Skip to main content

Advertisement

SpringerLink
Log in

Image quality and dose distributions of three linac-based imaging modalities

Bildqualität und Dosisverteilungen dreier Linac-basierter Bildgebungssysteme

  • Original Article
  • Published:
Strahlentherapie und Onkologie Aims and scope Submit manuscript

Abstract

Background and purpose

Linac-based patient imaging is possible with a variety of techniques using different photon energies. The purpose of this work is to compare three imaging systems operating at 6 MV, flattening free filter (FFF) 1 MV, and 121 kV.

Patients and methods

The dose distributions of all pretreatment set-up images (over 1,000) were retrospectively calculated on the planning computed tomography (CT) images for all patients with prostate and head-and-neck cancer treated at our institution in 2013. We analyzed the dose distribution and the dose to organs at risk.

Results

For head-and-neck cancer patients, the imaging dose from 6-MV cone beam CT (CBCT) reached maximum values at around 8 cGy. The 1-MV CBCT dose was about 63–79 % of the 6-MV CBCT dose for all organs at risk. Planar imaging reduced the imaging dose from CBCT to 30–40 % for both megavoltage modalities. The dose from the kilovoltage CBCT was 4–10 % of the 6-MV CBCT dose. For prostate cancer patients, the maximum dose from 6-MV CBCT reached 13–15 cGy, and was reduced to 66–73 % for 1 MV. Planar imaging reduces the MV CBCT dose to 10–20 %. The kV CBCT dose is 15–20 % of the 6-MV CBCT dose, slightly higher than the dose from MV axes. The dose distributions differ markedly in response to the different beam profiles and dose–depth characteristics.

Zusammenfassung

Hintergrund und Ziel

Linac-basierte Bildgebung zur Patientenlagerung ist mit einer Vielzahl von Techniken unterschiedlicher Photonenenergien möglich. Ziel dieser Arbeit ist der Vergleich dreier Bildgebungssysteme mit 6 MV (Megavolt), FFF 1 MV, und 121 kV (Kilovolt).

Patienten und Methoden

Für alle im Jahr 2013 an unserer Klinik behandelten Prostata- und HNO-Patienten wurden retrospektiv die Dosisverteilungen aller Verifikationsaufnahmen (über 1000 insgesamt) auf der Planungs-Computertomographie (CT) berechnet. Wir analysierten die Dosisverteilung und die Dosis an den Risikoorganen.

Ergebnisse

Bei HNO-Patienten erreichte die Dosis von 6 MV „Cone-beam“-CT (CBCT)Maximalwerte um 8 cGy. Mit 1 MV wird die Dosis auf 63–79 % des 6 MV-Werts reduziert. Planare Bildgebung reduzierte die Bildgebungsdosis von CBCT für beide MV-Bildgebungen auf 30–40 %. Die Dosis von kV-CBCT betrug etwa 4–10 % der Dosis von 6 MV CBCT. Für Prostatapatienten erreichte die Bildgebungsdosis von 6 MV CBCT-Werte von 13–15 cGy, was durch Anwendung der 1-MV-Energie auf 66–73 % reduziert wurde. Planare Bildgebung reduzierte diesen Wert auf 10–20 %. Die Dosis von kV-CBCT lag bei 15–20 % der 6-MV-CBCT-Dosis, etwas höher als die Dosis von MV-Achsen. Die Dosisverteilungen unterschieden sich aufgrund der verschiedenen Strahlprofile und Tiefendosiskurven.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6

Similar content being viewed by others

References

  1. Akino Y, Koizumi M, Sumida I, Takahashi Y, Ogata T, Ota S, Isohashi F, Konishi K, Yoshioka Y (2012) Megavoltage cone beam computed tomography dose and the necessity of reoptimization for imaging dose-integrated intensity-modulated radiotherapy for prostate cancer. Int J Radiat Oncol Biol Phys 82:1715–1722

    Article  PubMed  Google Scholar 

  2. Alaei P, Spezi E (2012) Commissioning kilovoltage cone-beam CT beams in a radiation therapy treatment planning system. J App Clin Med Phys 13:19–33

    Google Scholar 

  3. Alaei P, Ding G, Guan H (2012) Inclusion of the dose from kilovoltage cone beam CT in the radiation therapy treatment plans. Med Phys 37:244–248

