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Litzenberg DW, Muenz DG, Archer PG, Jackson WC, Hamstra DA, Hearn JW, Schipper MJ, Spratt DE. Changes in prostate orientation due to removal of a Foley catheter. Med Phys 2018; 45:1369-1378. [PMID: 29474748 DOI: 10.1002/mp.12830] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2017] [Revised: 01/31/2018] [Accepted: 01/31/2018] [Indexed: 11/09/2022] Open
Abstract
PURPOSE Investigate the impact on prostate orientation caused by use and removal of a Foley catheter, and the dosimetric impact on men prospectively treated with prostate stereotactic body radiotherapy (SBRT). METHODS Twenty-two men underwent a CT simulation with a Foley in place (FCT), followed immediately by a second treatment planning simulation without the Foley (TPCT). The change in prostate orientation was determined by rigid registration of three implanted transponders between FCT and TPCT and compared to measured orientation changes during treatment. The impact on treatment planning and delivery was investigated by analyzing the measured rotations during treatment relative to both CT scans, and introducing rotations of ±15° in the treatment plan to determine the maximum impact of allowed rotations. RESULTS Removing the Foley caused a statistically significant prostate rotation (P < 0.0028) compared to normal biological motion in 60% of patients. The largest change in rotation due to removing a Foley occurs about the left-right axis (tilt) which has a standard deviation two to five times larger than changes in rotation about the Sup-Inf (roll) and Ant-Post (yaw) axes. The change in tilt due to removing a Foley for prone and supine patients was -1.1° ± 6.0° and 0.3° ± 7.4°, showing no strong directional bias. The average tilt during treatment was -1.6° ± 7.1° compared to the TPCT and would have been -2.0° ± 7.1° had the FCT been used as the reference. The TPCT was a better or equivalent representation of prostate tilt in 82% of patients, vs 50% had the FCT been used for treatment planning. However, 92.7% of fractions would still have been within the ±15° rotation limit if only the FCT were used for treatment planning. When rotated ±15°, urethra V105% = 38.85Gy < 20% was exceeded in 27% of the instances, and prostate (CTV) coverage was maintained above D95% > 37 Gy in all but one instance. CONCLUSIONS Removing a Foley catheter can cause large prostate rotations. There does not appear to be a clear dosimetric benefit to obtaining the CT scan with a Foley catheter to define the urethra given the changes in urethral position from removing the Foley catheter. If urethral sparing is desired without the use of a Foley, utilization of an MRI to define the urethra may be necessary, or a pseudo-urethral planning organ at risk volume (PRV) may be used to limit dosimetric hot spots.
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Affiliation(s)
- Dale W Litzenberg
- Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109-5010, USA
| | - Daniel G Muenz
- Department of Biostatistics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Paul G Archer
- Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109-5010, USA
| | - William C Jackson
- Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109-5010, USA
| | - Daniel A Hamstra
- Radiation Oncology, Beaumont Health System, Royal Oak, MI, 48073, USA
| | - Jason W Hearn
- Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109-5010, USA
| | - Matthew J Schipper
- Departments of Radiation Oncology and Biostatistics, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Daniel E Spratt
- Radiation Oncology, University of Michigan, Ann Arbor, MI, 48109-5010, USA
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Kim JH, Nguyen DT, Booth JT, Huang CY, Fuangrod T, Poulsen P, O'Brien R, Caillet V, Eade T, Kneebone A, Keall P. The accuracy and precision of Kilovoltage Intrafraction Monitoring (KIM) six degree-of-freedom prostate motion measurements during patient treatments. Radiother Oncol 2018; 126:236-243. [PMID: 29471970 DOI: 10.1016/j.radonc.2017.10.030] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2017] [Revised: 10/17/2017] [Accepted: 10/22/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND AND PURPOSE To perform a quantitative analysis of the accuracy and precision of Kilovoltage Intrafraction Monitoring (KIM) six degree-of-freedom (6DoF) prostate motion measurements during treatments. MATERIAL AND METHODS Real-time 6DoF prostate motion was acquired using KIM for 14 prostate cancer patients (377 fractions). KIM outputs the 6DoF prostate motion, combining 3D translation and 3D rotational motion information relative to its planning position. The corresponding groundtruth target motion was obtained post-treatment based on kV/MV triangulation. The accuracy and precision of the 6DoF KIM motion estimates were calculated as the mean and standard deviation differences compared with the ground-truth. RESULTS The accuracy ± precision of real-time 6DoF KIM-measured prostate motion were 0.2 ± 1.3° for rotations and 0.1 ± 0.5 mm for translations, respectively. The magnitude of KIM-measured motion was well-correlated with the magnitude of ground-truth motion resulting in Pearson correlation coefficients of ≥0.88 in all DoF. CONCLUSIONS The results demonstrate that KIM is capable of providing the real-time 6DoF prostate target motion during patient treatments with an accuracy ± precision of within 0.2 ± 1.3° and 0.1 ± 0.5 mm for rotation and translation, respectively. As KIM only requires a single X-ray imager, which is available on most modern cancer radiotherapy devices, there is potential for widespread adoption of this technology.
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Affiliation(s)
- Jung-Ha Kim
- Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Australia
| | - Doan T Nguyen
- Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Australia
| | - Jeremy T Booth
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia; School of Physics, The University of Sydney, Australia
| | - Chen-Yu Huang
- Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Australia
| | - Todsaporn Fuangrod
- Department of Radiation Oncology, Calvary Mater Hospital, Newcastle, Australia
| | - Per Poulsen
- Department of Oncology, Aarhus University Hospital, Denmark
| | - Ricky O'Brien
- Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Australia
| | - Vincent Caillet
- Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Australia; Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia
| | - Thomas Eade
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia
| | - Andrew Kneebone
- Northern Sydney Cancer Centre, Royal North Shore Hospital, Australia
| | - Paul Keall
- Radiation Physics Laboratory, Sydney Medical School, The University of Sydney, Australia.
