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. 2017 Apr 6;22(2):103–110. doi: 10.1016/j.rpor.2017.02.006

SBRT planning for liver metastases: A focus on immobilization, motion management and planning imaging techniques

Olivier Riou a,⁎, Carmen Llacer Moscardo a, Pascal Fenoglietto a, Emmanuel Deshayes a, Raphaël Tetreau a, Jessica Molinier a, Alexis Lenglet a, Eric Assenat a,b, Marc Ychou a,b, Boris Guiu b, Norbert Aillères a, Ludovic Bedos a, David Azria a
PMCID: PMC5411892  PMID: 28490980

Abstract

Aim

To evaluate the different techniques used for liver metastases Stereotactic Body Radiation Therapy (SBRT) planning. We especially focused on immobilization devices, motion management and imaging used for contouring.

Background

Although some guidelines exist, there is no consensus regarding the minimal requirements for liver SBRT treatments.

Materials and methods

We reviewed the main liver metastases SBRT publications and guidelines; and compared the techniques used for immobilization, motion management, margins and imaging.

Results

There is a wide variety of techniques used for immobilization, motion management and planning imaging.

Conclusions

We provide a subjective critical analysis of minimal requirements and ideal technique for liver SBRT planning.

Keywords: Liver metastases, SBRT, Planning, Immobilization, Motion management, Contouring

1. Background

SBRT is an attractive option of local treatment for patients with liver metastases.1, 2, 3, 4, 5 Liver SBRT relies on the same principle as intracranial stereotactic treatments, which are high dose per fraction, few fractions, high biological equivalent dose and very high precision. On the opposite, some differences are target volumes (usually much bigger) and the necessary motion management because liver tumors are moving targets.6, 7, 8, 9

Despite a rapid development of the technique and a wide variety of tools available, there is a lack of consensus regarding those useful and/or necessary for planning. Especially, there is a wide heterogeneity regarding set up, dose prescription and contouring, although some guidelines are available.10, 11, 12

Based on the published results, we will critically discuss in this paper the minimal requirements for liver mets SBRT planning.

All aspects regarding quality insurance and specific dosimetric considerations will not be the subject of this review.

2. Machine type and dose prescription

Most of the published studies reported treatments performed on linear accelerator (see Table 1).13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 Some other reported treatments on Cyberknife®26, 27, 28, 29 or other machines dedicated for SBRT treatments.30, 31

Table 1.

Overview of the main published studies of SBRT for liver mets and the corresponding techniques used for immobilization, motion management and planning imaging.

Authors Year Patients number Lesions/patient RT technique Dose Fractions PTV definition RT planning technique PET/CT fusion MRI fusion Contention Fiducials Motion management
Ambrosino 2009 27 N/A Cyberknife 25–60 3 Tumor = GTV = CTV CT scan with contrast Yes No N/A Yes Synchrony® system
PTV = CTV + 5 mm (10 mm Cr-Ca)
PTV → 80% isodose



Andratschke 2015 74 1–4 Linac 30–35 3–5 Tumor = GTV = CTV CT scan with contrast Yes Yes Vacuum couch No Free breathing
3D-CRT PTV = CTV + 5 mm (10 mm Cr-Ca) Sequential CTs Oxygen Abdominal compression
“Composite” ITV (2009) 4D PET CT (2009) 4D PET CT (2009)
PTV = “composite” ITV + 5 mm (2009) 4D CT (2009) 4D CT (2009)



Dawson 2006 34 N/A Linac 24–57 (phase I–II) 6 Tumor = GTV CT scan with contrast No Yes Customized immobilization No Breath-hold
3D-CRT CTV = GTV + 8 mm MRI simulation Active breathing control
PTV = CTV + 5 mm 4D CT if not possible (free breathing)



Goodman 2010 19 N/A Cyberknife 18–30 1 Tumor = GTV = CTV CT scan with contrast Yes No Alpha Cradle Yes (3–5) Synchrony® system
PTV = CTV + 5–10 mm 4D CT 4D CT



Herfarth 2001 37 1–4 Linac 14–26 1 Tumor = GTV = CTV CT scan with contrast No No Vacuum couch No Free breathing
3D-CRT PTV = CTV + 6 mm (10 mm Cr-Ca) Abdominal compression
PTV → 80% isodose



