Improved Beam Angle Arrangement in Intensity Modulated Proton Therapy Treatment Planning for Localized Prostate Cancer

Purpose: This study investigates potential gains of an improved beam angle arrangement compared to a conventional fixed gantry setup in intensity modulated proton therapy (IMPT) treatment for localized prostate cancer patients based on a proof of principle study. Materials and Methods: Three patients with localized prostate cancer retrospectively selected from our institution were studied. For each patient, IMPT plans were designed using two, three and four beam angles, respectively, obtained from a beam angle optimization algorithm. Those plans were then compared with ones using two lateral parallel-opposed beams according to the conventional planning protocol for localized prostate cancer adopted at our institution. Results: IMPT plans with two optimized angles achieved significant improvements in rectum sparing and moderate improvements in bladder sparing against those with two lateral angles. Plans with three optimized angles further improved rectum sparing significantly over those two-angle plans, whereas four-angle plans found no advantage over three-angle plans. A possible three-beam class solution for localized prostate patients was suggested and demonstrated with preserved dosimetric benefits because individually optimized three-angle solutions were found sharing a very similar pattern. Conclusions: This study has demonstrated the potential of using an improved beam angle arrangement to better exploit the theoretical dosimetric benefits of proton therapy and provided insights of selecting quality beam angles for localized prostate cancer treatment.

[1]  A J Lomax,et al.  Proton range verification using a range probe: definition of concept and initial analysis , 2010, Physics in medicine and biology.

[2]  Steven E Schild,et al.  Re: Proton vs intensity-modulated radiotherapy for prostate cancer: patterns of care and early toxicity. , 2013, Journal of the National Cancer Institute.

[3]  George Starkschall,et al.  Late rectal toxicity: dose-volume effects of conformal radiotherapy for prostate cancer. , 2002, International journal of radiation oncology, biology, physics.

[4]  Ronald C. Chen,et al.  Intensity-modulated radiation therapy, proton therapy, or conformal radiation therapy and morbidity and disease control in localized prostate cancer. , 2012, JAMA.

[5]  A. Lomax,et al.  Intensity modulation methods for proton radiotherapy. , 1999, Physics in medicine and biology.

[6]  Bijan Arjomandy,et al.  Patient-specific quality assurance for prostate cancer patients receiving spot scanning proton therapy using single-field uniform dose. , 2011, International journal of radiation oncology, biology, physics.

[7]  Cary P Gross,et al.  Proton versus intensity-modulated radiotherapy for prostate cancer: patterns of care and early toxicity. , 2013, Journal of the National Cancer Institute.

[8]  Feliciano García-Vicente,et al.  Impact of mean rectal dose on late rectal bleeding after conformal radiotherapy for prostate cancer: dose-volume effect. , 2003, International journal of radiation oncology, biology, physics.

[9]  J. Deasy,et al.  Radiation dose-volume effects in radiation-induced rectal injury. , 2010, International journal of radiation oncology, biology, physics.

[10]  Radhe Mohan,et al.  Effect of anatomic motion on proton therapy dose distributions in prostate cancer treatment. , 2007, International journal of radiation oncology, biology, physics.

[11]  Shikui Tang,et al.  Improvement of prostate treatment by anterior proton fields. , 2012, International journal of radiation oncology, biology, physics.

[12]  Anders Forsgren,et al.  Minimax optimization for handling range and setup uncertainties in proton therapy. , 2011, Medical physics.

[13]  R Miralbell,et al.  Potential role of intensity modulated proton beams in prostate cancer radiotherapy. , 2001, International journal of radiation oncology, biology, physics.

[14]  Thomas Bortfeld,et al.  Reducing the sensitivity of IMPT treatment plans to setup errors and range uncertainties via probabilistic treatment planning. , 2008, Medical physics.

[15]  Radhe Mohan,et al.  Robust optimization of intensity modulated proton therapy. , 2012, Medical physics.

[16]  Wei Liu,et al.  Uncertainty incorporated beam angle optimization for IMPT treatment planning. , 2012, Medical physics.

[17]  W. Shih,et al.  Late gastrointestinal toxicities following radiation therapy for prostate cancer. , 2011, European urology.

[18]  Alessandra Bolsi,et al.  Treatment planning and verification of proton therapy using spot scanning: initial experiences. , 2004, Medical physics.

[19]  Hsiao-Ming Lu,et al.  A potential method for in vivo range verification in proton therapy treatment , 2008, Physics in medicine and biology.

[20]  Wei Chen,et al.  Including robustness in multi-criteria optimization for intensity-modulated proton therapy , 2011, Physics in medicine and biology.

[21]  D Robertson,et al.  Intensity modulated proton therapy treatment planning using single-field optimization: the impact of monitor unit constraints on plan quality. , 2010, Medical physics.

[22]  A J Lomax,et al.  Intensity modulated proton therapy and its sensitivity to treatment uncertainties 2: the potential effects of inter-fraction and inter-field motions , 2008, Physics in medicine and biology.

[23]  Rajat J Kudchadker,et al.  A comprehensive comparison of IMRT and VMAT plan quality for prostate cancer treatment. , 2012, International journal of radiation oncology, biology, physics.

[24]  Wei Liu,et al.  Influence of robust optimization in intensity-modulated proton therapy with different dose delivery techniques. , 2012, Medical physics.

[25]  Gudrun Goitein,et al.  The clinical potential of intensity modulated proton therapy. , 2004, Zeitschrift fur medizinische Physik.

[26]  Gregory C Sharp,et al.  In vivo proton beam range verification using spine MRI changes. , 2010, International journal of radiation oncology, biology, physics.

[27]  C. Lawton Long-term toxicity following 3D conformal radiation therapy for prostate cancer from the RTOG 9406 phase I/II dose escalation study , 2011 .

[28]  Alexei Trofimov,et al.  Radiotherapy treatment of early-stage prostate cancer with IMRT and protons: a treatment planning comparison. , 2007, International journal of radiation oncology, biology, physics.

[29]  A. Lomax,et al.  Intensity modulated proton therapy and its sensitivity to treatment uncertainties 1: the potential effects of calculational uncertainties , 2008, Physics in medicine and biology.

[30]  C. Fiorino,et al.  Clinical and dosimetric predictors of late rectal toxicity after conformal radiation for localized prostate cancer: results of a large multicenter observational study. , 2009, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[31]  U Oelfke,et al.  Worst case optimization: a method to account for uncertainties in the optimization of intensity modulated proton therapy , 2008, Physics in medicine and biology.