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3
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Dosimetric effect of uncorrected rotations in lung SBRT with stereotactic imaging guidance. Phys Med 2017; 42:197-202. [DOI: 10.1016/j.ejmp.2017.09.135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 09/20/2017] [Accepted: 09/23/2017] [Indexed: 12/25/2022] Open
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Kontaxis C, Bol GH, Kerkmeijer LGW, Lagendijk JJW, Raaymakers BW. Fast online replanning for interfraction rotation correction in prostate radiotherapy. Med Phys 2017; 44:5034-5042. [DOI: 10.1002/mp.12467] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2017] [Revised: 06/05/2017] [Accepted: 07/06/2017] [Indexed: 11/11/2022] Open
Affiliation(s)
- Charis Kontaxis
- Department of Radiotherapy; University Medical Center Utrecht; Heidelberglaan 100 Utrecht 3584 CX The Netherlands
| | - Gijsbert H. Bol
- Department of Radiotherapy; University Medical Center Utrecht; Heidelberglaan 100 Utrecht 3584 CX The Netherlands
| | - Linda G. W. Kerkmeijer
- Department of Radiotherapy; University Medical Center Utrecht; Heidelberglaan 100 Utrecht 3584 CX The Netherlands
| | - Jan J. W. Lagendijk
- Department of Radiotherapy; University Medical Center Utrecht; Heidelberglaan 100 Utrecht 3584 CX The Netherlands
| | - Bas W. Raaymakers
- Department of Radiotherapy; University Medical Center Utrecht; Heidelberglaan 100 Utrecht 3584 CX The Netherlands
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Fast MF, Kamerling CP, Ziegenhein P, Menten MJ, Bedford JL, Nill S, Oelfke U. Assessment of MLC tracking performance during hypofractionated prostate radiotherapy using real-time dose reconstruction. Phys Med Biol 2016; 61:1546-62. [PMID: 26816273 PMCID: PMC5390952 DOI: 10.1088/0031-9155/61/4/1546] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/25/2015] [Accepted: 12/16/2015] [Indexed: 11/16/2022]
Abstract
By adapting to the actual patient anatomy during treatment, tracked multi-leaf collimator (MLC) treatment deliveries offer an opportunity for margin reduction and healthy tissue sparing. This is assumed to be especially relevant for hypofractionated protocols in which intrafractional motion does not easily average out. In order to confidently deliver tracked treatments with potentially reduced margins, it is necessary to monitor not only the patient anatomy but also the actually delivered dose during irradiation. In this study, we present a novel real-time online dose reconstruction tool which calculates actually delivered dose based on pre-calculated dose influence data in less than 10 ms at a rate of 25 Hz. Using this tool we investigate the impact of clinical target volume (CTV) to planning target volume (PTV) margins on CTV coverage and organ-at-risk dose. On our research linear accelerator, a set of four different CTV-to-PTV margins were tested for three patient cases subject to four different motion conditions. Based on this data, we can conclude that tracking eliminates dose cold spots which can occur in the CTV during conventional deliveries even for the smallest CTV-to-PTV margin of 1 mm. Changes of organ-at-risk dose do occur frequently during MLC tracking and are not negligible in some cases. Intrafractional dose reconstruction is expected to become an important element in any attempt of re-planning the treatment plan during the delivery based on the observed anatomy of the day.
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Affiliation(s)
- M F Fast
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG, UK
| | - C P Kamerling
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG, UK
| | - P Ziegenhein
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG, UK
| | - M J Menten
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG, UK
| | - J L Bedford
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG, UK
| | - S Nill
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG, UK
| | - U Oelfke
- Joint Department of Physics, The Institute of Cancer Research and The Royal Marsden NHS Foundation Trust, London SM2 5NG, UK
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Law G, Leung R, Lee F, Luk H, Lee KC, Wong F, Wong M, Cheung S, Lee V, Mui WH, Chan M. Effectiveness of a Patient-Specific Immobilization and Positioning System to Limit Interfractional Translation and Rotation Setup Errors in Radiotherapy of Prostate Cancers. ACTA ACUST UNITED AC 2016. [DOI: 10.4236/ijmpcero.2016.53020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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de Boer J, Wolf AL, Szeto YZ, van Herk M, Sonke JJ. Dynamic Collimator Angle Adjustments During Volumetric Modulated Arc Therapy to Account for Prostate Rotations. Int J Radiat Oncol Biol Phys 2015; 91:1009-16. [DOI: 10.1016/j.ijrobp.2014.11.020] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2014] [Revised: 10/22/2014] [Accepted: 11/12/2014] [Indexed: 11/25/2022]
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8
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Roll and pitch set-up errors during volumetric modulated arc delivery. Strahlenther Onkol 2014; 191:272-80. [DOI: 10.1007/s00066-014-0766-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Accepted: 09/30/2014] [Indexed: 10/24/2022]
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Pearlstein KA, Chen RC. Comparing Dosimetric, Morbidity, Quality of Life, and Cancer Control Outcomes After 3D Conformal, Intensity-Modulated, and Proton Radiation Therapy for Prostate Cancer. Semin Radiat Oncol 2013; 23:182-90. [DOI: 10.1016/j.semradonc.2013.01.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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10