Hoyer 2006 44 1–5 Linac 45 3 Tumor = CTV CT scan with contrast No No Stereotactic body frame (Aahrus) No Free breathing
3D-CRT PTV = CTV + 5 mm (10 mm Cr-Ca) Custom-made vacuum pillow (Copenhagen)
CTV → 95% isodose
PTV → 67% isodose



Katz 2007 69 1–6 Novalis ExacTrac 30–55 10 Tumor = GTV = CTV CT scan with contrast Yes Yes Vacuum cushion No External body fiducial markers
PTV = CTV + 7 mm (10 mm Cr-Ca) Relaxed end-expiratory breath holds ExacTrac®
PTV → 80% isodose Respiratory gating



Kavanagh 2006 36 (21 evaluable) 1–3 Linac 60 3 Tumor = GTV CT scan with contrast Yes Yes Body frame with reference fiducial markers or No Breath-holding or
3D-CRT PTV = GTV + 5–10 mm Equivalent customized external vacuum-type or abdominal compression
PTV → 80–90% isodose Synthetic body mold



Lee 2009 68 1–8 Linac 27.7–60 (phase I) 6 Tumor = GTV CT scan with contrast No No Customized body mold No Active breathing control or
3D-CRT CTV = GTV + 8 mm MRI with contrast abdominal compression
PTV = CTV + 5 mm minimum



Llacer Moscardo 2016 41 1–10 Novalis TrueBeam STX 40–50 Gy 5–10 “Composite” ITV CT scan with contrast Yes Yes Custom-made posterior pillow (mold care) If no surgical clips Adaptive gating
VMAT PTV = “composite” ITV + 5 mm MRI simulation 4D PET CT
4D PET CT 4D CT
4D CT



Mendez Romero 2006 17 1–4 Linac 30 or 37.5 3 Tumor = CTV CT scan with contrast No No Stereotactic body frame Yes Abdominal compression
3D-CRT PTV = CTV + 5–10 mm Gold fiducials
PTV → 65% isodose



Rusthoven 2009 47 1–3 Linac 36–60 (phase I/II) 3 Tumor = GTV CT scan with contrast Yes Yes External vacuum-type or No Active breathing control or
3D-CRT or conformal arcs PTV = GTV + 7–15 mm synthetic body mold Abdominal compression or
PTV → 80–90% isodose Free breathing
External body fiducial markers



Schefter 2005 18 1–3 Linac 36–60 (phase I) 3 Tumor = GTV = CTV CT scan with contrast Yes Yes Stereotactic body frame or No Active breathing control or
3D-CRT or conformal arcs PTV = CTV + 5 mm (10 mm Cr-Ca) equivalent customized external vacuum-type or Abdominal compression or
PTV → 80–90% isodose synthetic body mold External body fiducial markers



Scorsetti 2013 61 1–3 Linac 75 3 Tumor = GTV = CTV CT scan with contrast Yes Yes Thermoplastic body mask No Abdominal compression
VMAT PTV = CTV + 4–6 mm (7–10 mm Cr-Ca) 4DCT (30%) Stereotactic body frame 4DCT (30%)



Stintzing 2010 14 1–2 Cyberknife 24 1 Tumor = GTV CT scan with contrast No No N/A Yes Synchrony® system
PTV = GTV + 7 mm MRI with contrast Gold fiducials
PTV → 70% isodose



Van de Voorde 2015 33 1–3 Linac 5–20 per fraction 3–10 Tumor = GTV 4D PET CT with contrast Yes Yes Knee and feet support No 4D PET CT
VMAT or IMRT PTV = GTV + 10 mm CT scan or MRI if performed Breast board bilateral arm support



Vautravers 2011 42 1–4 Cyberknife 40–45 3–4 Tumor = GTV CT scan with contrast No Yes N/A Yes Synchrony® system
CTV = GTV + 5 mm Gold fiducials
PTV = CTV + 3 mm



Wulf 2006 39 1–3 Linac 26–37.5 1–4 Tumor = GTV CT scan with contrast Yes Yes Stereotactic body frame No Abdominal compression
3D-CRT CTV = GTV + 3 mm
PTV = CTV + 5 mm (5–10 mm Cr-Ca)
PTV → 65–80% isodose
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There is a large heterogeneity in dose prescription and fractionation used. Number of fractions varied from 1 to 10, and dose prescription from 14 to 75 Gy. Most treatments were tridimensional conformal radiotherapy, performed with multiple coplanar beams,13, 14, 15, 16, 17, 18, 19, 24, 25 but some used non coplanar beams20, 21, 30 or volumetric modulated arctherapy.22, 23, 31 Dose prescription varied also depending on the type of treatment: isocentric (prescription to an isodose line) vs. volumetric.

