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Romesser PB, Tyagi N, Crane CH. Magnetic Resonance Imaging-Guided Adaptive Radiotherapy for Colorectal Liver Metastases. Cancers (Basel) 2021; 13:cancers13071636. [PMID: 33915810 PMCID: PMC8036824 DOI: 10.3390/cancers13071636] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 03/22/2021] [Accepted: 03/28/2021] [Indexed: 12/16/2022] Open
Abstract
Technological advances have enabled well tolerated and effective radiation treatment for small liver metastases. Stereotactic ablative radiation therapy (SABR) refers to ablative dose delivery (>100 Gy BED) in five fractions or fewer. For larger tumors, the safe delivery of SABR can be challenging due to a more limited volume of healthy normal liver parenchyma and the proximity of the tumor to radiosensitive organs such as the stomach, duodenum, and large intestine. In addition to stereotactic treatment delivery, controlling respiratory motion, the use of image guidance, adaptive planning and increasing the number of radiation fractions are sometimes necessary for the safe delivery of SABR in these situations. Magnetic Resonance (MR) image-guided adaptive radiation therapy (MRgART) is a new and rapidly evolving treatment paradigm. MR imaging before, during and after treatment delivery facilitates direct visualization of both the tumor target and the adjacent normal healthy organs as well as potential intrafraction motion. Real time MR imaging facilitates non-invasive tumor tracking and treatment gating. While daily adaptive re-planning permits treatment plans to be adjusted based on the anatomy of the day. MRgART therapy is a promising radiation technology advance that can overcome many of the challenges of liver SABR and may facilitate the safe tumor dose escalation of colorectal liver metastases.
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Affiliation(s)
- Paul B. Romesser
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
- Early Drug Development Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
| | - Neelam Tyagi
- Department of Medical Physics, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
| | - Christopher H. Crane
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA;
- Correspondence:
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Abstract
Stereotactic ablative radiotherapy (SABR) commonly is used for small liver metastases. Modern conformal radiotherapy techniques, including 3-dimensional conformal radiotherapy and intensity-modulated radiation therapy, enable the safe delivery of SABR to small liver volumes. For larger tumors, the safe delivery of SABR can be challenging due to a more limited volume of healthy normal liver parenchyma and the proximity of the tumor to radiosensitive organs, such as the stomach, duodenum, and large intestine. Controlling respiratory motion, the use of image guidance, and increasing the number of radiation fractions sometimes are necessary for the safe delivery of SABR in these situations.
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Affiliation(s)
- Paul B Romesser
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box #22, New York, NY 10065, USA; Early Drug Development Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box #22, New York, NY 10065, USA
| | - Brian P Neal
- Medical Physics, ProCure Proton Therapy Center, 103 Cedar Grove Lane, Somerset, NJ 08873, USA
| | - Christopher H Crane
- Department of Radiation Oncology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box #22, New York, NY 10065, USA.
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Shiinoki T, Hanazawa H, Yuasa Y, Fujimoto K, Uehara T, Shibuya K. Verification of respiratory-gated radiotherapy with new real-time tumour-tracking radiotherapy system using cine EPID images and a log file. Phys Med Biol 2017; 62:1585-1599. [PMID: 28072584 DOI: 10.1088/1361-6560/aa587d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A combined system comprising the TrueBeam linear accelerator and a new real-time tumour-tracking radiotherapy system, SyncTraX, was installed at our institution. The objectives of this study are to develop a method for the verification of respiratory-gated radiotherapy with SyncTraX using cine electronic portal image device (EPID) images and a log file and to verify this treatment in clinical cases. Respiratory-gated radiotherapy was performed using TrueBeam and the SyncTraX system. Cine EPID images and a log file were acquired for a phantom and three patients during the course of the treatment. Digitally reconstructed radiographs (DRRs) were created for each treatment beam using a planning CT set. The cine EPID images, log file, and DRRs were analysed using a developed software. For the phantom case, the accuracy of the proposed method was evaluated to verify the respiratory-gated radiotherapy. For the clinical cases, the intra- and inter-fractional variations of the fiducial marker used as an internal surrogate were calculated to evaluate the gating accuracy and set-up uncertainty in the superior-inferior (SI), anterior-posterior (AP), and left-right (LR) directions. The proposed method achieved high accuracy for the phantom verification. For the clinical cases, the intra- and inter-fractional variations of the fiducial marker were ⩽3 mm and ±3 mm in the SI, AP, and LR directions. We proposed a method for the verification of respiratory-gated radiotherapy with SyncTraX using cine EPID images and a log file and showed that this treatment is performed with high accuracy in clinical cases.