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Shang Q, Sheplan Olsen LJ, Stephans K, Tendulkar R, Xia P. Prostate rotation detected from implanted markers can affect dose coverage and cannot be simply dismissed. J Appl Clin Med Phys 2013; 14:4262. [PMID: 23652257 PMCID: PMC5714427 DOI: 10.1120/jacmp.v14i3.4262] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 01/29/2013] [Accepted: 01/25/2013] [Indexed: 11/23/2022] Open
Abstract
With implanted markers, daily prostate displacements can be automatically detected with six degrees of freedom. The reported magnitudes of the rotations, however, are often greater than the typical range of a six‐degree treatment couch. The purpose of this study is to quantify geometric and dosimetric effects if the prostate rotations are not corrected (ROT_NC) and if they can be compensated with translational shifts (ROT_C). Forty‐three kilovoltage cone‐beam CTs (KV‐CBCT) with implanted markers from five patients were available for this retrospective study. On each KV‐CBCT, the prostate, bladder, and rectum were manually contoured by a physician. The prostate contours from the planning CT and CBCT were aligned manually to achieve the best overlaps. This contour registration served as the benchmark method for comparison with two marker registration methods: (a) using six degrees of freedom, but rotations were not corrected (ROT_NC); and (b) using three degrees of freedom while compensating rotations into the translational shifts (ROT_C). The center of mass distance (CMD) and overlap index (OI) were used to evaluate these two methods. The dosimetric effects were also analyzed by comparing the dose coverage of the prostate clinical target volume (CTV) in relation to the planning margins. According to our analysis, the detected rotations dominated in the left–right axis with systematic and random components of 4.6° and 4.1°, respectively. When the rotation angles were greater than 10°, the differences in CMD between the two registrations were greater than 5 mm in 85.7% of these fractions; when the rotation angles were greater than 6°, the differences of CMD were greater than 4 mm in 61.1% of these fractions. With 6 mm/4 mm posterior planning margins, the average difference between the dose to 99% (D99) of the prostate in CBCTs and the planning D99 of the prostate was −8.0±12.3% for the ROT_NC registration, and −3.6±9.0% for the ROT_C registration (p=0.01). When the planning margin decreased to 4 mm/2 mm posterior, the average difference in D99 of the prostate was −22.0±16.2% and −15.1±15.2% for the ROT_NC and ROT_C methods, respectively (p<0.05). In conclusion, prostate rotation cannot be simply dismissed, and the impact of the rotational errors depends on the distance between the isocenter and the centroid of implanted markers and the rotation angle. PACS number: 87.55
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Affiliation(s)
- Qingyang Shang
- Department of Radiation Oncology, Cleveland Clinic, Cleveland, OH 44195, USA
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11
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Hybrid Registration of Prostate and Seminal Vesicles for Image Guided Radiation Therapy. Int J Radiat Oncol Biol Phys 2013; 86:177-82. [DOI: 10.1016/j.ijrobp.2012.11.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 11/19/2012] [Accepted: 11/26/2012] [Indexed: 11/19/2022]
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12
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Impact of inter- and intrafraction deviations and residual set-up errors on PTV margins. Strahlenther Onkol 2013; 189:321-8. [DOI: 10.1007/s00066-012-0303-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2012] [Accepted: 12/20/2012] [Indexed: 11/25/2022]
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13
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de Boer J, de Bois J, van Herk M, Sonke JJ. Influence of the number of elongated fiducial markers on the localization accuracy of the prostate. Phys Med Biol 2012; 57:6211-26. [PMID: 22975483 DOI: 10.1088/0031-9155/57/19/6211] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Implanting fiducial markers for localization purposes has become an accepted practice in radiotherapy for prostate cancer. While many correction strategies correct for translations only, advanced correction protocols also require knowledge of the rotation of the prostate. For this purpose, typically, three or more markers are implanted. Elongated fiducial markers provide more information about their orientation than traditional round or cylindrical markers. Potentially, fewer markers are required. In this study, we evaluate the effect of the number of elongated markers on the localization accuracy of the prostate. To quantify the localization error, we developed a model that estimates, at arbitrary locations in the prostate, the registration error caused by translational and rotational uncertainties of the marker registration. Every combination of one, two and three markers was analysed for a group of 24 patients. The average registration errors at the prostate surface were 0.3-0.8 mm and 0.4-1 mm for registrations on, respectively, three markers and two markers located on different sides of the prostate. Substantial registration errors (2.0-2.2 mm) occurred at the prostate surface contralateral to the markers when two markers were implanted on the same side of the prostate or only one marker was used. In conclusion, there is no benefit in using three elongated markers: two markers accurately localize the prostate if they are implanted at some distance from each other.
