An Investigation into the Couch Coefficient Accuracy of Exact IGRT Couch with Eclipse Treatment Planning System in Vital Beam Varian Linear Accelerator
-
Mahya Badrasa
,
Mojan Mobaraki
,
Abolfazl Nickfarjam
,
Mohammad Hasan Larizadeh
,
Nasim Namiranian
,
Nima Hamzian
Abstract
Purpose: Posterior oblique beams are increasingly common in radiotherapy techniques. Radiation beams traversing through the treatment couch would be attenuated and cause under-dosage in the tumor region. The attenuation of an IGRT carbon fiber Couch for different angles, energies, field sizes, measurement points, couch regions, and the ability of the Eclipse treatment planning system to predict doses were investigated.
Materials and Methods: The Varian Vital Beam linear accelerator (Varian Medical Systems) and the Exact IGRT couch top, a new device for patient positioning, were utilized. The couch coefficient was calculated using in-air gantry angle measurements to determine the most attenuation angle. the attenuation measurements were performed in three measurement points of an inhomogeneous PMMA phantom using a farmer ionization chamber for three energies with six field sizes in three regions of an IGRT couch at the most attenuation gantry angle.
Results: The results of the couch coefficient measurements demonstrated that in three regions of the IGRT couch at an angle of 130˚, the photon beam was most attenuated. The difference between the calculated dose by the Eclipse treatment planning system and the experimental dose measurements was 1.855%. The difference is less than 3% and the attenuation was within the allowable range for treatment.
Conclusion: The IGRT treatment couch in posterior oblique gantry angles decreased the dose in the measurement points due to gantry angle, field size, energy, and couch region. The Eclipse treatment planning system can sufficiently predict the tumor dose distribution.
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2- W Kenji Myint, Malgorzata Niedbala, David Wilkins, and Lee H Gerig, "Investigating treatment dose error due to beam attenuation by a carbon fiber tabletop." Journal of applied clinical medical physics, Vol. 7 (No. 3), pp. 21-27, (2006).
3- SC Sharma and MW Johnson, "Photon beam attenuation for a patient support assembly during arc therapy for a medical linear accelerator." Medical dosimetry, Vol. 17 (No. 4), pp. 225-28, (1992).
4- Jürgen Meyer, John A Mills, Olivier CL Haas, Keith J Burnham, and Elizabeth M Parvin, "Accommodation of couch constraints for coplanar intensity modulated radiation therapy." Radiotherapy and Oncology, Vol. 61 (No. 1), pp. 23-32, (2001).
5- Heng Li, Andrew K Lee, Jennifer L Johnson, Ronald X Zhu, and Rajat J Kudchadker, "Characterization of dose impact on IMRT and VMAT from couch attenuation for two Varian couches." Journal of applied clinical medical physics, Vol. 12 (No. 3), pp. 23-31, (2011).
6- Zhihui Hu, Jianrong Dai, Liang Li, Yin Cao, Yixin Song, and Guishan Fu, "Evaluating and modeling of photon beam attenuation by a standard treatment couch." Journal of applied clinical medical physics, Vol. 12 (No. 4), pp. 139-46, (2011).
7- Kiley B Pulliam, Rebecca M Howell, David Followill, Dershan Luo, R Allen White, and Stephen F Kry, "The clinical impact of the couch top and rails on IMRT and arc therapy." Physics in Medicine & Biology, Vol. 56 (No. 23), p. 7435, (2011).
8- Jan KH Seppälä and Jarmo AJ Kulmala, "Increased beam attenuation and surface dose by different couch inserts of treatment tables used in megavoltage radiotherapy." Journal of applied clinical medical physics, Vol. 12 (No. 4), pp. 15-23, (2011).
9- Sameer Rafla and Fikry Meleka, "Problems of posterior fields." Radiology, Vol. 117 (No. 1), pp. 224-24, (1975).
10- G Krithivas and SN Rao, "Arc therapy dose perturbation due to the center bar in a clinic 4/100 couch assembly." Medical dosimetry, Vol. 13 (No. 1), pp. 15-18, (1988).
11- LH Gerig, M Niedbala, and BJ Nyiri, "Dose perturbations by two carbon fiber treatment couches and the ability of a commercial treatment planning system to predict these effects." Medical physics, Vol. 37 (No. 1), pp. 322-28, (2010).
12- Paul A Jursinic, Renu Sharma, and Jim Reuter, "MapCHECK used for rotational IMRT measurements: step‐and‐shoot, TomoTherapy, RapidArc." Medical physics, Vol. 37 (No. 6Part1), pp. 2837-46, (2010).
