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Medical Physics / Volume 38 / Issue 12 / RADIATION BIOLOGY

Med. Phys. 38, 6553 (2011); http://dx.doi.org/10.1118/1.3656053 (8 pages)

Use of radiation protraction to escalate biologically effective dose to the treatment target

V. Y. Kuperman

Department of Radiation Oncology, Halifax Health, Daytona Beach, Florida 32114

G. S. Spradlin

Department of Mathematics, Embry-Riddle University, Daytona Beach, Florida 32114

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(Received 12 May 2011; accepted 6 October 2011; revised 4 October 2011; published online 21 November 2011)

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Purpose: The aim of this study is to evaluate how simultaneously increasing fraction time and dose per fraction affect biologically effective dose for the target (BEDtar) while biologically effective dose for the normal tissue (BEDnt) is fixed.
Methods: In this investigation, BEDtar and BEDnt were studied by assuming mono-exponential repair of sublethal damage with tissue dependent repair half-time.
Results: Our results demonstrate that under certain conditions simultaneously increasing fraction time and dose per fraction result in increased BEDtar while BEDnt is fixed. The dependence of biologically effective dose on fraction time is influenced by the dose rate. In this investigation we analytically determined time-varying dose rate math which minimizes BED. Changes in BED with fraction time were compared for constant dose rate and for math.
Conclusions: A number of recent experimental and theoretical studies have demonstrated that slow delivery of radiation (known as radiation protraction) leads to reduced therapeutic effect because of increased repair of sublethal damage. In contrast, our analysis shows that under certain conditions simultaneously increasing fraction time and dose per fraction are radiobiologically advantageous.

© 2011 American Association of Physicists in Medicine

Article Outline

  1. INTRODUCTION
  2. METHODS
    1. LQ model
    2. Dependence of biologically effective dose on fraction time
    3. Dose rate which minimizes protraction factor under the condition of fixed dose per fraction
    4. Gmin in the case of large Rmax
    5. Protraction factor in the case of discrete radiation beams
  3. RESULTS
  4. DISCUSSION
  5. CONCLUSIONS
Digital Object Identifier
http://dx.doi.org/10.1118/1.3656053

KEYWORDS and PACS

Keywords

biological tissues, dosimetry, radiation therapy, biologically effective dose, radiation protraction, sublethal damage repair

PACS

  • 87.55.-x

    Treatment strategy

  • 87.53.Bn

    Dosimetry/exposure assessment

  • 87.53.Jw

    Therapeutic applications, including brachytherapy

PUBLICATION DATA

ISSN

0094-2405 (print)  

Publisher

$abstract.society.value is a Member of CrossRef American Association of Physicists in Medicine