3. Immobilization and set up

As SBRT aims at delivering high biological equivalent dose to targets in close proximity to organs at risk, the use of a reproducible immobilization system enhances the security of the treatments and enables to decrease planning target volume margins.

There are basically 3 contention types used for liver SBRT: generic contentions, not different from the ones in use for conventional radiotherapy23; personalized noninvasive contentions, such as posterior vacuum based or Mold care contentions31; and stereotactic dedicated contentions, usually vacuum based “whole body”.22, 25 The first ones might be less accurate and reproducible; while the last ones might be more difficult to use and might reduce patient tolerance to the treatment, especially if long fractions are expected. Customized immobilization devices are highly recommended to minimize intrafractional motion due to patient movement. Image guidance should be adapted to the type of immobilization used for treatment.32

4. Respiratory management

Motion management is a major challenge in abdominal SBRT.

There are 5 strategies for motion management in this setting, as described by Wolthaus et al.33

The first one is to treat patients in free breathing, but without specific knowledge of the respiratory motion, with margins taking into account the respiratory movement of the target. This results in large irradiated volumes, as margins have to be adapted to largely encompass this motion without really knowing it. The second is to treat on Internal Target Volume (ITV), which is the tumor volume on all respiratory phases plus additional set-up margins. This strategy requires an evaluation of tumor motion and its reproducibility over time by different means (4D CT, 4D PET CT, inhale and exhale phase's acquisitions, etc.). The third one is to achieve a reduction in the ITV by respiratory blockage or abdominal compression. Abdominal compression is widely used in liver SBRT.13, 15, 17, 18, 19, 20, 21, 22, 24, 25 Another way to reduce ITV is to identify all respiratory phases like in ITV basis treatment, but to choose the phases for treatment, either the most reproducible or the ones with the minimal movement. This requires to be able to identify the phases during planning and treatment; and to manage to stop the irradiation outside of these phases. The last strategy is to identify a time weighted average position, to apply margins and to treat on that volume, rather than on the whole ITV. With that strategy, the risk is to miss the target during a minimal time of the respiratory phase, which has to be insignificant in order not to have clinical consequences.

Respiratory management may use a variety of methods, including respiratory gating, tumor tracking, organ motion dampening, or patient-directed methods.12

5. Fiducials implants

Few teams chose to perform fiducial implants, maybe because patients referred for SBRT are usually frail and a complete noninvasive procedure might be more suitable for them.19, 25, 26, 27, 28, 29

Nonetheless, the use of fiducials is a reliable way to evaluate respiratory motion during planning and/or treatment, as liver metastases are usually invisible without contrast injection. If present, surgical clips of previous surgery, bile duct prosthesis or chemotherapy catheters might play the same role as fiducials.31 The use of fiducials (3–5 gold fiducials) seems to be mandatory when using Cyberknife® for liver SBRT.26, 27, 28, 29

6. Imaging for contouring – multimodality imaging

Bi or triphasic CT scan with contrast seems to be mandatory for liver mets SBRT planning. Nearly all published series used PET/CT and/or MRI coregistration in order to improve contouring. Few teams used these last modalities in treatment position, although they might improve contouring.13, 23, 31 Metabolic imaging seems to be of particular interest as MRI and CT scan have been shown to underestimate tumor size in a surgical cohort with radiographic to pathologic correlation.34

The use of four-dimensional computed tomography (4D CT), although not mandatory, helps with tumor motion evaluation in lung and abdominal SBRT.35, 36, 37 It might be more physiologic than the use of end-expiratory and/or end-inspiratory acquisitions to evaluate liver motion. Some concerns remain on whether it may or may not adequately represent daily intrafractional motion of abdominal tumors.38

The use of 4D PET CT in treatment position may better define the respiratory movements of liver targets and improve SBRT planning for liver metastases.39, 40, 41 Furthermore, non respiratory-gated PET exams can both misdiagnose liver metastases and underestimate the real internal target volumes.39

The ideal imaging technique for liver SBRT could thus incorporate triphasic CT Scan, 4D CT, MRI and 4D PET CT, all in treatment position (Fig. 1).