13- Christopher F Njeh, Jason Parker, Joseph Spurgin, and Elizabeth Rhoe, "A validation of carbon fiber imaging couch top modeling in two radiation therapy treatment planning systems: Philips Pinnacle 3 and BrainLAB iPlan RT Dose." Radiation Oncology, Vol. 7pp. 1-11, (2012).
14- Ellen D Yorke, "The geometry of avoiding beam intersections and blocking tray collisions." Medical physics, Vol. 16 (No. 2), pp. 288-91, (1989).
15- Sandra C Vieira, Robert SJP Kaatee, Maarten LP Dirkx, and Ben JM Heijmen, "Two‐dimensional measurement of photon beam attenuation by the treatment couch and immobilization devices using an electronic portal imaging device." Medical physics, Vol. 30 (No. 11), pp. 2981-87, (2003).
16- Björn Poppe et al., "The effect of a carbon-fiber couch on the depth-dose curves and transmission properties for megavoltage photon beams." Strahlentherapie und Onkologie, Vol. 183 (No. 1), p. 43, (2007).
17- Stephen McCormack, Jennifer Diffey, and Andrew Morgan, "The effect of gantry angle on megavoltage photon beam attenuation by a carbon fiber couch insert." Medical physics, Vol. 32 (No. 2), pp. 483-87, (2005).
18- Bie De Ost, Jo Vanregemorter, Bob Schaeken, and Danielle Van den Weyngaert, "The effect of carbon fibre inserts on the build-up and attenuation of high energy photon beams." Radiotherapy and Oncology, Vol. 45 (No. 3), pp. 275-77, (1997).
19- Christopher F Njeh, Timothy W Raines, and Mark W Saunders, "Determination of the photon beam attenuation by the Brainlab imaging couch: angular and field size dependence." Journal of applied clinical medical physics, Vol. 10 (No. 3), pp. 16-27, (2009).
20- RK Munjal, PS Negi, AG Babu, SN Sinha, AK Anand, and T Kataria, "Impact of 6MV photon beam attenuation by carbon fiber couch and immobilization devices in IMRT planning and dose delivery." Journal of Medical Physics/Association of Medical Physicists of India, Vol. 31 (No. 2), p. 67, (2006).
21- Tülay P Meydanci and Gönül Kemikler, "Effect of a carbon fiber tabletop on the surface dose and attenuation for high-energy photon beams." Radiation medicine, Vol. 26pp. 539-44, (2008).
22- Ali Sid Ahmed M Ali, Maarten LP Dirkx, Marcel GJ Breuers, and Ben JM Heijmen, "Inclusion of the treatment couch in Portal dose image prediction for high precision EPID dosimetry." Medical physics, Vol. 38 (No. 1), pp. 377-81, (2011).
23- IB Mihaylov, P Corry, Y Yan, V Ratanatharathorn, and EG Moros, "Modeling of carbon fiber couch attenuation properties with a commercial treatment planning system." Medical physics, Vol. 35 (No. 11), pp. 4982-88, (2008).
24- Emiliano Spezi and Andrea Ferri, "Dosimetric characteristics of the Siemens IGRT carbon fiber tabletop." Medical dosimetry, Vol. 32 (No. 4), pp. 295-98, (2007).
25- Eugenio Vanetti, Giorgia Nicolini, Alessandro Clivio, Antonella Fogliata, and Luca Cozzi, "The impact of treatment couch modelling on RapidArc." Physics in Medicine & Biology, Vol. 54 (No. 9), p. N157, (2009).
26- Vance P Keeling, Salahuddin Ahmad, and Hosang Jin, "A comprehensive comparison study of three different planar IMRT QA techniques using MapCHECK 2." Journal of applied clinical medical physics, Vol. 14 (No. 6), pp. 222-33, (2013).
2- W Kenji Myint, Malgorzata Niedbala, David Wilkins, and Lee H Gerig, "Investigating treatment dose error due to beam attenuation by a carbon fiber tabletop." Journal of applied clinical medical physics, Vol. 7 (No. 3), pp. 21-27, (2006).
3- SC Sharma and MW Johnson, "Photon beam attenuation for a patient support assembly during arc therapy for a medical linear accelerator." Medical dosimetry, Vol. 17 (No. 4), pp. 225-28, (1992).
4- Jürgen Meyer, John A Mills, Olivier CL Haas, Keith J Burnham, and Elizabeth M Parvin, "Accommodation of couch constraints for coplanar intensity modulated radiation therapy." Radiotherapy and Oncology, Vol. 61 (No. 1), pp. 23-32, (2001).
5- Heng Li, Andrew K Lee, Jennifer L Johnson, Ronald X Zhu, and Rajat J Kudchadker, "Characterization of dose impact on IMRT and VMAT from couch attenuation for two Varian couches." Journal of applied clinical medical physics, Vol. 12 (No. 3), pp. 23-31, (2011).