  1. R. G. Dale, “The application of the linear-quadratic dose-effect equation to fractionated and protracted radiotherapy,” Br. J. Radiol. 58, 515–528 (1985). [MEDLINE]
  2. D. J. Brenner, E. J. Hall, Y. Huang, and R. K. Sachs, “Optimizing the time course of brachytherapy and other accelerated radiotherapeutic regimens,” Int. J. Radiat. Oncol., Biol., Phys. 29, 893–901 (1994). [MEDLINE]
  3. J. F. Fowler, J. S. Welsh, and S. P. Howard, “Loss of biological effect in prolonged fraction delivery,” Int. J. Radiat. Oncol, Biol., Phys. 59, 242–249 (2004). [MEDLINE]
  4. H. D. Thames, “An `incomplete-repair' model for survival after fractionated and continuous irradiations,” Int. J. Radiat. Biol. 47, 319–339 (1985). [MEDLINE]
  5. S. H. Benedict, P. S. Lin, R. D. Zwicker, D. T. Huang, and R. K. A. Schmidt-Ullrich, “The biological effectiveness of intermittent irradiation as a function of overall treatment time: Development of correction factors for linac-based stereotactic radio surgery,” Int. J. Radiat. Oncol., Biol., Phys. 37, 765–769 (1997). [MEDLINE]
  6. J. Z. Wang, X. A. Li, W. D. D'Souza, and R. D. Stewart, “Impact of prolonged fraction delivery times on tumor control: a note on caution for intensity-modulated radiation therapy (IMRT),” Int. J. Radiat. Oncol., Biol., Phys. 57, 543–552 (2003). [ISI] [MEDLINE]
  7. Y Shibamoto, M. Ito, C. Suge, H. Ogino, and M. Hara, “Recovery from sublethal damage during intermittent exposure in cultured tumors cells: Implications for dose modifications in radiosurgery and IMRT,” Int. J. Radiat. Oncol., Biol., Phys. 59, 1484–1490 (2004). [MEDLINE]
  8. H Ogino, Y. Shibamoto, C. Sugie, and M. Ito, “Biological effects of intermittent radiation in cultured tumor cells: Influence of fraction number and dose per fraction,” J. Radiat. Res. 46, 401–406 (2005). [MEDLINE]
  9. M. B. Altman, S. J. Chmura, J. O. Deasy, and J. C. Roeske, “Optimization of the temporal pattern of radiation: an IMRT based study,” Int. J. Radiat. Oncol., Biol., Phys. 66 898–905 (2006). [Inspec] [MEDLINE]
  10. V. Moiseenko, C. Duzenli, and R. E. Durand, “In vitro study of cell survival following dynamic MLC intensity-modulated radiation therapy dose delivery,” Med. Phys. 34, 1514–1520 (2007)MPHYA6000034000004001514000001. [MEDLINE]
  11. J. M. Bewes, N. S. Suchowerska, M. Jackson, M. Zhang, and D. R. McKenzie, “The radiobiological effect of intra-fraction dose-rate modulation in intensity modulated radiation therapy (IMRT),” Phys. Med. Biol. 53, 3567–3578 (2008).
  12. V. Y. Kuperman, A. M. Ventura, and M. Sommerfeldt, “Effect of radiation protraction in intensity-modulated radiation therapy with direct aperture optimization: A phantom study,” Phys Med Biol 53, 3279–3292 (2008). [MEDLINE]
  13. M. B. Altman, M. A. Stinauer, D. Javier, B. D. Smith, L. C. Herman, M. L. Pytynia, B. Aydogan, C. A. Pelizzari, S. J. Chmura, and J. C. Roeske, “Validation of temporal optimization effects for a single fraction of radiation in vitro,” Int. J. Radiat. Oncol., Biol., Phys. 75, 1240–1246 (2009).
  14. D. J. Brenner and E. J. Hall, “Conditions for the equivalence of continuous and pulsed low dose rate brachytherapy,” Int. J. Radiat. Oncol., Biol. Phys. 20, 181–190 (1991). [Inspec] [ISI] [MEDLINE]
  15. D. E. Lea and D. G. Catcheside, “The mechanism of the induction by radiation of chromosome aberrations in tradescantia,” J. Genet. 44, 216–245 (1942).
  16. G. W. Barendsen, “Dose fractionation, dose rate and iso-effect relationships for normal tissue responses,” Int. J. Radiat. Oncol., Biol., Phys. 8, 1981–1997 (1982). [MEDLINE]
  17. J. F. Fowler, “The linear-quadratic formula and progress in fractionated radiotherapy,” Br J Radiol 62, 679–694 (1989). [Inspec] [ISI] [MEDLINE]
  18. M. C. Joiner, B. Marples, P. Lambin, S. C. Short, and I. Turesson, “Low-dose hypersensitivity: current status and possible mechanisms,” Int. J. Radiat. Oncol., Biol., Phys. 49, 379–389 (2001). [MEDLINE]
  19. M. Guerrero and X. A. Li, “Extending the linear–quadratic model for large fraction doses pertinent to stereotactic radiotherapy,” Phys. Med. Biol. 49, 4825–4835 (2004). [Inspec] [MEDLINE]
  20. J. P. Kirkpatrick, J. J. Meyer, and L. B. Marks, “The L-Q model is inappropriate to model high-dose per fraction effects,” Semin. Radiat. Oncol. 18 240–243 (2008). [MEDLINE]
  21. L. G. Smith, R. C. Miller, N. Richards, D. J. Brenner, and E. J. Hall, “Investigation of hypersensitivity to fractionated low-dose radiation exposure,” Int. J. Radiat. Oncol., Biol., Phys. 45, 187–191 (1999).
  22. D. J. Brenner, “The linear-quadratic model is an appropriate methodology for determining isoeffective doses at large doses per fraction,” Semin. Radiat. Oncol. 18, 234–239 (2008). [MEDLINE]

Figures (click on thumbnails to view enlargements)

FIG.1
math as a function of time.

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FIG.2
Comparison between G0 from Eq. ( 3 ) and Gmin from Eq. ( 22 ): (1) G0, (2) Gmin and (3) (1 − Gmin/G0).

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FIG.3
(a) Equally weighted, equidistant beams approximate the effect of constant dose rate [see Eq. ( 3 )]. (b) A train of nonequally weighted beams which minimize protraction factor. Note that the first and last beams in (b) deliver dose d1 = d/(2+μT). These beams are separated by N equally weighted beams each delivering dose d2,N = μTdN-1/(2+μT).

FIG.3 Download High Resolution Image (.zip file) | Export Figure to PowerPoint

FIG.4
Protraction factor G in the case of equally weighted, equidistant beams: (1) two beams; (2) three beams; (3) ten beams; and (4) G0 described by Eq. ( 3 )

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FIG.5
Percent change in biologically effective dose (δBED) as a function of fraction time: 1(a) and 1(b) depict δBEDtar while BEDnt is fixed; 2(a) and 2(b) show δBEDnt while BEDtar is fixed. Solid curves represent the effect of constant dose rate; dashed curves correspond to variable dose rate math. Other parameters: dtar,0 = 2 Gy; dnt,0 = 1.5 Gy; T1/2,tar = T1/2,nt = 30 min.

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FIG.6
TCP and NTCP versus fraction time: 1(a) and 1(b)—TCP for fixed BEDnt; 2(a) and 2(b)—NTCP for fixed BEDtar. Solid curves and dashed curves correspond to constant dose rate and variable dose rate math, respectively. The radiobiological parameters are the same as in Fig. 5.

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