IJMPCERO  Vol.4 No.1 , February 2015
Intensity Modulated Proton Therapy as a Boost Treatment after Prostate Seed Implant: A Treatment Planning Study
Purpose: Combination of Prostate Seed Implant (PSI) with External Beam Radiation Therapy (EBRT) remains as an attractive option for patients with intermediate or high-risk prostate cancer. One of the most widely used approaches is to use external beam radiation therapy (EBRT) to deliver boost doses after permanent prostate seed implant (PSI). In this study, the feasibility of using Intensity Modulated Proton Therapy (IMPT) as an alternative EBRT boost treatment for PSI patients was investigated in the presence of a large number of high Z metallic seeds. The dosimetry of IMPT boost plans was compared with that of conventional Intensity Modulated Radiation Therapy (IMRT) boost plans. Methods: Ten post prostate seed implants with seeds of I-125 were randomly selected for this study. Proton treatment plans were created with two lateral opposed proton beams in Eclipse treatment planning system. IMRT boost plans were generated with seven co-planner beams for comparison. Several plan evaluation parameters such as the planning target volume (PTV) dose homogeneity, dose conformity and dose to surrounding normal tissues were evaluated. Results: Compared to conventional IMRT boost plans, IMPT demonstrated better sparing of normal tissues while providing similar satisfactory PTV coverage. The high Z implanted seeds is not a problem for IMPT as boost treatment. Conclusions: PSI with an IMPT boost can be a valuable option for prostate cancer patient treatment. It delivers comparable or better radiation dose distribution in terms of normal tissue sparing compared to IMRT boost plan.
Cite this paper: Wu, J. , Wu, H. and Cheng, C. (2015) Intensity Modulated Proton Therapy as a Boost Treatment after Prostate Seed Implant: A Treatment Planning Study. International Journal of Medical Physics, Clinical Engineering and Radiation Oncology, 4, 76-83. doi: 10.4236/ijmpcero.2015.41011.

[1]   Jani, A.B., Hand, C.M., Lujan, A.E., Roeske, J.C., Zagaja, G.P., Vijayakumar, S. and Pelizzari, C.A. (2004) Biological Effective Dose for Comparison and Combination of External Beam and Low-Dose Rate Interstitial Brachytherapy Prostate Cancer Treatment Plans. Medical Dosimetry, 29, 42-48.

[2]   Zaider, M., Zelefsky, M.J., Cohen, G.N., Chui, C.-S., Yorke, E.D., Ben-Porat, L. and Happersett, L. (2005) Methodology for Biologically-Based Treatment Planning for Combined Low-Dose-Rate (Permanent Implant) and High-Dose-Rate (Fractionated) Treatment of Prostate Cancer. International Journal of Radiation Oncology Biology Physics, 61, 702-713.

[3]   Zelefsky, M.J., Nedelka, M.A., Arican, Z.-L., Yamada, Y., Cohen, G.N., Shippy, A.M., Park, J.J. and Zaider, M. (2008) Combined Brachytherapy with External Beam Radiotherapy for Localized Prostate Cancer: Reduced Morbidity with an Intraoperative Brachytherapy Planning Technique and Supplemental Intensity-Modulated Radiation Therapy. Brachytherapy, 7, 1-6.

[4]   Zilli, T., Boudreau, C., Filion, E.J., Donath, D. and Taussky, D. (2011) Combined Intensity-Modulated Radiation Therapy vs. Three-Dimensional Highly Conformal Radiotherapy after 125I Prostate Permanent Seed Brachytherapy: A Comparative Treatment Planning Study. Brachytherapy, 10, 416-420.

[5]   Cao, M., Ko, S.-C., Slessinger, E.D., DesRosiers, C.M., Johnstone, P.A. and Das, I.J. (2011) A Simple Method for Dose Fusion from Multimodality Treatment of Prostate Cancer: Brachytherapy to External Beam Therapy. Brachytherapy, 10, 214-220.

[6]   Albert, M., Tempany, C.M., Schultz, D., Chen, M.-H., Cormack, R.A., Kumar, S., et al. (2003) Late Genitourinary and Gastrointestinal Toxicity after Magnetic Resonance Image-Guided Prostate Brachytherapy with or without Neoadjuvant External Beam Radiation Therapy. Cancer, 98, 949-954.

