Radioprotection 2025, 60( 1), 50 – 56 © A. Chaikh et al., Published by EDP Sciences, 2025 https:// doi. org / 10.1051 / radiopro / 2024039
Available online at: www. radioprotection. org
ARTICLE Modeling and dosimetric characterization of a 3D printed pregnant woman phantom for fetal dosimetry in radiotherapy
A. Chaikh 1,*, A. Chaabane 1, C. Jardin 2, S. Bassot 3, T. Beaumont 4, M. Chea 5, M. Khalal 5, C. Jenny 5, S. Thomas 6, C. Huet 7, A. Isambert 1 and M. Edouard 1
1 IRSN, PSE-SANTE / SER / UEM, 92260 Fontenay-aux-Roses, France. 2 IRSN, PSE-ENV / SPDR / LT2S, 92260 Fontenay-aux-Roses, France. 3 IRSN, PSE-ENV / SPDR, 92260 Fontenay-aux-Roses, France. 4 IRSN, PSE-SANTE / SDOS / LEDI, 92260 Fontenay-aux-Roses, France. 5 Medical Physics Department, Pitié-Salpêtrière Hospital, AP-HP Sorbonne University, France. 6 IRSN, PSE-SANTE / SER / BERIN, 92260 Fontenay-aux-Roses, France. 7 IRSN, PSE-SANTE / SDOS / LDRI, 92260 Fontenay-aux-Roses, France.
Received: 10 June 2024 / Accepted: 19 August 2024
Abstract – A phantom-based estimation of the fetal dose for pregnant women undergoing radiotherapy and its optimization are recommended by the French society for radiation oncology. The objective of this study was to model and print 3D bellies representing various stages of pregnancy, that could be added to a female ATOM ® phantom, enabling fetal dose assessment through measurements for optimization studies. The bellies were designed based on fundal height values from gynecological references and printed using a Stratasys 3D Printer and VeroWhite resin. Its chemical composition was determined using a CHONS analyzer: 65.51 % carbon( C), 7.95 % hydrogen( H), 23.3 % oxygen( O), and 2.89 % nitrogen( N). Its physical density was assessed using the helium pycnometry method: 1.190 þ / �0.001. The linear attenuation coefficients for VeroWhite resin were evaluated using two methods: by calculations based on the linear attenuation coefficients of each chemical element and by experimental attenuation measurements using a 6 MV beam. Consistent results were obtained with both methods; the VeroWhite resin is approximately 15 % higher attenuation than water according to the calculation method and approximately 12 % higher attenuation than RW3 water equivalent plates with the experimental method. These results were considered as acceptable for comparative parametric studies of fetal dose.
Keywords: radiotherapy / pregnant woman / VeroWhite / 3D Printer
1 Introduction
While IRSN has extensive experience with fetal exposure during radiological or nuclear medicine examinations( Étard and Aubert, 2009), fetal radiation protection during radiotherapy of pregnant women remains rare and understudied. Fetal dose assessment for pregnant women undergoing radiotherapy is challenging due to several factors. Firstly, the fetus is located outside the treated volume, where treatment planning systems cannot accurately calculate the dose. Secondly, currently commercially available phantoms do not simulate pregnant women. For radiotherapy, healthcare professionals are faced with situations where they must find a balance between improving the patient’ s survival and quality of life while ensuring radiation protection for the fetus. The French society
* Corresponding author: abdulhamid. chaikh @ irsn. fr for radiation oncology updated its recommendations on radiotherapy and pregnancy in 2022( Michalet et al., 2022). They particularly recommend a phantom-based estimation of the dose delivered to the fetus and its optimization. To our knowledge, there is no commercially available phantom that allows the evaluation of fetal dose for radiotherapy. However, a phantom as close as possible to the anatomy of a pregnant patient is preferable. Indeed, the use of a female human phantom or an equivalent phantom, without any additional tissue material over the phantom’ s abdomen to simulate pregnancy, may introduce unknown inaccuracies in the fetal dose estimation( Mazonakis and Damilakis, 2017). An accurate estimation of fetal dose is necessary to evaluate the risks of radiation exposure for the fetus( ICRP No. 84, 2000)( Streffer et al., 2003) and enables the optimization of fetal dose by comparing, for example, the impact on this dose of different treatment parameters( i. e., beam configuration, energy, etc) or treatment modalities( Noël et al., 2006). According to the
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