of 0.936 cm on the physical dose compare to the reference condition (0.313 cm). For the 1 mm aluminum filter, a variation of +8 to −40% for the same medium thickness conditions has been observed. Cells irradiated in the same conditions showed significant differences in survival fraction, corroborating the effects of dosimetric changes on physical dose.

Conclusions: This work shows the importance of dosimetry in radiobiology studies and the need of an accurate description of the dosimetry protocol used for irradiation.

KEYWORDS:

• Clonogenic assay
• dosimetry
• HUVECs
• low-energy X-rays
• SARRP

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Morgane Dos Santos is a physics researcher who focus her work on dosimetry and in charge of the SARRP platform at IRSN.

Vincent Paget is a researcher radiobiologist who focus his work on radiobiological effects for several kinds and qualities of ionizing radiation exposure.

Mariam Ben Kacem is a PhD student in the field of radiation biology at IRSN. Ben Kacem focuses on studying biological effects of endothelial cells exposed to radiation of different modalities.

François Trompier is a physics researcher witch focus his work on dosimetry and EPR spectroscopy.

Mohamed Amine Benadjaoud, PhD in Biostatistics and MSc in medical physics, Researcher at the Institute for Radiological Protection and Nuclear Safety (IRSN). His main activities include the development of multiscale risk models through radiobiological data integration.

Agnès François is a researcher radiobiologist with an expertise in the field of radiation-induced normal tissue damages.

Olivier Guipaud is a researcher in the field of radiobiology of the vascular endothelium at IRSN. Guipaud focuses on endothelial factors involved in the recruitment of immune cells into tumours and normal tissues following radiotherapy.

Marc Benderitter is a radiopathologist and the head of the Department of RAdiobiology and regenerative MEDicine (SERAMED) at IRSN.

Fabien Milliat is a researcher and the head of the Laboratory of Medical Radiobiology at IRSN. Milliat is an expert in the field of radiobiological effects and on the role of the vascular compartment in radiation-induced normal tissue damages.

Additional information

Funding

This work was supported by Electricité de France EDF (Groupe Gestion Projet Radioprotection) and the Institute for Radiological Protection and Nuclear Safety (ROSIRIS program).