Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Comparative Study
. 2010 Feb;37(2):662-71.
doi: 10.1118/1.3292292.

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

Matthew M Mille  1 , X George Xu, Mark J Rivard
Affiliations
Comparative Study

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

Matthew M Mille et al. Med Phys. 2010 Feb.

Abstract

Purpose: Accelerated partial breast irradiation via interstitial balloon brachytherapy is a fast and effective treatment method for certain early stage breast cancers. The radiation can be delivered using a conventional high-dose rate (HDR) 192Ir gamma-emitting source or a novel electronic brachytherapy (eBx) source which uses lower energy x rays that do not penetrate as far within the patient. A previous study [A. Dickler, M. C. Kirk, N. Seif, K. Griem, K. Dowlatshahi, D. Francescatti, and R. A. Abrams, "A dosimetric comparison of MammoSite high-dose-rate brachytherapy and Xoft Axxent electronic brachytherapy," Brachytherapy 6, 164-168 (2007)] showed that the target dose is similar for HDR 192Ir and eBx. This study compares these sources based on the dose received by healthy organs and tissues away from the treatment site.

Methods: A virtual patient with left breast cancer was represented by a whole-body, tissue-heterogeneous female voxel phantom. Monte Carlo methods were used to calculate the dose to healthy organs in a virtual patient undergoing balloon brachytherapy of the left breast with HDR 192Ir or eBx sources. The dose-volume histograms for a few organs which received large doses were also calculated. Additional simulations were performed with all tissues in the phantom defined as water to study the effect of tissue inhomogeneities.

Results: For both HDR 192Ir and eBx, the largest mean organ doses were received by the ribs, thymus gland, left lung, heart, and sternum which were close to the brachytherapy source in the left breast, eBx yielded mean healthy organ doses that were more than a factor of approximately 1.4 smaller than for HDR 192Ir for all organs considered, except for the three closest ribs. Excluding these ribs, the average and median dose-reduction factors were approximately 28 and approximately 11, respectively. The volume distribution of doses in nearby soft tissue organs that were outside the PTV were also improved with eBx. However, the maximum dose to the closest rib with the eBx source was 5.4 times greater than that of the HDR 192Ir source. The ratio of tissue-to-water maximum rib dose for the eBx source was approximately 5.

Conclusions: The results of this study indicate that eBx may offer lower toxicity to most healthy tissues, except nearby bone. TG-43 methods have a tendency to underestimate dose to bone, especially the ribs. Clinical studies evaluating the negative health effects caused by irradiating healthy organs are needed so that physicians can better understand when HDR 192Ir or eBx might best benefit a patient.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Half-skinned trimetric view of the RPI-adult female phantom showing the detailed internal bone, muscle, and organ structures.
Figure 2
Figure 2
Isodose lines for 100%, 50%, 25%, and 5% of the 34 Gy prescription dose are shown on top of a grayscale image depicting the various organs within the phantom: (a) HDR 192Ir in tissue; (b) 50 kVp eBx in tissue; (c) HDR 192Ir in water; and (d) 50 kVp eBx in water. The brachytherapy balloon is shown in the left breast.
Figure 3
Figure 3
The radial dose functions for the HDR 192Ir and 50 kVp eBx sources used in this study. The data are in good agreement with experimental and Monte Carlo calculated data found in the literature (Refs. 11, 33).
Figure 4
Figure 4
Comparison of the organ doses received by the RPI-adult female phantom during a balloon brachytherapy of the left breast involving the HDR 192Ir and 50 kVp eBx sources. The results are shown as a ratio of the HDR 192Ir doses relative to the eBx doses for both the tissue and water phantoms.
Figure 5
Figure 5
Comparison of the organ doses received by the RPI-adult female phantom with tissue heterogeneities and with all tissues defined as water. The results are shown as a ratio of the tissue phantom doses relative to the water phantom doses for both the HDR 192Ir and 50 kVp eBx sources.
Figure 6
Figure 6
Dose-volume histograms for the tissue and water phantoms. (a) Left lung (ipsilateral); (b) heart (wall and contents); (c) rib4 (ipsilateral); and (d) thymus. The dose-volume histogram of rib4 for the HDR 192Ir source in the water phantom is not shown because it is indistinguishable from the tissue phantom histogram shown in plot (c).
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Belkacémi Y., Hannoun-Lévi J. M., and Lartigau E., in New Technologies in Radiation Oncology, edited by Schlegel W., Bortfeld T., and Grosu A. -L. (Springer, New York, 2006), pp. 397–407.10.1007/3-540-29999-8_31 - DOI
    1. Smith B. D., Arthur D. W., Buchholz T. A., Haffty B. G., Hahn C. A., Hardenbergh P. H., Julian T. B., Marks L. B., Todor D. A., Vicini F. A., Whelan T. J., White J., Wo J. Y., and Harris J. R., “Accelerated partial breast irradiation consensus statement from the American society for radiation oncology (ASTRO),” Int. J. Radiat. Oncol., Biol., Phys. IOBPD3 74, 987–1001 (2009). - PubMed
    1. Stewart A. J., O’Farrell D. A., Cormack R. A., Hansen J. L., Khan A. J., Mutyala S., and Devlin P. M., “Dose volume histogram analysis of normal structures associated with accelerated partial breast irradiation delivered by high dose rate brachytherapy and comparison with whole breast external beam radiotherapy fields,” Radiat. Oncol. 3(39) (2008).10.1186/1748-717X-3-39 - DOI - PMC - PubMed
    1. Adkison J. B., Kuske R. R., Quiet C. A., Beriwal S., and Patel R. R., “Five-year results of accelerated partial breast irradiation for ductal carcinoma in situ treated by interstitial multicatheter high-dose-rate brachytherapy or MammoSite,” Brachytherapy BRACC4 8, 107–108 (2009).10.1016/j.brachy.2009.03.013 - DOI
    1. Adkison J. B., Patel R. R., Beriwal S., Quiet C. A., and Kuske R. R., “Five-year results for accelerated partial breast irradiation using MammoSite balloon brachytherapy: The first 100 patients,” Brachytherapy BRACC4 7, 104 (2008).10.1016/j.brachy.2008.02.371 - DOI

Publication types