Journal of Radiation Protection and Research

The Korean Association for Radiation Protection (대한방사선방어학회)
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Cross Talk Experiment with Two-element CdTe Detector and Collimator for BNCT-SPECT

  • Received : 2016.05.12
  • Accepted : 2016.09.12
  • Published : 2016.12.31
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Abstract

Background: Boron Neutron Capture Therapy (BNCT) is a new radiation therapy. In BNCT, there exists some very critical problems that should be solved. One of the severest problems is that the treatment effect cannot be known during BNCT in real time. We are now developing a SPECT (single photon emission computed tomography) system (BNCT-SPECT), with a cadmium telluride (CdTe) semiconductor detector. BNCT-SPECT can obtain the BNCT treatment effect by measuring 478 keV gamma-rays emitted from the excited state of $^7Li$ nucleus created by $^{10}B(n,{\alpha})$ $^7Li$ reaction. In the previous studies, we investigated the feasibility of the BNCT-SPECT system. As a result, the S/N ratio did not meet the criterion of S/N > 1 because deterioration of the S/N ratio occurred caused by the influence of Compton scattering especially due to capture gamma-rays of hydrogen. Materials and Methods: We thus produced an arrayed detector with two CdTe crystals to test cross talk phenomenon and to examine an anti-coincidence detection possibility. For more precise analysis for the anti-coincidence detection, we designed and made a collimator having a similar performance to the real BNCT-SPECT. Results and Discussion: We carried out experiments with the collimator to examine the effect of cross talk of scattering gamma-rays between CdTe elements more practically. As a result of measurement the coincidence events were successfully extracted. Conclusion: We are now planning to carry out evaluation of coincidence rate from the measurement and comparison of it with the numerical calculations.

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References

  1. Kobayashi T, Sakurai Y, Ishikawa M. Anoninvasive dose estimation system for clinical BNCT based on PG-SPECT-Conceptual study and fundamental experiments using HPGe and CdTe semiconductor detectors. Med. Phys. 2000; 27(9): 2124-2132. https://doi.org/10.1118/1.1288243
  2. Minsky DM, Valda AA, Kreiner AJ, Green S, Wojnecki C, Ghani Z. Experimental feasibility studies on a SPECT tomograph for BNCT dosimetry. Appl. Radiat. Isot. 2009;67:S179-S182. https://doi.org/10.1016/j.apradiso.2009.03.044
  3. Rosenschold P. M, Minarik D, Ostlund C, Ljungberg M, Ceberg C. Prompt gamma tomography during BNCT-A feasibility study. J. Instrum. 2006;1:wP05003.
  4. Katabuchi T, Hales B, Hayashizaki N, Igashira M, Khan Z, Kobayashi T, Matsuhashi T, MiyazakiK, Ogawa K, Terada K. Feasibility study on pinhole camera system for online dosimetry in boron neutron capture therapy. Appl. Radiat. Isot. 2014;88:139-142. https://doi.org/10.1016/j.apradiso.2013.12.026
  5. Murata I, Mukai T, Ito M, Miyamaru H, Yoshida S. Feasibility study on BNCT-SPECT using a CdTe detector. Progress in Nucl. Sci. Technol. 2011;1:267-270. https://doi.org/10.15669/pnst.1.267
  6. Manabe M, Nakamura S, Murata I. Present status of BNCTSPECT development with CdTe detector. Proc. of the 2013 Symposium on Nuclear Data, Nov.14-15,Fukui, Japan JAEA-Conference 2014. 2015;002:198-203.
  7. Mukai T, Murata I, Ito M, Miyamaru H. Development of CdTe detector for BNCT-SPECT. Proc. of the 2009 Annual Symposium on Nucl. Data, Nov. 26-27, 2009, RICOTTI, Tokai-mura, Ibarakiken, Japan. JAEA-Conference. 2010;005:75-80.
  8. Murata I, Mukai T, Nakamura S, Miyamaru H, Kato I. Development of a thick CdTe detector for BNCT-SPECT. Appl. Radiat. Isot. 2011;69:1706-1709. https://doi.org/10.1016/j.apradiso.2011.05.014
  9. Nakamura S, Mukai T, Manabe M, Murata I. Characterization test of CdTe detector element designed and developed for BNCT-SPECT. Proc. of the 2011 Annual Symposium on Nucl. Data, Nov. 16-17, 2011, RICOTTI, Tokai-mura, Ibaraki-ken, Japan. JAEA-Conference. 2012;001:165-170.
  10. Manabe M, Nakamura S, Murata I. Study on measuring device arrangement of array-type CdTe Detector for BNCT-SPECT. Rep. Pract. Oncol. Radiother. 2016;21(2):102-107. https://doi.org/10.1016/j.rpor.2015.04.002
  11. Manabe M, Sato F, Murata I. Basic detection property of an array-type CdTe detector for BNCT-SPECT-Measurement and analysis of anti-coincidence events-. Appl. Radiat. Isot. 2016;118: 389-394. https://doi.org/10.1016/j.apradiso.2015.11.003