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Affiliation(s)
- Johan de Boer
- Department of Radiation Oncology, The Netherlands Cancer Institute - Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX, Amsterdam, The Netherlands
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Rosenfelder NA, Corsini L, McNair H, Pennert K, Burke K, Lamb CM, Aitken A, Ashley S, Khoo V, Brada M. Achieving the relocation accuracy of stereotactic frame-based cranial radiotherapy in a three-point thermoplastic shell. Clin Oncol (R Coll Radiol) 2012; 25:66-73. [PMID: 22795232 DOI: 10.1016/j.clon.2012.06.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Revised: 03/25/2012] [Accepted: 06/26/2012] [Indexed: 12/25/2022]
Abstract
AIMS To compare the accuracy of fractionated cranial radiotherapy in a standard three-point thermoplastic shell using daily online correction with accuracy in a Gill-Thomas-Cosman relocatable stereotactic frame. MATERIALS AND METHODS All patients undergoing fractionated radiotherapy for benign intracranial tumours between March 2009 and August 2010 were included. Patients were immobilised in the frame with those unable to tolerate it immobilised in the shell. The ExacTrac imaging system was used for verification/correction. Daily online imaging before and after correction was carried out for shell patients and systematic and random population set-up errors calculated. These were compared with frame patients who underwent standard departmental imaging/correction with fractions 1-3 and weekly thereafter. Set-up margins were calculated from population errors. RESULTS Systematic and random errors were 0.3-0.7 mm/° before correction and 0.1-0.2 mm/° after correction in all axes in the frame, and 0.6-1.5 mm/° before correction and 0.1-0.4 mm/° after correction in the shell. Isotropic margins required for patient set-up could be reduced from 2 mm to <1 mm in the frame and from 5 mm to <1 mm in the shell. CONCLUSION Similar set-up accuracy can be achieved in the standard thermoplastic shell as in a relocatable frame despite less precise immobilisation. The use of daily online correction precludes the need for larger set-up margins.
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Affiliation(s)
- N A Rosenfelder
- Department of Clinical Oncology, Royal Marsden NHS Foundation Trust, London, UK.
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Mutanga TF, de Boer HC, van der Wielen GJ, Hoogeman MS, Incrocci L, Heijmen BJ. Margin Evaluation in the Presence of Deformation, Rotation, and Translation in Prostate and Entire Seminal Vesicle Irradiation With Daily Marker-Based Setup Corrections. Int J Radiat Oncol Biol Phys 2011; 81:1160-7. [DOI: 10.1016/j.ijrobp.2010.09.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 08/23/2010] [Accepted: 09/26/2010] [Indexed: 11/30/2022]
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Wu J, Ruan D, Cho B, Sawant A, Petersen J, Newell LJ, Cattell H, Keall PJ. Electromagnetic detection and real-time DMLC adaptation to target rotation during radiotherapy. Int J Radiat Oncol Biol Phys 2011; 82:e545-53. [PMID: 22014957 DOI: 10.1016/j.ijrobp.2011.06.1958] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 05/10/2011] [Accepted: 06/01/2011] [Indexed: 12/01/2022]
Abstract
PURPOSE Intrafraction rotation of more than 45° and 25° has been observed for lung and prostate tumors, respectively. Such rotation is not routinely adapted to during current radiotherapy, which may compromise tumor dose coverage. The aim of the study was to investigate the geometric and dosimetric performance of an electromagnetically guided real-time dynamic multileaf collimator (DMLC) tracking system to adapt to intrafractional tumor rotation. MATERIALS/METHODS Target rotation was provided by changing the treatment couch angle. The target rotation was measured by a research Calypso system integrated with a real-time DMLC tracking system employed on a Varian linac. The geometric beam-target rotational alignment difference was measured using electronic portal images. The dosimetric accuracy was quantified using a two-dimensional ion chamber array. For each beam, the following five delivery modes were tested: 1) nonrotated target (reference); 2) fixed rotated target with tracking; 3) fixed rotated target without tracking; 4) actively rotating target with tracking; and 5) actively rotating target without tracking. Dosimetric performance of the latter four modes was measured and compared to the reference dose distribution using a 3 mm/3% γ-test. RESULTS Geometrically, the beam-target rotational alignment difference was 0.3° ± 0.6° for fixed rotation and 0.3° ± 1.3° for active rotation. Dosimetrically, the average failure rate for the γ-test for a fixed rotated target was 11% with tracking and 36% without tracking. The average failure rate for an actively rotating target was 9% with tracking and 35% without tracking. CONCLUSIONS For the first time, real-time target rotation has been accurately detected and adapted to during radiation delivery via DMLC tracking. The beam-target rotational alignment difference was mostly within 1°. Dose distributions to fixed and actively rotating targets with DMLC tracking were significantly superior to those without tracking.
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Affiliation(s)
- Junqing Wu
- Department of Radiation Oncology, Stanford University, Stanford, CA, USA
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17
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Prostate intrafraction translation margins for real-time monitoring and correction strategies. Prostate Cancer 2011; 2012:130579. [PMID: 22111005 PMCID: PMC3195290 DOI: 10.1155/2012/130579] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Accepted: 05/12/2011] [Indexed: 12/25/2022] Open
Abstract
The purpose of this work is to determine appropriate radiation therapy beam margins to account for intrafraction prostate translations for use with real-time electromagnetic position monitoring and correction strategies. Motion was measured continuously in 35 patients over 1157 fractions at 5 institutions. This data was studied using van Herk's formula of (αΣ + γσ') for situations ranging from no electromagnetic guidance to automated real-time corrections. Without electromagnetic guidance, margins of over 10 mm are necessary to ensure 95% dosimetric coverage while automated electromagnetic guidance allows the margins necessary for intrafraction translations to be reduced to submillimeter levels. Factors such as prostate deformation and rotation, which are not included in this analysis, will become the dominant concerns as margins are reduced. Continuous electromagnetic monitoring and automated correction have the potential to reduce prostate margins to 2-3 mm, while ensuring that a higher percentage of patients (99% versus 90%) receive a greater percentage (99% versus 95%) of the prescription dose.