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Affiliation(s)
- Takehiro Shiinoki
- Department of Radiation Oncology, Graduate School of Medicine, Yamaguchi University, 1-1-1 Minamikogushi, Yamaguchi 755-8535, Japan
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Crane CH, Koay EJ. Solutions that enable ablative radiotherapy for large liver tumors: Fractionated dose painting, simultaneous integrated protection, motion management, and computed tomography image guidance. Cancer 2016; 122:1974-86. [PMID: 26950735 DOI: 10.1002/cncr.29878] [Citation(s) in RCA: 61] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Revised: 11/04/2015] [Accepted: 11/05/2015] [Indexed: 12/13/2022]
Abstract
The emergence and success of stereotactic body radiation therapy (SBRT) for the treatment of lung cancer have led to its rapid adoption for liver cancers. SBRT can achieve excellent results for small liver tumors. However, the vast majority of physicians interpret SBRT as meaning doses of radiation (range, 4-20 Gray [Gy]) that may not be ablative but are delivered within about 1 week (ie, in 3-6 fractions). Adherence to this approach has limited the effectiveness of SBRT for large liver tumors (>7 cm) because of the need to reduce doses to meet organ constraints. The prognosis for patients who present with large liver tumors is poor, with a median survival ≤12 months, and most of these patients die from tumor-related liver failure. Herein, the authors present a comprehensive solution to achieve ablative SBRT doses for patients with large liver tumors by using a combination of classic, modern, and novel concepts of radiotherapy: fractionation, dose painting, motion management, image guidance, and simultaneous integrated protection. The authors discuss these concepts in the context of large, inoperable liver tumors and review how this approach can substantially prolong survival for patients, most of whom otherwise have a very poor prognosis and few effective treatment options. Cancer 2016;122:1974-86. © 2016 American Cancer Society.
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Affiliation(s)
- Christopher H Crane
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
| | - Eugene J Koay
- Department of Radiation Oncology, The University of Texas MD Anderson Cancer Center, Houston, Texas
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Winter JD, Wong R, Swaminath A, Chow T. Accuracy of Robotic Radiosurgical Liver Treatment Throughout the Respiratory Cycle. Int J Radiat Oncol Biol Phys 2015; 93:916-24. [DOI: 10.1016/j.ijrobp.2015.08.031] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 08/12/2015] [Accepted: 08/17/2015] [Indexed: 12/31/2022]
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Bonnes pratiques de radiothérapie guidée par l’image. Cancer Radiother 2015; 19:489-500. [DOI: 10.1016/j.canrad.2015.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 06/16/2015] [Indexed: 11/22/2022]
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Kishan AU, Cao M, Wang PC, Mikaeilian AG, Tenn S, Rwigema JCM, Sheng K, Low DA, Kupelian PA, Steinberg ML, Lee P. Feasibility of magnetic resonance imaging-guided liver stereotactic body radiation therapy: A comparison between modulated tri-cobalt-60 teletherapy and linear accelerator-based intensity modulated radiation therapy. Pract Radiat Oncol 2015; 5:330-337. [PMID: 25823383 DOI: 10.1016/j.prro.2015.02.014] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Revised: 02/20/2015] [Accepted: 02/27/2015] [Indexed: 11/26/2022]
Abstract
PURPOSE The purpose of this study was to investigate the dosimetric feasibility of liver stereotactic body radiation therapy (SBRT) using a teletherapy system equipped with 3 rotating (60)Co sources (tri-(60)Co system) and a built-in magnetic resonance imager (MRI). We hypothesized tumor size and location would be predictive of favorable dosimetry with tri-(60)Co SBRT. METHODS AND MATERIALS The primary study population consisted of 11 patients treated with SBRT for malignant hepatic lesions whose linear accelerator (LINAC)-based SBRT plans met all mandatory Radiation Therapy Oncology Group (RTOG) 1112 organ-at-risk (OAR) constraints. The secondary study population included 5 additional patients whose plans did not meet the mandatory constraints. Patients received 36 to 60 Gy in 3 to 5 fractions. Tri-(60)Co system SBRT plans were planned with ViewRay system software. RESULTS All patients in the primary study population had tri-(60)Co SBRT plans that passed all RTOG constraints, with similar planning target volume coverage and OAR doses to LINAC plans. Mean liver doses and V10Gy to the liver, although easily meeting RTOG 1112 guidelines, were significantly higher with tri-(60)Co plans. When the 5 additional patients were included in a univariate analysis, the tri-(60)Co SBRT plans were still equally able to pass RTOG constraints, although they did have inferior ability to pass more stringent liver and kidney constraints (P < .05). A multivariate analysis found the ability of a tri-(60)Co SBRT plan to meet these constraints depended on lesion location and size. Patients with smaller or more peripheral lesions (as defined by distance from the aorta, chest wall, liver dome, and relative lesion volume) were significantly more likely to have tri-(60)Co plans that spared the liver and kidney as well as LINAC plans did (P < .05). CONCLUSIONS It is dosimetrically feasible to perform liver SBRT with a tri-(60)Co system with a built-in MRI. Patients with smaller or more peripheral lesions are more likely to have optimal liver and kidney sparing, with the added benefit of MRI guidance, when receiving tri-(60)Co-based SBRT.
