Dosimetric Study in Tomotherapy Based on AAPM TG 119 Structures: A Longitudinal Moving Phantom Case

Document Type : Original Paper

Authors

1 Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, West Java, 16424, Indonesia Department of Radiotherapy, Cipto Mangunkusumo General Hospital, Jakarta, 10430, Indonesia

2 Department of Radiotherapy, Cipto Mangunkusumo General Hospital, Jakarta, 10430, Indonesia

3 Transmedik Indonesia, Jakarta, 10410, Indonesia

4 Department of Physics, Faculty of Mathematics and Natural Sciences, Universitas Indonesia, Depok, West Java, 16424, Indonesia

Abstract

Introduction: Tomotherapy beam delivery is in the helical form. Therefore, the dose distribution will be more complex while target is moving. In this study, we sought to evaluate the dosimetric impact due to longitudinal motion in the phantom of a tomotherapy machine.         
Material and Methods: Cheese and Delta4 phantom+ were placed on a respiratory motion platform. They moved in longitudinal directions at the amplitudes of 2, 4, 6, 8, and 10 mm. The period of that movement was 4 and 6 s with the field widths of 25 and 50 mm, respectively. The C-shaped complex target was modified according to the American Association of Physicists in Medicine (AAPM) Task Group (TG) 119. The planning verifications were evaluated through point dose, gamma index value, and dose-volume histogram (DVH).
Results: Discrepancy of the dose measurements ranged from -1.254 to -14.421%. The range of gamma index value was 61.2 ±1.23% to 100±0.00. The DVH evaluation showed that the homogeneity index (HI) and the minimum dose to receive by 95% (D95%)  of the target structure were 0.247 to 0.389 and -0.061 to -0.271 Gy, respectively. The maximum dose (DMax) of the organ at risk (OAR) structure was 0.082 to 0.327 Gy.
Conclusion: The motion could induce dose discrepancies in tomotherapy dose distribution. The selection of the jaw field width in tomotherapy is crucial for intensity-modulated radiotherapy (IMRT) techniques with moving targets. For larger field widths, the dose discrepancy between the planned and measured doses exhibited an excellent result for gamma index and dose coverage.  

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References

  1. Mackie T R, Holmes T, Swerdloff S, Reckwerdt P, Deasy J O, Yang J, et al. Tomotherapy: a new concept for the delivery of dynamic conformal radiotherapy. Med. Phys. 1993; 20:1709–
  2. Keall PJ, Mageras GS, Balter JM, Emery RS, Forster KM, Jiang SB, et al. The management of respiratory motion in radiation oncology report of AAPM Task Group 76. Med. phys. 2006;33(10):3874-900.
  3. Ezzell GA, Burmeister JW, Dogan N, LoSasso TJ, Mechalakos JG, Mihailidis D, et al. IMRT commissioning: multiple institution planning and dosimetry comparisons, a report from AAPM Task Group 119. Med Phys. 2009;36(11): 5359-73.
  4. Bortfeld T, Jiang SB, Rietzel E. Effects of Motion on the Total Dose Distribution. Seminars in Radiation Oncology. 2004;14(1):41–
  5. Stevens CW, Munden RF, Forster KM, Kelly JF, Liao Z, Starkschall G, et al. Respiratory-Driven Lung Tumor Motion Is Independent Of Tumor Size , Tumor Location , And Pulmonary Function . Int J Radiat Oncol Biol Phys. 2001;51(1): 62–
  6. Plathow C, Ley S, Fink C, Puderbach M, Hosch W, Schmähl A, et al. Analysis of intrathoracic tumor mobility during whole breathing cycle by dynamic MRI. Int J Radiat Oncol Biol Phys. 2004;59(4):952–
  7. Kanagaki B, Read PW, Molloy JA, Larner JM, Sheng K. A motion phantom study on helical Tomotherapy: The dosimetric impacts of delivery technique and motion. Phys Med Biol. 2007;52(1):243–
  8. Yang JN, Mackie TR, Reckwerdt P, Deasy JO, Thomadsen BR. An investigation of Tomotherapy beam delivery. Med Phys. 1997;24(3):425–
  9. Yu CX, Jaffray DA, Wong JW. The effects of intra-fraction organ motion on the delivery of dynamic intensity modulation. Phys Med Biol. 1998;43(1):91–
  10. Kissick M W, Boswell S A, Jeraj R, Mackie T R. Confirmation, refinement, and extension of a study inintrafraction motion interplay with sliding jaw motion. Med. Phys. 2005; 32(7Part1): 2346–
  11. Klein M, Gaede S, Yartsev S. A study of longitudinal tumor motion in helical Tomotherapy using a cylindrical phantom. J Appl Clin Med Phys. 2013;14(2):52–
  12. Park SH, Choi J, Kim J, Ahn S, Kim MJ, Lee H, et al. Impact of the Respiratory Motion and Longitudinal Profile on Helical Tomotherapy. PMP. 2018;29(1):1–
  13. Kim B, Chen J, Kron T, Battista J. Motion-induced dose artifacts in helical Tomotherapy. Phys Med Biol. 2009;54(19):5707–
  14. Langen KM, Papanikolaou N, Balog J, Crilly R, Followill D, Goddu SM, et al. QA for helical Tomotherapy: Report of the AAPM Task Group 148. Medical Physics. 2010;37(9): 4817–
  15. Bedford JL, Lee YK, Wai P, South CP, Warrington AP. Evaluation of the Delta4phantom for IMRT and VMAT verification. Phys. Med. Biol.. 2009;54(9): N167.
  16. Low DA, Moran JM, Dempsey JF, Dong L, Oldham M. Dosimetry tools and techniques for IMRT. Med phys. 20011;38(3): 1313–
  17. Gregoire V. ICRU, Report 83: Prescribing, Recording, and Reporting Photon-Beam Intensity-Modulated Radiation Therapy (IMRT). Journal of the ICRU. 2010;10(1).
  18. Allisy A. ICRU, report 50. Prescribing, Recording, and Reporting Photon-Beam Photon Beam Therapy. ICRU Publ Bethseda MD.1993.
  19. Larsson T. Accuracy of MLC-tracking for inversely optimized arc therapy treatments of varying complexity for two MLCs [dissertasion]. Lund: Lund University. 2010.
  20. Mutaf YD, Scicutella CJ, Michalski D, Fallon K, Brandner ED, Bednarz G, et al. A Simulation Study of Irregular Respiratory Motion and its Dosimetric Impact on Lung Tumors. Phys. Med. Biol. 2011;56(3): 845-59.
  21. Chaudhari SR, Goddu SM, Rangaraj D, Pechenaya OL, Lu W, Kintzel E, et al. Dosimetric variances anticipated from breathing-induced tumor motion during Tomotherapy treatment delivery. Phys. Med. Biol. 2009;54(8): 2541–
Iranian Journal of Medical Physics
Volume 18, Issue 5
September and October 2021
Pages 331-338

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History

  • Receive Date: 08 April 2020
  • Revise Date: 17 July 2020
  • Accept Date: 06 August 2020

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