Fig. 1.

Fig. 1

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Coronal view of 4D CT (right side) and 4D PET CT (left side) in end expiratory (upper part) and end inspiratory (lower part) phases in a patient with liver met referred for SBRT. The respiratory cycle of the patient is divided in ten phases acquired for 4D CT and 4D PET CT. The volume is set by contouring each one of the ten phases and overlaps the contours to create an internal target volume. Only the end expiratory and end inspiratory phases of these ten phases are shown.

7. Contouring and margins

Gross tumor volume (GTV) is the tumor volume seen on the planning exams. No additional clinical target volume (CTV) margin is added. An internal target volume (ITV) is created to account for tumor motion if it is evaluated on the planning exams. Breathing-related liver motion may be assessed by four-dimensional CT, cine-magnetic resonance imaging, or two-dimensional kilovoltage (kV) fluoroscopy to determine appropriate planning target volume margins.9

A planning target volume (PTV) margin is then added to encompass set up margins. A 5 mm radial and a 10 mm craniocaudal margin are widely chosen in the published studies on liver metastases SBRT,42, 43, 44, 45 although some teams reported smaller setup errors in this setting.46, 47, 48

Image guidance should be performed before each fraction of treatment and during beam delivery if possible.

All margins should be adapted to the whole technique of treatment used including contentions and their accuracy, motion management for planning and treatment and the precision of image guidance before and during treatment delivery.1

8. Conclusion

SBRT is a complex procedure that requires adapted methods for planning. Many different methods can be used, provided they result in a sufficient level of precision. Multimodality imaging is necessary to improve the accuracy of contouring. Margins should be adapted to the methodology of contouring, respiratory management, contention and set-up reproducibility. Special care should be taken to immobilization, respiratory management and imaging for contouring and guidance.

Conflict of interest

None declared.

Financial disclosure

None declared.