[7]   Sarosdy, M.F. (2004) Urinary and Rectal Complications of Contemporary Permanent Transperineal Brachytherapy for Prostate Carcinoma with or without External Beam Radiation Therapy. Cancer, 101, 754-760.

[8]   Zeitlin, S.I., Sherman, J., Raboy, A., Lederman, G. and Albert, P. (1998) High Dose Combination Radiotherapy for the Treatment of Localized Prostate Cancer. The Journal of Urology, 160, 91-95; discussion 95-96.

[9]   Lomax, A.J., Boehringer, T., Coray, A., Egger, E., Goitein, G., Grossmann, M., et al. (2001) Intensity Modulated Proton Therapy: A Clinical Example. Medical Physics, 28, 317-324.

[10]   Polo, A., Salembier, C., Venselaar, J. and Hoskin, P. (2010) Review of Intraoperative Imaging and Planning Techniques in Permanent Seed Prostate Brachytherapy. Radiotherapy and Oncology, 94, 12-23.

[11]   Bucci, J., Spadinger, I., Hilts, M., Sidhu, S., Smith, C., Keyes, M. and James Morris, W. (2002) Urethral and Periurethral Dosimetry in Prostate Brachytherapy: Is There a Convenient Surrogate? International Journal of Radiation Oncology*Biology*Physics, 54, 1235-1242.

[12]   Nakamura, J.L., Verhey, L.J., Smith, V., Petti, P.L., Lamborn, K.R., Larson, D.A., et al. (2001) Dose Conformity of Gamma Knife Radiosurgery and Risk Factors for Complications. International Journal of Radiation Oncology*Biology*Physics, 51, 1313-1319.

[13]   Paddick, I. (2000) A Simple Scoring Ratio to Index the Conformity of Radiosurgical Treatment Plans. Technical Note. Journal of Neurosurgery, 93, 219-222.

[14]   Hall, E.J. and Wuu, C.S. (2003) Radiation-Induced Second Cancers: The Impact of 3D-CRT and IMRT. International Journal of Radiation Oncology*Biology*Physics, 56, 83-88.

[15]   Newhauser, W., Fontenot, J., Koch, N., Dong, L., Lee, A., Zheng, Y.S., et al. (2007) Monte Carlo Simulations of the Dosimetric Impact of Radiopaque Fiducial Markers for Proton Radiotherapy of the Prostate. Physics in Medicine and Biology, 52, 2937-2952.

[16]   Newhauser, W.D., Koch, N.C., Fontenot, J.D., Rosenthal, S.J., Gombos, D.S., Fitzek, M.M. and Mohan, R. (2007) Dosimetric Impact of Tantalum Markers Used in the Treatment of Uveal Melanoma with Proton Beam Therapy. Physics in Medicine and Biology, 52, 3979-3790.

[17]   Mendenhall, N.P., Malyapa, R.S., Su, Z., Yeung, D., Mendenhall, W.M. and Li, Z.F. (2011) Proton Therapy for Head and Neck Cancer: Rationale, Potential Indications, Practical Considerations, and Current Clinical Evidence. Acta Oncologica, 50, 763-771.

[18]   Yohannes, I., Kolditz, D., Langner, O. and Kalender, W.A. (2012) A Formulation of Tissue- and Water-Equivalent Materials Using the Stoichiometric Analysis Method for CT-Number Calibration in Radiotherapy Treatment Planning. Physics in Medicine and Biology, 57, 1173-1190.

[19]   Schaffner, B. and Pedroni, E. (1998) The Precision of Proton Range Calculations in Proton Radiotherapy Treatment Planning: Experimental Verification of the Relation between CT-HU and Proton Stopping Power. Physics in Medicine and Biology, 43, 1579-1592.

[20]   Cheng, C.-W., Zhao, L., Wolanski, M., Zhao, Q.Y., James, J., Dikeman, K., et al. (2013) Comparison of Tissue Characterization Curves for Different CT Scanners: Implication in Proton Therapy Treatment Planning. Translational Cancer Research, 1, 236-246.