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
. 2016 Mar-Apr;49(2):92-7.
doi: 10.1590/0100-3984.2015.0010.

Balloon-based adjuvant radiotherapy in breast cancer: comparison between (99m)Tc and HDR (192)Ir

Tarcísio Passos Ribeiro de Campos  1 , Carla Flavia de Lima  2 , Ethel Mizrahy Cuperschmid  3
Affiliations

Balloon-based adjuvant radiotherapy in breast cancer: comparison between (99m)Tc and HDR (192)Ir

Tarcísio Passos Ribeiro de Campos et al. Radiol Bras. 2016 Mar-Apr.

Abstract
in English, Portuguese

Objective: To perform a comparative dosimetric analysis, based on computer simulations, of temporary balloon implants with (99m)Tc and balloon brachytherapy with high-dose-rate (HDR) (192)Ir, as boosts to radiotherapy. We hypothesized that the two techniques would produce equivalent doses under pre-established conditions of activity and exposure time.

Materials and methods: Simulations of implants with (99m)Tc-filled and HDR (192)Ir-filled balloons were performed with the Siscodes/MCNP5, modeling in voxels a magnetic resonance imaging set related to a young female. Spatial dose rate distributions were determined. In the dosimetric analysis of the protocols, the exposure time and the level of activity required were specified.

Results: The (99m)Tc balloon presented a weighted dose rate in the tumor bed of 0.428 cGy.h(-1).mCi(-1) and 0.190 cGyh(-1).mCi(-1) at the balloon surface and at 8-10 mm from the surface, respectively, compared with 0.499 and 0.150 cGyh(-1).mCi(-1), respectively, for the HDR (192)Ir balloon. An exposure time of 24 hours was required for the (99m)Tc balloon to produce a boost of 10.14 Gy with 1.0 Ci, whereas only 24 minutes with 10.0 Ci segments were required for the HDR (192)Ir balloon to produce a boost of 5.14 Gy at the same reference point, or 10.28 Gy in two 24-minutes fractions.

Conclusion: Temporary (99m)Tc balloon implantation is an attractive option for adjuvant radiotherapy in breast cancer, because of its availability, economic viability, and similar dosimetry in comparison with the use of HDR (192)Ir balloon implantation, which is the current standard in clinical practice.

Objetivo: Análise dosimétrica comparativa entre técnicas de implantes temporários de reforço por meio de balões de 99mTc e de 192Ir de alta taxa de dose (high dose rate - HDR) mediante simulação computacional. A hipótese é que ambos produzem dosimetria equivalente em condições pré-estabelecidas de atividade e exposição.

Materiais e métodos: Simulações de implantes com balão preenchido com 99mTc e balão HDR-192Ir foram elaboradas no Siscodes/ MCNP5, modelando em voxels um tórax feminino reproduzido de ressonância magnética de mama jovem. Distribuições espaciais de taxas de dose absorvidas foram geradas. Análises dosimétricas dos protocolos foram apresentadas especificando tempo acumulado e atividade requerida.

Resultados: Implante temporário com balão-99mTc apresentou taxa de dose ponderada no leito do tumor, na adjacência do balão, de 0,428 cGyh-1.mCi-1, e a 8-10 mm distante, de 0,190 cGyh-1.mCi-1, enquanto o implante de balão com 192Ir apresentou 0,499 e 0,150 cGyh-1.mCi-1, respectivamente. A exposição de 24 horas para balão-99mTc foi necessária para produzir o reforço de 10,14 Gy com 1,0 Ci, ao passo que para balão HDR-192Ir foram necessários 24 minutos com segmentos de 10,0 Ci para gerar 5,14 Gy no mesmo ponto de referência, ou 10,28 Gy em duas frações de 24 minutos.

Conclusão: Implante temporário com balão-99mTc é atrativo para a radioterapia adjuvante do câncer de mama, devido a disponibilidade, viabilidade econômica e equivalência radiodosimétrica ao balão HDR-192Ir, protocolo presente na prática clínica.

Keywords: 192Ir; 99mTc; Balloon; Balão; Braquiterapia de mama; Breast brachytherapy; Monte Carlo method; Método Monte Carlo; Radioterapia adjuvante; Radiotherapy dosage; Radiotherapy, adjuvant; Reforço de dose.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Spatial distribution of normalized dose rate in relation to the activity, shown in lateral, sagittal, and axial slices, induced by brachytherapy with a 192Irfilled balloon.
Figure 2
Figure 2
Spatial distribution of normalized dose rate in relation to the activity, shown in lateral, sagittal, and axial slices, induced by implantation of a balloon with a homogeneously distributed source of 99mTc.
See this image and copyright information in PMC

References

    1. IARC . Estimated cancer incidence, mortality and prevalence worldwide in 2012. International Agency for Research on Cancer, World Health Organization; [cited 2014 June 12]. Available from: globocan.iarc.fr.
    1. Brasil. Ministério da Saúde. Instituto Nacional de Câncer José Alencar Gomes da Silva . Estatísticas do câncer: vigilância do câncer e fatores de risco. [cited 2014 June 12]. Available from: http://www.inca.gov.br.
    1. Godinho ER, Koch HA. Rastreamento do câncer de mama: aspectos relacionados ao médico. Radiol Bras. 2004;37:91–99.
    1. Roychoudhuri R, Evans H, Robinson D, et al. Radiation-induced malignancies following radiotherapy for breast cancer. Br J Cancer. 2004;91:868–872. - PMC - PubMed
    1. Purdy JA. Three dimensional physics and treatment planning. In: Perez CA, Brady LW, editors. Principles and practice of radiation oncology. 3rd ed. Philadelphia, PA: Lippincott-Raven; 1998. pp. 343–370.

LinkOut - more resources