    Article  Google Scholar 

  4. Amer A, Marchant T, Sykes J, Czajka J, Moore C (2007) Imaging doses from the Elekta Synergy X-ray cone beam CT system. Brit J Radiol 80:476–482

    Article  CAS  PubMed  Google Scholar 

  5. Beltran Ch, Lukose R, Gangadharan B, Bani-Hashemi A, Faddegon BA (2009) Image quality & dosimetric property of an investigational imaging beam line MV-CBCT. J App Clin Med Phys 10:3023

    Google Scholar 

  6. Breitbach EK, Maltz JS, Gangadharan B, Ban-Hashemi A, Anderson CM, Bhatia SK, Stiles J, Edwards DS, Flynn RT (2011) Image quality improvement in megavoltage cone beam CT using an imaging beam line and sintered pixelated array systems. Med Phys 38:5969–5979

    Article  PubMed  Google Scholar 

  7. Chan MF, Yang J, Song Y, Burman C, Chan P, Li S (2011) Evaluation of imaging performance of major image guidance systems. Biomed Imaging Interv J 7:e11

    PubMed Central  PubMed  Google Scholar 

  8. Ding GX, Coffey ChW (2009) Radiation dose from kilovoltage cone-beam computed tomography in an image-guided radiotherapy procedure. Int J Radiat Oncol Biol Phys 73:610–617

    Article  PubMed  Google Scholar 

  9. Ding GX, Munro P, Pawlowski J, Malcolm A, Coffey ChW (2010) Reducing radiation exposure to patients from kV-CBCT imaging. Radiother Oncol 97:585–592

    Article  PubMed  Google Scholar 

  10. Dzierma Y, Nuesken FG, Licht NP, Rübe CH (2013) Dosimetric properties and commissioning of cone-beam CT image beam line with a carbon target. Strahlenther Onkol 189:566–572

    Article  CAS  PubMed  Google Scholar 

  11. Dzierma Y, Nuesken F, Otto W, Alaei P, Licht N, Rübe CH (2014) Dosimetry of an in-line kilovoltage imaging system and implementation in treatment planning. Int J Radiat Oncol Biol Phys 88:913–919

    Article  PubMed  Google Scholar 

  12. Faddegon BA, Wu V, Pouliot J, Gangadharan B, Bani-Hashemi A (2008) Low dose megavoltage cone beam computed tomography with an unflattened 4 MV beam from a carbon target. Med Phys 35:5777–5786

    Article  PubMed  Google Scholar 

  13. Faddegon BA, Alubin M, Bani-Hashemi A, Gangadharan B, Gottschalk AR, Morin O, Sawkey D, Wu V, Yom SS (2010) Comparison of patient megavoltage cone beam CT images acquired with an unflattened beam from a carbon target and a flattened treatment beam. Med Phys 37:1737–1741

    Article  PubMed  Google Scholar 

  14. Fast MF, Krauss A, Oelfke U, Nill S (2012a) Position detection accuracy of a novel linac-mounted intrafractional x-ray imaging system. Med Phys 39:109–118

    Article  PubMed  Google Scholar 

  15. Fast MF, Koenig T, Oelfke U, Nill S (2012b) Performance characteristics of a novel megavoltage cone-beam-computed tomography device. Phys Med Biol 57:N15–N24

    Article  CAS  PubMed  Google Scholar 

  16. Gayou O, Parda DS, Johnson M, Miften M (2007) Patient dose and image quality from mega-voltage cone beam computed tomography imaging. Med Phys 34:499–506

    Article  CAS  PubMed  Google Scholar 

  17. Islam MK, Purdie THG, Norrlinger BD, Alasti H, Moseley DJ, Sharpe MB, Siewerdsen JH, Jaffray DA (2006) Patient dose from kilovoltage cone beam computed tomography imaging in radiation therapy. Med Phys 33:1573–1582

    Article  PubMed  Google Scholar 

  18. Jaffray DA, Drake DG, Moreau M, Martinez AA, Wong JW (1999) A radiographic and tomographic imaging system integrated into a medical linear accelerator for localization of bone and soft-tissue targets. Int J Radiat Oncol Biol Phys 45:773–789

    Article  CAS  PubMed  Google Scholar 

  19. Jaffray DA, Siewerdsen JH, Wong JW, Martinez AA (2002) Flat-panel cone-beam computed tomography for image-guided radiation therapy. Int J Radiat Oncol Biol Phys 53:1337–1349