References

  • 1.Comito T., Clerici E., Tozzi A., D’Agostino G. Liver metastases and SBRT: a new paradigm? Rep Pract Oncol Radiother. 2015;20(6):464–471. doi: 10.1016/j.rpor.2014.10.002. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Scorsetti M., Clerici E., Comito T. Stereotactic body radiation therapy for liver metastases. J Gastrointest Oncol. 2014;5(3):190–197. doi: 10.3978/j.issn.2078-6891.2014.039. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Aitken K.L., Hawkins M.A. Stereotactic body radiotherapy for liver metastases. Clin Oncol. 2015;27(5):307–315. doi: 10.1016/j.clon.2015.01.032. [DOI] [PubMed] [Google Scholar]
  • 4.Bourgier C., Azria D., Fenoglietto P. Radiothérapie stéréotaxique extracrânienne et oligométastases. Cancer/Radiothérapie. 2014;18(4):337–341. doi: 10.1016/j.canrad.2014.02.008. [DOI] [PubMed] [Google Scholar]
  • 5.Schefter T.E., Kavanagh B.D. Radiation therapy for liver metastases. Semin Radiat Oncol. 2011;21(4):264–270. doi: 10.1016/j.semradonc.2011.05.006. [DOI] [PubMed] [Google Scholar]
  • 6.Tree A.C., Khoo V.S., Eeles R.A. Stereotactic body radiotherapy for oligometastases. Lancet Oncol. 2013;14(1):e28–e37. doi: 10.1016/S1470-2045(12)70510-7. [DOI] [PubMed] [Google Scholar]
  • 7.Almaghrabi M.Y., Supiot S., Paris F., Mahé M.-A., Rio E. Stereotactic body radiation therapy for abdominal oligometastases: a biological and clinical review. Radiat Oncol Lond Engl. 2012;7:126. doi: 10.1186/1748-717X-7-126. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 8.Alongi F., Arcangeli S., Filippi A.R., Ricardi U., Scorsetti M. Review and uses of stereotactic body radiation therapy for oligometastases. Oncologist. 2012;17(8):1100–1107. doi: 10.1634/theoncologist.2012-0092. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9.Høyer M., Swaminath A., Bydder S. Radiotherapy for liver metastases: a review of evidence. Int J Radiat Oncol. 2012;82(3):1047–1057. doi: 10.1016/j.ijrobp.2011.07.020. [DOI] [PubMed] [Google Scholar]
  • 10.Benedict S.H., Yenice K.M., Followill D. Stereotactic body radiation therapy: the report of AAPM Task Group 101. Med Phys. 2010;37(8):4078–4101. doi: 10.1118/1.3438081. [DOI] [PubMed] [Google Scholar]
  • 11.Sahgal A., Roberge D., Schellenberg D. The Canadian Association of Radiation Oncology scope of practice guidelines for lung, liver and spine stereotactic body radiotherapy. Clin Oncol R Coll Radiol G B. 2012;24(9):629–639. doi: 10.1016/j.clon.2012.04.006. [DOI] [PubMed] [Google Scholar]
  • 12.Potters L., Kavanagh B., Galvin J.M. American Society for Therapeutic Radiology and Oncology (ASTRO) and American College of Radiology (ACR) practice guideline for the performance of stereotactic body radiation therapy. Int J Radiat Oncol Biol Phys. 2010;76(2):326–332. doi: 10.1016/j.ijrobp.2009.09.042. [DOI] [PubMed] [Google Scholar]
  • 13.Andratschke N.H., Nieder C., Heppt F., Molls M., Zimmermann F. Stereotactic radiation therapy for liver metastases: factors affecting local control and survival. Radiat Oncol Lond Engl. 2015;10:69. doi: 10.1186/s13014-015-0369-9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Dawson L.A., Eccles C., Craig T. Individualized image guided iso-NTCP based liver cancer SBRT. Acta Oncol. 2006;45(7):856–864. doi: 10.1080/02841860600936369. [DOI] [PubMed] [Google Scholar]
  • 15.Herfarth K.K., Debus J., Lohr F. Stereotactic single-dose radiation therapy of liver tumors: results of a phase I/II trial. J Clin Oncol Off J Am Soc Clin Oncol. 2001;19(1):164–170. doi: 10.1200/JCO.2001.19.1.164. [DOI] [PubMed] [Google Scholar]
  • 16.Hoyer M., Roed H., Traberg Hansen A. Phase II study on stereotactic body radiotherapy of colorectal metastases. Acta Oncol Stockh Swed. 2006;45(7):823–830. doi: 10.1080/02841860600904854. [DOI] [PubMed] [Google Scholar]
  • 17.Kavanagh B.D., Schefter T.E., Cardenes H.R. Interim analysis of a prospective phase I/II trial of SBRT for liver metastases. Acta Oncol Stockh Swed. 2006;45(7):848–855. doi: 10.1080/02841860600904870. [DOI] [PubMed] [Google Scholar]
