Radiation Dose to the Fetus From Computed Tomography of Pregnant Patients—Development and Validation of a Web-Based Tool

Abstract

OBJECTIVE Estimations of radiation dose absorbed by the fetus from computed tomography (CT) in pregnant patients is mandatory, but currently available methods are not feasible in clinical routine. The aims of this study were to develop and validate a tool for assessment of fetal dose from CT of pregnant patients and to develop a user-friendly web interface for fast fetal dose calculations. METHODS In the first study part, 750 Monte Carlo (MC) simulations were performed on phantoms representing pregnant patients at various gestational stages. The MC code simulating vendor-independent dose distributions was validated against CT dose index (CTDI) measurements performed on CT scanners of 2 vendors. The volume CTDI-normalized fetal dose values from MC simulations were used for developing the computational algorithm enabling fetal dose assessments from CT of various body regions at different exposure settings. In the institutional review board-approved second part, the algorithm was validated against patient-specific MC simulations performed on CT data of 29 pregnant patients (gestational ages 8-35 weeks) who underwent CT. Furthermore, the tool was compared with a commercially available software. A user-friendly web-based interface for fetal dose calculations was created. RESULTS Weighted CTDI values obtained from MC simulations were in excellent agreement with measurements performed on the 2 CT systems (average error, 4%). The median fetal dose from abdominal CT in pregnant patients was 2.7 mGy, showing moderate correlation with maternal perimeter (r = 0.69). The algorithm provided accurate estimates of fetal doses (average error, 11%), being more accurate than the commercially available tool. The web-based interface (www.fetaldose.org) enabling vendor-independent calculations of fetal doses from CT requires the input of gestational age, volume CTDI, tube voltage, and scan region. CON-CLUSIONS A tool for fetal dose assessments from CT of pregnant patients was developed and validated being freely available on a user-friendly web interface.

Effects of ionizing radiation exposure during pregnancy

“…A recent publication [ 57 ] demonstrated a validated non-commercial web-based tool for fast conceptus dose calculations after CT scan ( www.fetaldose.org ) which requires data input of 4 parameters including trimester number, kV, scan range and radiation output parameter of CTDI vol . Note, we recommend use of software tools with caution as, without fully understanding the assumptions used, these can result in incorrect dose estimation and impact patient care.…”

Proton therapy of a pregnant patient with nasopharyngeal carcinoma

“…Plan adaptations were not required. The weekly repeat and planning CTs accounted for an additional fetal radiation dose of 0.21 mSv, with no abdominal shielding being used [14] . Accounting for both treatment and imaging, the total fetal radiation dose was 5.8 mSv.…”

Diagnosis and Treatment of Renal Cell Carcinoma During Pregnancy

“… 7 For pregnant patients who must undergo these imaging examinations, the radiation dose should be <0.1 Gy, and the examination should be conducted with the abdomen shielded to ensure the fetus is safe. 8 CT and magnetic resonance imaging (MRI) are the preferred imaging examinations for diagnosing RCC. Clinically the safest imaging examinations during pregnancy are ultrasonography and MRI.…”