Highlights
- •A breast shielding has been designed for interstitial HDR 192Ir brachytherapy.
- •Fetal dose has been evaluated with and without shielding.
- •The shielding reduces absorbed dose by more than a factor of ten beyond 20 cm.
- •The fetus receives less dose with shielded HDR 192Ir BT than with EBRT.
- •Shielded 192Ir BT may benefit pregnant patients needing localized radiotherapy.
Abstract
Purpose
To assess the radiation dose to the fetus of a pregnant patient undergoing high-dose-rate
(HDR) 192Ir interstitial breast brachytherapy, and to design a new patient setup and lead shielding
technique that minimizes the fetal dose.
Methods
Radiochromic films were placed between the slices of an anthropomorphic phantom modeling
the patient. The pregnant woman was seated in a chair with the breast over a table
and inside a leaded box. Dose variation as a function of distance from the implant
volume as well as dose homogeneity within a representative slice of the fetal position
was evaluated without and with shielding.
Results
With shielding, the peripheral dose after a complete treatment ranged from 50 cGy
at 5 cm from the caudal edge of the breast to <0.1 cGy at 30 cm. The shielding reduces
absorbed dose by a factor of two near the breast and more than an order of magnitude
beyond 20 cm. The dose is heterogeneous within a given axial plane, with variations
from the central region within 50%. Interstitial HDR 192Ir brachytherapy with breast shielding can be more advantageous than external-beam
radiotherapy (EBRT) from a radiation protection point of view, as long as the distance
to the uterine fundus is higher than about 10 cm. Furthermore, the weight of the shielding
here proposed is notably lower than that needed in EBRT.
Conclusions
Shielded breast brachytherapy may benefit pregnant patients needing localized radiotherapy,
especially during the early gestational ages when the fetus is more sensitive to ionizing
radiation.
Keywords
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References
American Society of Clinical Oncology – ASCO. Available online: http://www.cancer.net/coping-and-emotions/sexual-and-reproductive-health/cancer-during-pregnancy; [accessed 14.01.15].
- Evaluation of fetal dose in breast radiotherapy with shielding and wedges.IEEE Trans Nucl Sci. 2013; 60: 792-796
- Fetal dose from radiotherapy with photon beams: report of AAPM radiation therapy committee task group no. 36.Med Phys. 1995; 22: 63-82
- Pregnancy and medical radiation.(Annals ICRP, Publication 84. Ottawa, Canada)2000
- Fetal dose during radiotherapy: clinical implementation and review of the literature.Cancer Radiother. 2002; 6: 352-357
- Preconception and prenatal radiation exposure: health effects and protective guidelines.(NCRP Report No. 174. NCRP. Bethesda, MD)2013
- Radiotherapy during pregnancy: fact and fiction.Lancet Oncol. 2005; 6: 328-333
- Current knowledge on tumour induction by computed tomography should be carefully used.Eur Radiol. 2014; 24: 649-656
- Fetal dose evaluation during breast cancer radiotherapy.Int J Radiat Oncol Biol Phys. 1998; 40: 995-999
- Radiotherapy of Hodgkin's disease in early pregnancy: embryo dose measurements.Radiother Oncol. 2003; 66: 333-339
- Technical management of a pregnant patient undergoing radiation therapy to the head and neck.Med Dosim. 1999; 24: 121-128
- Radiotherapy for glioma during pregnancy: fetal dose estimates, risk assessment and clinical management.Clin Oncol. 2004; 16: 210-214
- IMRT in a pregnant patient: how to reduce the fetal dose?.Med Dosim. 2009; 34: 301-310
- Foetal radiation dose in radiotherapy for breast cancer.Australas Radiol. 1992; 36: 321-322
- Measurement of the peripheral dose for the tangential breast treatment technique with Co-60 gamma radiation and high energy x-rays.Radiother Oncol. 1997; 42: 257-264
- Pregnancy and radiation.Cancer Treat Rev. 2001; 27: 1-7
- Evaluation of the peripheral dose to uterus in breast carcinoma radiotherapy.Radiat Prot Dosim. 2002; 101: 469-471
- Measurement and calculation of the dose at large distances from brachytherapy sources: Cs-137, Ir-192, and Co-60.Med Phys. 1996; 23: 537-543
- Accelerated partial breast irradiation consensus statement from the American Society for Radiation Oncology (ASTRO).Int J Radiat Oncol Biol Phys. 2009; 74: 987-1001
- Patient selection for accelerated partial-breast irradiation (APBI) after breast-conserving surgery: recommendations of the Groupe Europeen de Curietherapie-European Society for Therapeutic Radiology and Oncology (GEC-ESTRO) breast cancer working group based on clinical evidence.Radiother Oncol. 2010; 94: 264-273
- The American Brachytherapy Society consensus statement for accelerated partial breast irradiation.Brachytherapy. 2013; 12: 267-277
- A dosimetric comparison of accelerated partial breast irradiation techniques: multicatheter interstitial brachytherapy, three-dimensional conformal radiotherapy, and supine versus prone helical tomotherapy.Int J Radiat Oncol Biol Phys. 2007; 68: 935-942
- Calculated organ doses using Monte Carlo simulations in a reference male phantom undergoing HDR brachytherapy applied to localized prostate carcinoma.Med Phys. 2013; : 033901
- Dosimetric perturbation of a lead shield used for surface and interstitial high-dose-rate brachytherapy.J Radiol Prot. 2014; 34: 297-311
- Dosimetric perturbations at high-Z interfaces with high dose rate 192Ir source.Phys Med. 2014; 30: 782-790
- Fetal position and size data for dose estimation.Br J Radiol. 1999; 72: 363-370
- Dose-response curve of EBT, EBT2, and EBT3 radiochromic films to synchrotron-produced monochromatic x-ray beams.Med Phys. 2012; 39: 7412-7417
- An efficient protocol for radiochromic film dosimetry combining calibration and measurement in a single scan.Med Phys. 2012; 39: 6339-6350
- Evaluation of current consensus statement recommendations for accelerated partial breast irradiation: a pooled analysis of William Beaumont Hospital an American Society of Breast Surgeon Mammosite Registry Trial Data.Int J Radiat Oncol Biol Phys. 2013; 85: 1179-1185
- Photon-beam radiotherapy in pregnant patients: can the fetal dose be limited to 10 cGy or less?.Phys Med. 2015; 31: 85-91
- Radiation-induced cataracts: the HEALTH Protection Agency's response to the ICRP statement on tissue reactions and recommendations on the dose limit for the eye lens.J Radiol Prot. 2012; 32: 479-488
- (Ottawa, Canada)ICRP issues statement lowering threshold for eye lens. 2011 ([accessed January 14.01.15])
- Comparison of organ doses for patients undergoing balloon brachytherapy of the breast with HDR 192Ir or electronic sources using Monte Carlo simulations in a heterogeneous human phantom.Med Phys. 2010; 37: 662-671
Article info
Publication history
Published online: February 10, 2015
Accepted:
January 20,
2015
Received in revised form:
January 19,
2015
Received:
November 1,
2014
Identification
Copyright
© 2015 Associazione Italiana di Fisica Medica. Published by Elsevier Inc. All rights reserved.