  • 18.Lee M.T., Kim J.J., Dinniwell R. Phase I study of individualized stereotactic body radiotherapy of liver metastases. J Clin Oncol Off J Am Soc Clin Oncol. 2009;27(10):1585–1591. doi: 10.1200/JCO.2008.20.0600. [DOI] [PubMed] [Google Scholar]
  • 19.Méndez Romero A., Wunderink W., Hussain S.M. Stereotactic body radiation therapy for primary and metastatic liver tumors: a single institution phase I–II study. Acta Oncol Stockh Swed. 2006;45(7):831–837. doi: 10.1080/02841860600897934. [DOI] [PubMed] [Google Scholar]
  • 20.Rusthoven K.E., Kavanagh B.D., Cardenes H. Multi-institutional phase I/II trial of stereotactic body radiation therapy for liver metastases. J Clin Oncol Off J Am Soc Clin Oncol. 2009;27(10):1572–1578. doi: 10.1200/JCO.2008.19.6329. [DOI] [PubMed] [Google Scholar]
  • 21.Schefter T.E., Kavanagh B.D., Timmerman R.D., Cardenes H.R., Baron A., Gaspar L.E. A phase I trial of stereotactic body radiation therapy (SBRT) for liver metastases. Int J Radiat Oncol Biol Phys. 2005;62(5):1371–1378. doi: 10.1016/j.ijrobp.2005.01.002. [DOI] [PubMed] [Google Scholar]
  • 22.Scorsetti M., Bignardi M., Alongi F. Stereotactic body radiation therapy for abdominal targets using volumetric intensity modulated arc therapy with RapidArc: feasibility and clinical preliminary results. Acta Oncol Stockh Swed. 2011;50(4):528–538. doi: 10.3109/0284186X.2011.558522. [DOI] [PubMed] [Google Scholar]
  • 23.Van De Voorde L., Vanneste B., Houben R. Image-guided stereotactic ablative radiotherapy for the liver: a safe and effective treatment. Eur J Surg Oncol J Eur Soc Surg Oncol Br Assoc Surg Oncol. 2015;41(2):249–256. doi: 10.1016/j.ejso.2014.10.053. [DOI] [PubMed] [Google Scholar]
  • 24.Wulf J., Guckenberger M., Haedinger U. Stereotactic radiotherapy of primary liver cancer and hepatic metastases. Acta Oncol. 2006;45(7):838–847. doi: 10.1080/02841860600904821. [DOI] [PubMed] [Google Scholar]
  • 25.Méndez Romero A, Keskin-Cambay F, van Os RM, et al. Institutional experience in the treatment of colorectal liver metastases with stereotactic body radiation therapy. Rep Pract Oncol Radiother 2017;22(2):126–31, http://dx.doi.org/10.1016/j.rpor.2016.10.003. [DOI] [PMC free article] [PubMed]
  • 26.Ambrosino G., Polistina F., Costantin G. Image-guided robotic stereotactic radiosurgery for unresectable liver metastases: preliminary results. Anticancer Res. 2009;29(8):3381–3384. [PubMed] [Google Scholar]
  • 27.Goodman K.A., Wiegner E.A., Maturen K.E. Dose-escalation study of single-fraction stereotactic body radiotherapy for liver malignancies. Int J Radiat Oncol. 2010;78(2):486–493. doi: 10.1016/j.ijrobp.2009.08.020. [DOI] [PubMed] [Google Scholar]
  • 28.Stintzing S., Hoffmann R.T., Heinemann V., Kufeld M., Muacevic A. Frameless single-session robotic radiosurgery of liver metastases in colorectal cancer patients. Eur J Cancer Oxf Engl 1990. 2010;46(6):1026–1032. doi: 10.1016/j.ejca.2010.01.008. [DOI] [PubMed] [Google Scholar]
  • 29.Vautravers-Dewas C., Dewas S., Bonodeau F. Image-guided robotic stereotactic body radiation therapy for liver metastases: is there a dose response relationship? Int J Radiat Oncol Biol Phys. 2011;81(3):e39–e47. doi: 10.1016/j.ijrobp.2010.12.047. [DOI] [PubMed] [Google Scholar]
  • 30.Katz A.W., Carey-Sampson M., Muhs A.G., Milano M.T., Schell M.C., Okunieff P. Hypofractionated stereotactic body radiation therapy (SBRT) for limited hepatic metastases. Int J Radiat Oncol. 2007;67(3):793–798. doi: 10.1016/j.ijrobp.2006.10.025. [DOI] [PubMed] [Google Scholar]
  • 31.Llacer Moscardo C. Imaged-guided liver SBRT using VMAT and real-time adaptive tumor gating. Rep Pract Oncol Radiother 2017;22(2):141–9, http://dx.doi.org/10.1016/j.rpor.2016.06.004. [DOI] [PMC free article] [PubMed]
  • 32.Sterzing F., Brunner T.B., Ernst I. Stereotactic body radiotherapy for liver tumors: principles and practical guidelines of the DEGRO Working Group on Stereotactic Radiotherapy. Strahlenther Onkol Organ Dtsch Röntgenges Al. 2014;190(10):872–881. doi: 10.1007/s00066-014-0714-1. [DOI] [PubMed] [Google Scholar]