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Affiliation(s)
- Amar U Kishan
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Minsong Cao
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Pin-Chieh Wang
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Argin G Mikaeilian
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Stephen Tenn
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Jean-Claude M Rwigema
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Ke Sheng
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Daniel A Low
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Patrick A Kupelian
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Michael L Steinberg
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Percy Lee
- Department of Radiation Oncology, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California.
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Simeonova AO, Fleckenstein K, Wertz H, Frauenfeld A, Boda-Heggemann J, Lohr F, Wenz F. Are three doses of stereotactic ablative radiotherapy (SABR) more effective than 30 doses of conventional radiotherapy? Transl Lung Cancer Res 2015; 1:45-53. [PMID: 25806154 DOI: 10.3978/j.issn.2218-6751.10.01] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2011] [Accepted: 10/24/2011] [Indexed: 12/29/2022]
Abstract
In early stage non-small cell lung cancer (NSCLC) definitive radiation therapy is an appropriate alternative to surgery. Recent studies show, that in such patients hypofractionation schedules (for example 3 times 18 Gy or 5 times 12 Gy), can be safely applied, without causing severe toxicities and achieving high local control rates of up to 90% and more. In the last couple of years a lot of knowledge about the cancer biology, technical aspects, clinical outcomes and toxicities has been accumulated from different clinical trials. The purpose of this review is to summarize recent outcomes and developments in stereotactic radiation therapy for patients with early stage NSCLC.
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Affiliation(s)
- Anna O Simeonova
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
| | - Katharina Fleckenstein
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
| | - Hansjörg Wertz
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
| | - Anian Frauenfeld
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
| | - Judit Boda-Heggemann
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
| | - Frank Lohr
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
| | - Frederik Wenz
- Department of Radiation Oncology, University Medical Center Mannheim, University of Heidelberg, Mannheim, Germany
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Serpa M, Baier K, Cremers F, Guckenberger M, Meyer J. Suitability of markerless EPID tracking for tumor position verification in gated radiotherapy. Med Phys 2014; 41:031702. [PMID: 24593706 DOI: 10.1118/1.4863597] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
PURPOSE To maximize the benefits of respiratory gated radiotherapy (RGRT) of lung tumors real-time verification of the tumor position is required. This work investigates the feasibility of markerless tracking of lung tumors during beam-on time in electronic portal imaging device (EPID) images of the MV therapeutic beam. METHODS EPID movies were acquired at ∼2 fps for seven lung cancer patients with tumor peak-to-peak motion ranges between 7.8 and 17.9 mm (mean: 13.7 mm) undergoing stereotactic body radiotherapy. The external breathing motion of the abdomen was synchronously measured. Both datasets were retrospectively analyzed in PortalTrack, an in-house developed tracking software. The authors define a three-step procedure to run the simulations: (1) gating window definition, (2) gated-beam delivery simulation, and (3) tumor tracking. First, an amplitude threshold level was set on the external signal, defining the onset of beam-on/-off signals. This information was then mapped onto a sequence of EPID images to generate stamps of beam-on/-hold periods throughout the EPID movies in PortalTrack, by obscuring the frames corresponding to beam-off times. Last, tumor motion in the superior-inferior direction was determined on portal images by the tracking algorithm during beam-on time. The residual motion inside the gating window as well as target coverage (TC) and the marginal target displacement (MTD) were used as measures to quantify tumor position variability. RESULTS Tumor position monitoring and estimation from beam's-eye-view images during RGRT was possible in 67% of the analyzed beams. For a reference gating window of 5 mm, deviations ranging from 2% to 86% (35% on average) were recorded between the reference and measured residual motion. TC (range: 62%-93%; mean: 77%) losses were correlated with false positives incidence rates resulting mostly from intra-/inter-beam baseline drifts, as well as sudden cycle-to-cycle fluctuations in exhale positions. Both phenomena can lead to considerable deviations (with MTD values up to a maximum of 7.8 mm) from the intended tumor position, and in turn may result in a marginal miss. The difference between tumor traces determined within the gating window against ground truth trajectory maps was 1.1 ± 0.7 mm on average (range: 0.4-2.3 mm). CONCLUSIONS In this retrospective analysis of motion data, it is demonstrated that the system is capable of determining tumor positions in the plane perpendicular to the beam direction without the aid of fiducial markers, and may hence be suitable as an online verification tool in RGRT. It may be possible to use the tracking information to enable on-the-fly corrections to intra-/inter-beam variations by adapting the gating window by means of a robotic couch.
