A review on fetal dose in Radiotherapy: A historical to contemporary perspective

• Published in: Physica medica Vol. 105; p. 102513
• Main Authors: Wong, Yun Ming, Koh, Calvin Wei Yang, Lew, Kah Seng, Chua, Clifford Ghee Ann, Nei, Wenlong, Tan, Hong Qi, Lee, James Cheow Lei, Mazonakis, Michael, Damilakis, John
• Format: Journal Article
• Language: English
• Published: Italy Elsevier Ltd 01.01.2023
• Subjects: Female; Fetal dose; Fetus - radiation effects; Humans; IGRT; Monte Carlo; out-of-field dose; Pregnancy; Pregnancy Complications, Neoplastic - radiotherapy; proton therapy; Proton Therapy - adverse effects; radiotherapy; Radiotherapy Dosage; radiotherapy; proton therapy; out-of-field dose; IGRT; Fetal dose; Monte Carlo
• ISSN: 1120-1797; 1724-191X
• DOI: 10.1016/j.ejmp.2022.102513

•Gy dose threshold for fetal dose to limit adverse effect of radiation.•Estimate fetal dose with Monte Carlo method or phantom measurement before treatment.•Shielding and dose reduction techniques to further reduce out-of-field dose.•Neutrons contribute most to fetal out-of-field dose in proton therapy.•Use of daily CBCT in IGRT for pregnant patient should be carefully considered. This paper aims to review on fetal dose in radiotherapy and extends and updates on a previous work1 to include proton therapy. Out-of-field doses, which are the doses received by regions outside of the treatment field, are unavoidable regardless of the treatment modalities used during radiotherapy. In the case of pregnant patients, fetal dose is a major concern as it has long been recognized that fetuses exposed to radiation have a higher probability of suffering from adverse effects such as anatomical malformations and even fetal death, especially when the 0.1Gy threshold is exceeded. In spite of the low occurrence of cancer during pregnancy, the radiotherapy team should be equipped with the necessary knowledge to deal with fetal dose. This is crucial so as to ensure that the fetus is adequately protected while not compromising the patient treatment outcomes. In this review paper, various aspects of fetal dose will be discussed ranging from biological, clinical to the physics aspects. Other than fetal dose resulting from conventional photon therapy, this paper will also extend the discussion to modern treatment modalities and techniques, namely proton therapy and image-guided radiotherapy, all of which have seen a significant increase in use in current radiotherapy. This review is expected to provide readers with a comprehensive understanding of fetal dose in radiotherapy, and to be fully aware of the steps to be taken in providing radiotherapy for pregnant patients.