  • 33.Wolthaus J.W.H., Sonke J.-J., van Herk M. Comparison of different strategies to use four-dimensional computed tomography in treatment planning for lung cancer patients. Int J Radiat Oncol Biol Phys. 2008;70(4):1229–1238. doi: 10.1016/j.ijrobp.2007.11.042. [DOI] [PubMed] [Google Scholar]
  • 34.Tanenbaum D., Hall W.A., Mittal P. Radiographic to pathologic correlation of gross tumor size of hepatic metastases from colorectal cancer. Int J Radiat Oncol Biol Phys. 2015;93(3):S205. [Google Scholar]
  • 35.Gabryś D., Kulik R., Trela K., Ślosarek K. Dosimetric comparison of liver tumour radiotherapy in all respiratory phases and in one phase using 4DCT. Radiother Oncol. 2011;100(3):360–364. doi: 10.1016/j.radonc.2011.09.006. [DOI] [PubMed] [Google Scholar]
  • 36.Hof H., Rhein B., Haering P., Kopp-Schneider A., Debus J., Herfarth K. 4D-CT-based target volume definition in stereotactic radiotherapy of lung tumours: comparison with a conventional technique using individual margins. Radiother Oncol. 2009;93(3):419–423. doi: 10.1016/j.radonc.2009.08.040. [DOI] [PubMed] [Google Scholar]
  • 37.Xi M., Liu M.-Z., Deng X.-W. Defining internal target volume (ITV) for hepatocellular carcinoma using four-dimensional CT. Radiother Oncol. 2007;84(3):272–278. doi: 10.1016/j.radonc.2007.07.021. [DOI] [PubMed] [Google Scholar]
  • 38.Ge J., Santanam L., Noel C., Parikh P.J. Planning 4-dimensional computed tomography (4DCT) cannot adequately represent daily intrafractional motion of abdominal tumors. Int J Radiat Oncol. 2013;85(4):999–1005. doi: 10.1016/j.ijrobp.2012.09.014. [DOI] [PubMed] [Google Scholar]
  • 39.Riou O., Serrano B., Azria D. Integrating respiratory-gated PET-based target volume delineation in liver SBRT planning, a pilot study. Radiat Oncol Lond Engl. 2014;9:127. doi: 10.1186/1748-717X-9-127. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 40.Deshayes E., Santoro L., Eberle M. Feasibility and clinical utility of 4D PET/CT for SBRT planning of liver tumors. Eur J Nucl Med Mol Imaging. 2015;42:S267–S268. [Google Scholar]
  • 41.Bundschuh R.A., Andratschke N., Dinges J. Respiratory gated [(18)F]FDG PET/CT for target volume delineation in stereotactic radiation treatment of liver metastases. Strahlenther Onkol Organ Dtsch Rontgengesellschaft Al. 2012;188(7):592–598. doi: 10.1007/s00066-012-0094-3. [DOI] [PubMed] [Google Scholar]
  • 42.Lochan R., White S.A., Manas D.M. Liver resection for colorectal liver metastasis. Surg Oncol. 2007;16(1):33–45. doi: 10.1016/j.suronc.2007.04.010. [DOI] [PubMed] [Google Scholar]
  • 43.Pawlik T.M., Izzo F., Cohen D.S., Morris J.S., Curley S.A. Combined resection and radiofrequency ablation for advanced hepatic malignancies: results in 172 patients. Ann Surg Oncol. 2003;10(9):1059–1069. doi: 10.1245/ASO.2003.03.026. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 44.Boutros C., Espat N.J. What, how, and when to offer nonresectional therapy for colorectal cancer liver metastases. J Gastrointest Surg Off J Soc Surg Aliment Tract. 2011;15(3):420–422. doi: 10.1007/s11605-011-1428-7. [DOI] [PubMed] [Google Scholar]
  • 45.Dawood O., Mahadevan A., Goodman K.A. Stereotactic body radiation therapy for liver metastases. Eur J Cancer Oxf Engl 1990. 2009;45(17):2947–2959. doi: 10.1016/j.ejca.2009.08.011. [DOI] [PubMed] [Google Scholar]
  • 46.Hawkins M.A., Brock K.K., Eccles C., Moseley D., Jaffray D., Dawson L.A. Assessment of residual error in liver position using kV cone-beam computed tomography for liver cancer high-precision radiation therapy. Int J Radiat Oncol. 2006;66(2):610–619. doi: 10.1016/j.ijrobp.2006.03.026. [DOI] [PubMed] [Google Scholar]
  • 47.Dawson L.A., Eccles C., Bissonnette J.-P., Brock K.K. Accuracy of daily image guidance for hypofractionated liver radiotherapy with active breathing control. Int J Radiat Oncol. 2005;62(4):1247–1252. doi: 10.1016/j.ijrobp.2005.03.072. [DOI] [PubMed] [Google Scholar]
  • 48.Hansen A.T., Petersen J.B., Høyer M. Internal movement, set-up accuracy and margins for stereotactic body radiotherapy using a stereotactic body frame. Acta Oncol Stockh Swed. 2006;45(7):948–952. doi: 10.1080/02841860600911172. [DOI] [PubMed] [Google Scholar]

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