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Peng JL, Liu C, Chen Y, Amdur RJ, Vanek K, Li JG. Dosimetric consequences of rotational setup errors with direct simulation in a treatment planning system for fractionated stereotactic radiotherapy. J Appl Clin Med Phys 2011; 12:3422. [PMID: 21844852 PMCID: PMC5718647 DOI: 10.1120/jacmp.v12i3.3422] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 01/07/2011] [Accepted: 01/31/2011] [Indexed: 11/23/2022] Open
Abstract
The purpose was to determine dose‐delivery errors resulting from systematic rotational setup errors for fractionated stereotactic radiotherapy using direct simulation in a treatment planning system. Ten patients with brain tumors who received intensity‐modulated radiotherapy had dose distributions re‐evaluated to assess the impact of systematic rotational setup errors. The dosimetric effect of rotational setup errors was simulated by rotating images and contours using a 3 by 3 rotational matrix. Combined rotational errors of ± 1°,± 3°,± 5° and ± 7° and residual translation errors of 1 mm along each axis were simulated. Dosimetric effects of the rotated images were evaluated by recomputing dose distributions and compared with the original plan. The mean volume of CTV that received the prescription dose decreased from 99.3%± 0.5% (original) to 98.6%± 1.6% (± 1°), 97.0%± 2.0% (± 3°), 93.1%± 4.6% (± 5°), and 87.8%± 14.2% (± 7°). Minimal changes in the cold and hot spots were seen in the CTV. In general, the increase in the volumes of the organs at risk (OARs) receiving the tolerance doses was small and did not exceed the tolerance, except for cases where the OARs were in close proximity to the PTV. For intracranial tumors treated with IMRT with a CTV‐to‐PTV margin of 3 mm, rotational setup errors of 3° or less didn't decrease the CTV coverage to less than 95% in most cases. However, for large targets with irregular or elliptical shapes, the target coverage decreased significantly as rotational errors of 5° or more were present. Our results indicate that setup margins are warranted even in the absence of translational setup errors to account for rotational setup errors. Rotational setup errors should be evaluated carefully for clinical cases involving large tumor sizes and for targets with elliptical or irregular shape, as well as when isocenter is away from the center of the PTV or OARs are in close proximity to the target volumes. PACS number: 87.53.Bn
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Affiliation(s)
- Jean L Peng
- Department of Radiation Oncology, Medical University of South Carolina, Charleston, South Carolina 29425, USA.
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On-line adaptive radiation therapy: feasibility and clinical study. JOURNAL OF ONCOLOGY 2010; 2010:407236. [PMID: 21113304 PMCID: PMC2990023 DOI: 10.1155/2010/407236] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Revised: 08/09/2010] [Accepted: 09/25/2010] [Indexed: 11/17/2022]
Abstract
The purpose of this paper is to evaluate the feasibility and clinical dosimetric benefit of an on-line, that is, with the patient in the treatment position, Adaptive Radiation Therapy (ART) system for prostate cancer treatment based on daily cone-beam CT imaging and fast volumetric reoptimization of treatment plans. A fast intensity-modulated radiotherapy (IMRT) plan reoptimization algorithm is implemented and evaluated with clinical cases. The quality of these adapted plans is compared to the corresponding new plans generated by an experienced planner using a commercial treatment planning system and also evaluated by an in-house developed tool estimating achievable dose-volume histograms (DVHs) based on a database of existing treatment plans. In addition, a clinical implementation scheme for ART is designed and evaluated using clinical cases for its dosimetric qualities and efficiency.
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Graf R, Boehmer D, Budach V, Wust P. Residual translational and rotational errors after kV X-ray image-guided correction of prostate location using implanted fiducials. Strahlenther Onkol 2010; 186:544-50. [PMID: 20936461 DOI: 10.1007/s00066-010-2030-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2009] [Accepted: 07/19/2010] [Indexed: 12/25/2022]
Abstract
PURPOSE To evaluate the residual errors and required safety margins after stereoscopic kilovoltage (kV) X-ray target localization of the prostate in image-guided radiotherapy (IGRT) using internal fiducials. PATIENTS AND METHODS Radiopaque fiducial markers (FMs) have been inserted into the prostate in a cohort of 33 patients. The ExacTrac/Novalis Body™ X-ray 6d image acquisition system (BrainLAB AG, Feldkirchen, Germany) was used. Corrections were performed in left-right (LR), anterior-posterior (AP), and superior-inferior (SI) direction. Rotational errors around LR (x-axis), AP (y) and SI (z) have been recorded for the first series of nine patients, and since 2007 for the subsequent 24 patients in addition corrected in each fraction by using the Robotic Tilt Module™ and Varian Exact Couch™. After positioning, a second set of X-ray images was acquired for verification purposes. Residual errors were registered and again corrected. RESULTS Standard deviations (SD) of residual translational random errors in LR, AP, and SI coordinates were 1.3, 1.7, and 2.2 mm. Residual random rotation errors were found for lateral (around x, tilt), vertical (around y, table), and longitudinal (around z, roll) and of 3.2°, 1.8°, and 1.5°. Planning target volume (PTV)-clinical target volume (CTV) margins were calculated in LR, AP, and SI direction to 2.3, 3.0, and 3.7 mm. After a second repositioning, the margins could be reduced to 1.8, 2.1, and 1.8 mm. CONCLUSION On the basis of the residual setup error measurements, the margin required after one to two online X-ray corrections for the patients enrolled in this study would be at minimum 2 mm. The contribution of intrafractional motion to residual random errors has to be evaluated.
