Development of Optical Fiber Based Measurement System for the Verification of Entrance Dose Map in Pencil Beam Scanning Proton Beam

This study describes the development of a beam monitoring system for the verification of entrance dose map in pencil beam scanning (PBS) proton therapy based on fiber optic radiation sensors (FORS) and the validation of this system through a feasibility study. The beam monitoring system consisted of 128 optical fibers optically coupled to photo-multiplier tubes. The performance of the beam monitoring system based on FORS was verified by comparing 2D dose maps of square-shaped fields of various sizes, which were obtained using conventional dosimeters such as MatriXX and EBT3 film, with those measured using FORS. The resulting full-width at half maximum and penumbra were compared for PBS proton beams, with a ≤2% difference between each value, indicating that measurements using the conventional dosimetric tool corresponded to measurements based on FORS. For irregularly-shaped fields, a comparison based on the gamma index between 2D dose maps obtained using MatriXX and EBT3 film and the 2D dose map measured by the FORS showed passing rates of 96.9 ± 1.3% and 96.2 ± 1.9%, respectively, confirming that FORS-based measurements for PBS proton therapy agreed well with those measured using the conventional dosimetric tools. These results demonstrate that the developed beam monitoring system based on FORS is good candidate for monitoring the entrance dose map in PBS proton therapy.

[1]  Cinzia Talamonti,et al.  A new approach in patient QA: Beam delivery check and in-vivo dosimetry during radiotherapy treatment , 2016 .

[2]  T Kanai,et al.  Spot scanning system for proton radiotherapy. , 1980, Medical physics.

[3]  Rajat J Kudchadker,et al.  LiF TLD-100 as a dosimeter in high energy proton beam therapy--can it yield accurate results? , 2010, Medical dosimetry : official journal of the American Association of Medical Dosimetrists.

[4]  T. Inada,et al.  [Proton therapy]. , 1989, Radioisotopes.

[5]  Myonggeun Yoon,et al.  Development of a novel proton dosimetry system using an array of fiber-optic Cerenkov radiation sensors. , 2015, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.

[6]  Jarod C Finlay,et al.  Proton therapy dosimetry using the scintillation of the silica fibers. , 2017, Optics letters.

[7]  Jarod C Finlay,et al.  The visible signal responsible for proton therapy dosimetry using bare optical fibers is not Čerenkov radiation. , 2016, Medical physics.

[8]  L. Beaulieu,et al.  Real-time verification of multileaf collimator-driven radiotherapy using a novel optical attenuation-based fluence monitor. , 2011, Medical physics.

[9]  Harald Paganetti,et al.  Relative biological effectiveness (RBE) values for proton beam therapy. , 2002, International journal of radiation oncology, biology, physics.

[10]  John Wong,et al.  SU-E-T-483: In Vivo Dosimetry of Conventional and Rotational Intensity Modulated Radiotherapy Using Integral Quality Monitor (IQM) , 2015 .

[11]  Frederik Wenz,et al.  Characterization of a new transmission detector for patient individualized online plan verification and its influence on 6MV X-ray beam characteristics. , 2016, Zeitschrift fur medizinische Physik.

[12]  Wook Jae Yoo,et al.  Fiber-optic Cerenkov radiation sensor for proton therapy dosimetry. , 2012, Optics express.

[13]  Michael Gillin,et al.  Use of a two-dimensional ionization chamber array for proton therapy beam quality assurance. , 2008, Medical physics.

[14]  E. Pedroni,et al.  The 200-MeV proton therapy project at the Paul Scherrer Institute: conceptual design and practical realization. , 1995, Medical physics.

[15]  J J Wilkens,et al.  Comparison of Gafchromic EBT2 and EBT3 films for clinical photon and proton beams. , 2012, Medical physics.

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

[17]  Richard Pötter,et al.  Treatment planning comparison of conventional, 3D conformal, and intensity-modulated photon (IMRT) and proton therapy for paranasal sinus carcinoma. , 2004, International journal of radiation oncology, biology, physics.

[18]  M Engelsman,et al.  Commissioning a passive-scattering proton therapy nozzle for accurate SOBP delivery. , 2009, Medical physics.

[19]  Uwe Titt,et al.  Commissioning of the discrete spot scanning proton beam delivery system at the University of Texas M.D. Anderson Cancer Center, Proton Therapy Center, Houston. , 2009, Medical physics.

[20]  M. Langer,et al.  Optimization of beam weights under dose-volume restrictions. , 1987, International journal of radiation oncology, biology, physics.

[21]  Jarod C Finlay,et al.  Spectroscopic separation of Čerenkov radiation in high-resolution radiation fiber dosimeters , 2015, Journal of biomedical optics.

[22]  Young Hoon Ji,et al.  Dosimetric evaluation of a glass dosimeter for proton beam measurements. , 2012, Applied radiation and isotopes : including data, instrumentation and methods for use in agriculture, industry and medicine.

[23]  D. Low,et al.  A technique for the quantitative evaluation of dose distributions. , 1998, Medical physics.

[24]  Cedric X. Yu,et al.  Intensity-modulated arc therapy with dynamic multileaf collimation: an alternative to tomotherapy. , 1995, Physics in medicine and biology.

[25]  H. Kooy,et al.  Proton beam therapy , 2005, British Journal of Cancer.

[26]  Alfred R. Smith.  REVIEW: Proton therapy , 2006 .

[27]  Frederik Wenz,et al.  Patient-specific online dose verification based on transmission detector measurements. , 2016, Radiotherapy and oncology : journal of the European Society for Therapeutic Radiology and Oncology.