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Affiliation(s)
- Marco Serpa
- Institute for Research and Development on Advanced Radiation Technologies (radART), Paracelsus Medical University, 5020 Salzburg, Austria; University Clinic for Radiotherapy and Radio-Oncology, Landeskrankenhaus Salzburg, Paracelsus Medical University Clinics, 5020 Salzburg, Austria; and Department of Physics and Astronomy, University of Canterbury, Christchurch 8140, New Zealand
| | - Kurt Baier
- Department of Radiation Oncology, University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Florian Cremers
- Department of Radiation Oncology, University Medical Center Hamburg Eppendorf, D-20246 Hamburg, Germany
| | - Matthias Guckenberger
- Department of Radiation Oncology, University of Wuerzburg, D-97080 Wuerzburg, Germany
| | - Juergen Meyer
- Department of Radiation Oncology, University of Washington, Seattle, Washington 98195, USA
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Velec M, Moseley JL, Dawson LA, Brock KK. Dose escalated liver stereotactic body radiation therapy at the mean respiratory position. Int J Radiat Oncol Biol Phys 2014; 89:1121-1128. [PMID: 25035217 DOI: 10.1016/j.ijrobp.2014.04.051] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2014] [Revised: 04/04/2014] [Accepted: 04/25/2014] [Indexed: 12/25/2022]
Abstract
PURPOSE The dosimetric impact of dose probability based planning target volume (PTV) margins for liver cancer patients receiving stereotactic body radiation therapy (SBRT) was compared with standard PTV based on the internal target volume (ITV). Plan robustness was evaluated by accumulating the treatment dose to ensure delivery of the intended plan. METHODS AND MATERIALS Twenty patients planned on exhale CT for 27 to 50 Gy in 6 fractions using an ITV-based PTV and treated free-breathing were retrospectively evaluated. Isotoxic, dose escalated plans were created on midposition computed tomography (CT), representing the mean breathing position, using a dose probability PTV. The delivered doses were accumulated using biomechanical deformable registration of the daily cone beam CT based on liver targeting at the exhale or mean breathing position, for the exhale and midposition CT plans, respectively. RESULTS The dose probability PTVs were on average 38% smaller than the ITV-based PTV, enabling an average ± standard deviation increase in the planned dose to 95% of the PTV of 4.0 ± 2.8 Gy (9 ± 5%) on the midposition CT (P<.01). For both plans, the delivered minimum gross tumor volume (GTV) doses were greater than the planned nominal prescribed dose in all 20 patients and greater than the planned dose to 95% of the PTV in 18 (90%) patients. Nine patients (45%) had 1 or more GTVs with a delivered minimum dose more than 5 Gy higher with the midposition CT plan using dose probability PTV, compared with the delivered dose with the exhale CT plan using ITV-based PTV. CONCLUSIONS For isotoxic liver SBRT planned and delivered at the mean respiratory, reduced dose probability PTV enables a mean escalation of 4 Gy (9%) in 6 fractions over ITV-based PTV. This may potentially improve local control without increasing the risk of tumor underdosing.
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Affiliation(s)
- Michael Velec
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada.