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Affiliation(s)
- Reinhold Graf
- Department of Radiation Oncology, Charite - University Medicine Berlin, Campus Virchow-Klinikum, Berlin, Germany
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Bose S, Shukla H, Maltz J. Beam-centric algorithm for pretreatment patient position correction in external beam radiation therapy. Med Phys 2010; 37:2004-16. [PMID: 20527534 DOI: 10.1118/1.3327457] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
PURPOSE In current image guided pretreatment patient position adjustment methods, image registration is used to determine alignment parameters. Since most positioning hardware lacks the full six degrees of freedom (DOF), accuracy is compromised. The authors show that such compromises are often unnecessary when one models the planned treatment beams as part of the adjustment calculation process. The authors present a flexible algorithm for determining optimal realizable adjustments for both step-and-shoot and arc delivery methods. METHODS The beam shape model is based on the polygonal intersection of each beam segment with the plane in pretreatment image volume that passes through machine isocenter perpendicular to the central axis of the beam. Under a virtual six-DOF correction, ideal positions of these polygon vertices are computed. The proposed method determines the couch, gantry, and collimator adjustments that minimize the total mismatch of all vertices over all segments with respect to their ideal positions. Using this geometric error metric as a function of the number of available DOF, the user may select the most desirable correction regime. RESULTS For a simulated treatment plan consisting of three equally weighted coplanar fixed beams, the authors achieve a 7% residual geometric error (with respect to the ideal correction, considered 0% error) by applying gantry rotation as well as translation and isocentric rotation of the couch. For a clinical head-and-neck intensity modulated radiotherapy plan with seven beams and five segments per beam, the corresponding error is 6%. Correction involving only couch translation (typical clinical practice) leads to a much larger 18% mismatch. Clinically significant consequences of more accurate adjustment are apparent in the dose volume histograms of target and critical structures. CONCLUSIONS The algorithm achieves improvements in delivery accuracy using standard delivery hardware without significantly increasing total treatment session duration. It encourages parsimonious utilization of all available DOF. Finally, in certain cases, it obviates the need of a robotic couch having six DOF for the correction of patient displacement and rotations.
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Affiliation(s)
- Supratik Bose
- Oncology Care Systems Group, Siemens Medical Solutions, 4040 Nelson Avenue, Concord, California 94520, USA.
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van Zijtveld M, Dirkx M, Breuers M, Kuipers R, Heijmen B. Evaluation of the 'dose of the day' for IMRT prostate cancer patients derived from portal dose measurements and cone-beam CT. Radiother Oncol 2010; 96:172-7. [PMID: 20580111 DOI: 10.1016/j.radonc.2010.05.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2009] [Revised: 05/07/2010] [Accepted: 05/17/2010] [Indexed: 11/16/2022]
Abstract
PURPOSE High geometrical and dosimetrical accuracies are required for radiotherapy treatments where IMRT is applied in combination with narrow treatment margins in order to minimize dose delivery to normal tissues. As an overall check, we implemented a method for reconstruction of the actually delivered 3D dose distribution to the patient during a treatment fraction, i.e., the 'dose of the day'. In this article results on the clinical evaluation of this concept for a group of IMRT prostate cancer patients are presented. MATERIALS AND METHODS The actual IMRT fluence maps delivered to a patient were derived from measured EPID-images acquired during treatment using a previously described iterative method. In addition, the patient geometry was obtained from in-room acquired cone-beam CT images. For dose calculation, a mapping of the Hounsfield Units from the planning CT was applied. With the fluence maps and the modified cone-beam CT the 'dose of the day' was calculated. The method was validated using phantom measurements and evaluated clinically for 10 prostate cancer patients in 4 or 5 fractions. RESULTS The phantom measurements showed that the delivered dose could be reconstructed within 3%/3mm accuracy. For prostate cancer patients, the isocenter dose agreed within -0.4+/-1.0% (1 SD) with the planned value, while for on average 98.1% of the pixels within the 50% isodose surface the actually delivered dose agreed within 3% or 3mm with the planned dose. For most fractions, the dose coverage of the prostate volume was slightly deteriorated which was caused by small prostate rotations and small inaccuracies in fluence delivery. The dose that was delivered to the rectum remained within the constraints used during planning. However, for two patients a large degrading of the dose delivery was observed in two fractions. For one patient this was related to changes in rectum filling with respect to the planning CT and for the other to large intra-fraction motion during treatment delivery, resulting in mean underdosages of 16% in the prostate volume. CONCLUSIONS A method to accurately assess the 'dose of the day' was evaluated for prostate cancer patients treated with IMRT. To correct for observed dose deviations off-line dose-adaptive strategies will be developed.
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Affiliation(s)
- Mathilda van Zijtveld
- Department of Radiation Oncology, Division of Medical Physics, Erasmus MC-Daniel den Hoed Cancer Center, Rotterdam, The Netherlands
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Noel CE, Santanam L, Olsen JR, Baker KW, Parikh PJ. An automated method for adaptive radiation therapy for prostate cancer patients using continuous fiducial-based tracking. Phys Med Biol 2010; 55:65-82. [PMID: 19949260 DOI: 10.1088/0031-9155/55/1/005] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Electromagnetic tracking technology is primarily used for continuous prostate localization during radiotherapy, but offers potential value for evaluation of dosimetric coverage and adequacy of treatment for dynamic targets. We developed a highly automated method for daily computation of cumulative dosimetric effects of intra- and inter-fraction target motion for prostate cancer patients using fiducial-based electromagnetic tracking. A computer program utilizing real-time tracking data was written to (1) prospectively determine appropriate rotational/translational motion limits for patients treated with continuous isocenter localization; (2) retrospectively analyze dosimetric target coverage after daily treatment, and (3) visualize three-dimensional rotations and translations of the prostate with respect to the planned target volume and dose matrix. We present phantom testing and a patient case to validate and demonstrate the utility of this application. Gamma analysis of planar dose computed by our application demonstrated accuracy within 1%/1 mm. Dose computation of a patient treatment revealed high variation in minimum dose to the prostate (D(min)) over 40 fractions and a drop in the D(min) of approximately 8% between a 5 mm and a 3 mm PTV margin plan. The infrastructure has been created for patient-specific treatment evaluation using continuous tracking data. This application can be used to increase confidence in treatment delivery to targets influenced by motion.