    Article  PubMed  Google Scholar 

  20. Miften M, Gayou O, Reitz B, Fuhrer R, Leicher B, Parda DS (2007) IMRT planning and delivery incorporating daily dose from mega-voltage cone-beam computed tomography imaging. Med Phys 34:3760–3767

    Article  PubMed  Google Scholar 

  21. Morin O, Gillis A, Chen J, Aubin M, Bucci MK, Roach III M, Pouliot J (2006) Megavoltage cone-beam CT: system description and clinical applications. Med Dosim 31:51–61

    Article  PubMed  Google Scholar 

  22. Morin O, Gillis A, Descovich M, Chen J, Aubin M, Aubry J-F, Chen H, Gottschalk AG, Xia P, Pouliot J (2007) Patient dose considerations for routine megavoltage cone-beam CT imaging. Med Phys 34:1819–1827

    Article  PubMed  Google Scholar 

  23. Ostapiak OZ, O’Brien PF, Faddegon BA (1998) Megavoltage imaging with low Z targets: implementation and characterization of an investigational system. Med Phys 25:1910–1918

    Article  CAS  PubMed  Google Scholar 

  24. Pouliot J, Bani-Hashemi A, Chen J et al (2005) Low-dose megavoltage cone-beam CT for radiation therapy. Int J Radiat Oncol Biol Phys 61:552–560

    Article  PubMed  Google Scholar 

  25. Robar JL, Connell T, Huang W, Kelly RG (2009) Megavoltage planar and cone-beam imaging with low-Z targets: dependence of image quality improvement on beam energy and patient separation. Med Phys 36:3955–3963

    Article  PubMed  Google Scholar 

  26. Schiller K, Petrucci A, Geinitz H, Schuster T, Specht H, Kampfer S, Duma MN (2014) Impact of different setup approaches in image-guided radiotherapy as primary treatment for prostate cancer. Strahlenther Onkol 190:722–726

    Article  PubMed  Google Scholar 

  27. Song WY, Kamath S, Ozawa S, Ani SA, Chvetsov A, Bhandare N, Palta JR, Liu C, Li JG (2008) A dose comparison study between XVI and OBI CBCT systems. Med Phys 35:480–486

    Article  PubMed  Google Scholar 

  28. Spezi E, Downes P, Jarvis R, Radu E, Staffurth J (2012) Patient-Specific three-dimensional concomitant dose from cone beam computed tomography exposure in image-guided radiotherapy. Int J Radiat Oncol Biol Phys 83:419–426

    Article  PubMed  Google Scholar 

  29. Stützel J, Oelfke U, Nill S (2008) A quantitative image quality comparison of four different image guided radiotherapy devices. Radiother Oncol 86:20–24

    Article  PubMed  Google Scholar 

  30. Van Herk M (2007) Different styles of image-guided radiotherapy. Semin Radiat Oncol 17:258–267

    Article  PubMed  Google Scholar 

  31. Zhang Y, Yan Y, Nath R, Bao SH, Deng J (2012) Personalized assessment of kV cone beam computed tomography doses in image-guided radiotherapy of pediatric cancer patients. Int J Radiat Oncol Biol Phys 83:1649–1654

    Article  PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Klinik für Strahlentherapie und Radioonkologie, Universitätsklinikum des Saarlandes, Kirrberger Straße Geb. 6.5, 66421, Homburg/Saar, Deutschland

    Yvonne Dzierma, Evemarie Ames,  Frank Nuesken,  Jan Palm,  Norbert Licht &  Christian Rübe

Authors
  1. Yvonne Dzierma
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Evemarie Ames
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Frank Nuesken
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Jan Palm
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Norbert Licht
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Christian Rübe
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Yvonne Dzierma.

Ethics declarations

Conflict of interest

Y. Dzierma, E. Ames, F. Nuesken, J. Palm, N. Licht, and C. Rübe state that there are no conflicts of interest.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Dzierma, Y., Ames, E., Nuesken, F. et al. Image quality and dose distributions of three linac-based imaging modalities. Strahlenther Onkol 191, 365–374 (2015). https://doi.org/10.1007/s00066-014-0798-7

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00066-014-0798-7

Keywords

Schlüsselwörter

Search

Navigation