| | - Joanne L Moseley
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada
| | - Laura A Dawson
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada
| | - Kristy K Brock
- Radiation Medicine Program, Princess Margaret Cancer Centre, Toronto, Ontario, Canada; Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Toronto, Toronto, Ontario, Canada; Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan
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An S, Yeo I, Jung J, Suh H, Lee KJ, Choi J, Lee KC, Lee R. The Effect of Breathing Biofeedback on Breathing Reproducibility and Patient's Dose in Respiration-gated Radiotherapy. ACTA ACUST UNITED AC 2013. [DOI: 10.14316/pmp.2013.24.3.135] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Affiliation(s)
- Sohyun An
- Department of Radiation Oncology, Gachon University Gil Medical Center, Incheon, Korea
| | - Inhwan Yeo
- Department of Radiation Medicine, Loma Linda University Medical Center, Loma Linda, CA, USA
| | - Jaewon Jung
- Department of Physics, East Carolina University, Greenville, NC, USA
| | - Hyunsuk Suh
- Department of Radiation Oncology, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Kyung Ja Lee
- Department of Radiation Oncology, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Jinho Choi
- Department of Radiation Oncology, Gachon University Gil Medical Center, Incheon, Korea
| | - Kyu Chan Lee
- Department of Radiation Oncology, Gachon University Gil Medical Center, Incheon, Korea
| | - Rena Lee
- Department of Radiation Oncology, School of Medicine, Ewha Womans University, Seoul, Korea
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Mohammadi M, Bezak E. Evaluation of relative transmitted dose for a step and shoot head and neck intensity modulated radiation therapy using a scanning liquid ionization chamber electronic portal imaging device. J Med Phys 2012; 37:14-26. [PMID: 22363108 PMCID: PMC3283912 DOI: 10.4103/0971-6203.92716] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 09/29/2011] [Accepted: 10/06/2011] [Indexed: 11/13/2022] Open
Abstract
The dose delivery verification for a head and neck static intensity modulated radiation therapy (IMRT) case using a scanning liquid ionization chamber electronic portal imaging device (SLIC-EPID) was investigated. Acquired electronic portal images were firstly converted into transmitted dose maps using an in-house developed method. The dose distributions were then compared with those calculated in a virtual EPID using the Pinnacle3 treatment planning system (TPS). Using gamma evaluation with the ΔDmax and DTA criteria of 3%/2.54 mm, an excellent agreement was observed between transmitted dose measured using SLIC-EPID and that calculated by TPS (gamma score approximately 95%) for large MLC fields. In contrast, for several small subfields, due to SLIC-EPID image blurring, significant disagreement was found in the gamma results. Differences between EPID and TPS dose maps were also observed for several parts of the radiation subfields, when the radiation beam passed through air on the outside of tissue. The transmitted dose distributions measured using portal imagers such as SLIC-EPID can be used to verify the dose delivery to a patient. However, several aspects such as accurate calibration procedure and imager response under different conditions should be taken into the consideration. In addition, SLIC-EPID image blurring is another important issue, which should be considered if the SLIC-EPID is used for clinical dosimetry verification.
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Abstract
Historically, the use of external-beam radiotherapy for hepatocellular carcinoma (HCC) has been limited by toxicity to the uninvolved liver and surrounding structures. Advances in photon radiotherapy have improved dose conformality to the tumor and facilitated dose escalation, a key contributor to improved HCC radiation treatment outcomes. However, despite these advances in photon radiotherapy, significant volumes of liver still receive low doses of radiation that can preclude dose escalation, particularly in patients with limited functional liver reserves. By capitalizing on the lack of exit dose along the beam path beyond the tumor and higher biological effectiveness, charged-particle therapy offers the promise of maximizing tumor control via dose escalation without excessive liver toxicity. In this review, we discuss the distinctive biophysical attributes of both proton and carbon ion radiotherapy, particularly as they pertain to treatment of HCC. We also review the available literature regarding clinical outcomes and the toxicity of using charged particles for the treatment of HCC.
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Affiliation(s)
- Heath D. Skinner
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX
| | - Theodore S. Hong
- Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Sunil Krishnan
- Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, TX
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Abstract
Adaptive radiation therapy for liver cancer has the potential to reduce normal tissue complications and enable dose escalation, allowing the potential for tumor control in this challenging site. Using adaptive techniques to tailor treatment margins to reflect patient-specific breathing motions and image-guidance techniques can reduce the high dose delivered to surrounding normal tissues while ensuring that the prescription dose is delivered to the tumor. Several treatment planning and delivery techniques have been developed for use in the liver, including a margin to encompass the full breathing motion, mean position techniques, which evaluate the probability of tumor location during breathing, breath hold, gating, and tracking. Patient selection, clinical workflow, and quality assurance must be considered and developed before integrating these techniques into clinical practice.
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Affiliation(s)
- Kristy K Brock
- Department of Radiation Oncology, Princess Margaret Hospital, University Health Network, University of Toronto, Toronto, ON, Canada.
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Jacso F, Kouznetsov A, Smith WL. Development and evaluation of an ultrasound-guided tracking and gating system for hepatic radiotherapy. Med Phys 2009; 36:5633-40. [DOI: 10.1118/1.3250893] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
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