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Affiliation(s)
- C E Noel
- Department of Radiation Oncology, Washington University School of Medicine, 4921 Parkview Place, St Louis, MO 63110, USA
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Strategies for Online Organ Motion Correction for Intensity-Modulated Radiotherapy of Prostate Cancer: Prostate, Rectum, and Bladder Dose Effects. Int J Radiat Oncol Biol Phys 2009; 75:1254-60. [DOI: 10.1016/j.ijrobp.2009.04.034] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2008] [Revised: 04/23/2009] [Accepted: 04/24/2009] [Indexed: 11/20/2022]
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Lerma FA, Liu B, Wang Z, Yi B, Amin P, Liu S, Feng Y, Yu CX. Role of image-guided patient repositioning and online planning in localized prostate cancer IMRT. Radiother Oncol 2009; 93:18-24. [DOI: 10.1016/j.radonc.2009.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 05/27/2009] [Accepted: 06/08/2009] [Indexed: 01/23/2023]
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Lips IM, van der Heide UA, Kotte AN, van Vulpen M, Bel A. Effect of Translational and Rotational Errors on Complex Dose Distributions With Off-Line and On-Line Position Verification. Int J Radiat Oncol Biol Phys 2009; 74:1600-8. [DOI: 10.1016/j.ijrobp.2009.02.056] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2008] [Revised: 02/19/2009] [Accepted: 02/24/2009] [Indexed: 11/30/2022]
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Redpath AT, Wright P, Muren LP. The contribution of on-line correction for rotational organ motion in image-guided radiotherapy of the bladder and prostate. Acta Oncol 2009; 47:1367-72. [PMID: 18661436 DOI: 10.1080/02841860802263232] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
BACKGROUND AND PURPOSE Current IGRT protocols only correct for organ motion through a 3D translational movement of the treatment couch. The aim of this study was to quantify the relative importance of rotational vs. translational corrections in bladder and prostate IGRT. MATERIALS AND METHODS The data available consisted of a set of 9 bladder cancer patients each having a planning CT scan and between 3 and 8 repeat CT scans throughout their treatment course, with the bladder and prostate (for 5 of the 6 male patients) outlined on all scans. An algorithm was written to determine both the optimum translation and rotation angles required to align the repeat CTVs with their planning CTV. Angles considered were those possible through couch roll, rotation and tilt. The optimum shifts and angles were determined as those that minimised the volume of the repeat scan CTV lying outside the volume of the planning CTV. Two different situations were investigated: 1) 3D translation only (3 degrees of freedom (DoF)) and 2) rotation after applying the optimum 3D translation (6 DoF). Those repeat scans where rotation provided the greatest increase in CTV coverage were further investigated by determining the effect of rotation on the size of the treatment margins required and the volume of the resulting PTV. RESULTS For the bladder, the overall average volume percentage (across scans and patients) of the repeat CTV included in the planning scan CTV was increased from 85.7% without IGRT to 89.5 and 90.1% with 3 DoF and 6 DoF, respectively. The corresponding results for the prostate were 79.4, 86.9 and 87.5%. The resulting decrease in treatment margins required was determined for the 3 bladder and 3 prostate situations where including rotation had the largest impact. In 2 of the 6 situations the resulting PTV volume was reduced by approximately 20% when using an isotropic margin, but this reduction was considerably less when the margins were individually optimised. CONCLUSION When treating either the bladder or prostate alone, translational IGRT correction was by far the most important action necessary to ensure alignment of the repeat CTV with the planning CTV.
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Thongphiew D, Wu QJ, Lee WR, Chankong V, Yoo S, McMahon R, Yin FF. Comparison of online IGRT techniques for prostate IMRT treatment: Adaptive vs repositioning correction. Med Phys 2009; 36:1651-62. [DOI: 10.1118/1.3095767] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Gutfeld O, Kretzler AE, Kashani R, Tatro D, Balter JM. Influence of rotations on dose distributions in spinal stereotactic body radiotherapy (SBRT). Int J Radiat Oncol Biol Phys 2009; 73:1596-601. [PMID: 19306757 DOI: 10.1016/j.ijrobp.2008.12.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2008] [Revised: 10/23/2008] [Accepted: 12/08/2008] [Indexed: 10/21/2022]
Abstract
PURPOSE To evaluate the impact of rotational setup errors on dose distribution in spinal stereotactic body radiotherapy (SBRT). METHODS AND MATERIALS Thirty-nine cone beam computed tomography (CBCT) scans from 16 SBRT treatment courses were analyzed. Alignment (including rotation) to the treatment planning computed tomography was performed, followed by translational alignment that reproduced the actual positioning. The planned fluence was then applied to determine the delivered dose to the targets and organs at risk. RESULTS The mean planning target volume (PTV) was 71.01 mL (SD +/- 60.05; range, 22.62-250.65 mL). Prescribed dose (to the 62-82% isodose) was 14-30 Gy in one to six fractions. The average rotational displacements were 0.38 +/- 1.21, 1.12 +/- 1.82, and -0.51 +/- 2.0 degrees with maximal rotations of -4.29, 5.76, and -6.64 degrees along the x (pitch), y (yaw), and z (roll) axes, respectively. PTV coverage changed by an average of -0.07 Gy (SD +/- 0.20 Gy) between the rotated and the original plan, representing 0.92% of prescription dose (SD +/- 2.65%). For the spinal cord, planned with 2-mm expansion to create a planning organ at risk volume (PRV), the difference in minimum dose to the upper 10% of the PRV volume was 0.03 +/- 0.3 Gy (maximum, 0.9 Gy). Other organs at risk saw insignificant changes in dose. CONCLUSIONS PRV expansion generally assures safe treatment delivery in the face of typically encountered rotations. Given the variability of delivered dose within this expansion for certain cases, caution should be taken to properly interpret doses to the cord when considering clinical dose limits.
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Affiliation(s)
- Orit Gutfeld
- Department of Radiation Oncology, University of Michigan, Ann Arbor, MI 48109-5010, USA
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Fu W, Yang Y, Yue NJ, Heron DE, Huq MS. A cone beam CT-guided online plan modification technique to correct interfractional anatomic changes for prostate cancer IMRT treatment. Phys Med Biol 2009; 54:1691-703. [DOI: 10.1088/0031-9155/54/6/019] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Boda-Heggemann J, Köhler FM, Wertz H, Ehmann M, Hermann B, Riesenacker N, Küpper B, Lohr F, Wenz F. Intrafraction motion of the prostate during an IMRT session: a fiducial-based 3D measurement with Cone-beam CT. Radiat Oncol 2008; 3:37. [PMID: 18986517 PMCID: PMC2588616 DOI: 10.1186/1748-717x-3-37] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Accepted: 11/05/2008] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Image-guidance systems allow accurate interfractional repositioning of IMRT treatments, however, these may require up to 15 minutes. Therefore intrafraction motion might have an impact on treatment precision. 3D geometric data regarding intrafraction prostate motion are rare; we therefore assessed its magnitude with pre- and post-treatment fiducial-based imaging with cone-beam-CT (CBCT). METHODS 39 IMRT fractions in 5 prostate cancer patients after 125I-seed implantation were evaluated. Patient position was corrected based on the 125I-seeds after pre-treatment CBCT. Immediately after treatment delivery, a second CBCT was performed. Differences in bone- and fiducial position were measured by seed-based grey-value matching. RESULTS Fraction time was 13.6 +/- 1.6 minutes. Median overall displacement vector length of 125I-seeds was 3 mm (M = 3 mm, Sigma = 0.9 mm, sigma = 1.7 mm; M: group systematic error, Sigma: SD of systematic error, sigma: SD of random error). Median displacement vector of bony structures was 1.84 mm (M = 2.9 mm, Sigma = 1 mm, sigma = 3.2 mm). Median displacement vector length of the prostate relative to bony structures was 1.9 mm (M = 3 mm, Sigma = 1.3 mm, sigma = 2.6 mm). CONCLUSION a) Overall displacement vector length during an IMRT session is < 3 mm.b) Positioning devices reducing intrafraction bony displacements can further reduce overall intrafraction motion.c) Intrafraction prostate motion relative to bony structures is < 2 mm and may be further reduced by institutional protocols and reduction of IMRT duration.
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Affiliation(s)
- Judit Boda-Heggemann
- Department of Radiation Oncology, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany
| | - Frederick Marc Köhler
- Department of Radiation Oncology, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany
| | - Hansjörg Wertz
- Department of Radiation Oncology, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany
| | - Michael Ehmann
- Department of Radiation Oncology, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany
| | - Brigitte Hermann
- Department of Radiation Oncology, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany
| | - Nadja Riesenacker
- Department of Radiation Oncology, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany
| | - Beate Küpper
- Department of Radiation Oncology, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany
| | - Frank Lohr
- Department of Radiation Oncology, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany
| | - Frederik Wenz
- Department of Radiation Oncology, University Medical Center Mannheim, Theodor-Kutzer-Ufer 1-3, Mannheim, Germany
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van Herten YR, van de Kamer JB, van Wieringen N, Pieters BR, Bel A. Dosimetric evaluation of prostate rotations and their correction by couch rotations. Radiother Oncol 2008; 88:156-62. [DOI: 10.1016/j.radonc.2008.03.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2007] [Revised: 03/14/2008] [Accepted: 03/16/2008] [Indexed: 11/25/2022]
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Abstract
To account for geometric uncertainties during radiotherapy, safety margins are applied. In many cases, these margins overlap organs at risk, thereby limiting dose escalation. The aim of image-guided radiotherapy is to improve the accuracy by imaging tumors and critical structures on the machine just before irradiation. The availability of high-quality imaging systems and automatic image registration on the machine leads to many new clinical applications, such as high-precision hypofractionated treatments of brain metastases and solitary long tumors with online tumor position corrections. In this review, the prerequisites for image guidance in terms of planning, image acquisition, and processing are first described. Then, the various methods of correction are discussed such as table shifts and rotation and direct adaptation of machine parameters. Then, online, offline, and intrafraction correction strategies are discussed. Finally, some imaging dose issues are discussed showing that kilovoltage cone-beam computed tomography guidance has a net positive impact on the integral dose; the gain caused by margin reduction is larger than the image dose. We can conclude that image-guided radiotherapy is very much a clinical reality and that the development of optimal clinical protocols should currently be the focus of research.
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Affiliation(s)
- Marcel van Herk
- Radiotherapy Department, The Netherlands Cancer Institute/Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands.
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