6- Zhihui Hu, Jianrong Dai, Liang Li, Yin Cao, Yixin Song, and Guishan Fu, "Evaluating and modeling of photon beam attenuation by a standard treatment couch." Journal of applied clinical medical physics, Vol. 12 (No. 4), pp. 139-46, (2011).
7- Kiley B Pulliam, Rebecca M Howell, David Followill, Dershan Luo, R Allen White, and Stephen F Kry, "The clinical impact of the couch top and rails on IMRT and arc therapy." Physics in Medicine & Biology, Vol. 56 (No. 23), p. 7435, (2011).
8- Jan KH Seppälä and Jarmo AJ Kulmala, "Increased beam attenuation and surface dose by different couch inserts of treatment tables used in megavoltage radiotherapy." Journal of applied clinical medical physics, Vol. 12 (No. 4), pp. 15-23, (2011).
9- Sameer Rafla and Fikry Meleka, "Problems of posterior fields." Radiology, Vol. 117 (No. 1), pp. 224-24, (1975).
10- G Krithivas and SN Rao, "Arc therapy dose perturbation due to the center bar in a clinic 4/100 couch assembly." Medical dosimetry, Vol. 13 (No. 1), pp. 15-18, (1988).
11- LH Gerig, M Niedbala, and BJ Nyiri, "Dose perturbations by two carbon fiber treatment couches and the ability of a commercial treatment planning system to predict these effects." Medical physics, Vol. 37 (No. 1), pp. 322-28, (2010).
12- Paul A Jursinic, Renu Sharma, and Jim Reuter, "MapCHECK used for rotational IMRT measurements: step‐and‐shoot, TomoTherapy, RapidArc." Medical physics, Vol. 37 (No. 6Part1), pp. 2837-46, (2010).
13- Christopher F Njeh, Jason Parker, Joseph Spurgin, and Elizabeth Rhoe, "A validation of carbon fiber imaging couch top modeling in two radiation therapy treatment planning systems: Philips Pinnacle 3 and BrainLAB iPlan RT Dose." Radiation Oncology, Vol. 7pp. 1-11, (2012).
14- Ellen D Yorke, "The geometry of avoiding beam intersections and blocking tray collisions." Medical physics, Vol. 16 (No. 2), pp. 288-91, (1989).
15- Sandra C Vieira, Robert SJP Kaatee, Maarten LP Dirkx, and Ben JM Heijmen, "Two‐dimensional measurement of photon beam attenuation by the treatment couch and immobilization devices using an electronic portal imaging device." Medical physics, Vol. 30 (No. 11), pp. 2981-87, (2003).
16- Björn Poppe et al., "The effect of a carbon-fiber couch on the depth-dose curves and transmission properties for megavoltage photon beams." Strahlentherapie und Onkologie, Vol. 183 (No. 1), p. 43, (2007).
17- Stephen McCormack, Jennifer Diffey, and Andrew Morgan, "The effect of gantry angle on megavoltage photon beam attenuation by a carbon fiber couch insert." Medical physics, Vol. 32 (No. 2), pp. 483-87, (2005).
18- Bie De Ost, Jo Vanregemorter, Bob Schaeken, and Danielle Van den Weyngaert, "The effect of carbon fibre inserts on the build-up and attenuation of high energy photon beams." Radiotherapy and Oncology, Vol. 45 (No. 3), pp. 275-77, (1997).
19- Christopher F Njeh, Timothy W Raines, and Mark W Saunders, "Determination of the photon beam attenuation by the Brainlab imaging couch: angular and field size dependence." Journal of applied clinical medical physics, Vol. 10 (No. 3), pp. 16-27, (2009).
20- RK Munjal, PS Negi, AG Babu, SN Sinha, AK Anand, and T Kataria, "Impact of 6MV photon beam attenuation by carbon fiber couch and immobilization devices in IMRT planning and dose delivery." Journal of Medical Physics/Association of Medical Physicists of India, Vol. 31 (No. 2), p. 67, (2006).
21- Tülay P Meydanci and Gönül Kemikler, "Effect of a carbon fiber tabletop on the surface dose and attenuation for high-energy photon beams." Radiation medicine, Vol. 26pp. 539-44, (2008).
22- Ali Sid Ahmed M Ali, Maarten LP Dirkx, Marcel GJ Breuers, and Ben JM Heijmen, "Inclusion of the treatment couch in Portal dose image prediction for high precision EPID dosimetry." Medical physics, Vol. 38 (No. 1), pp. 377-81, (2011).
23- IB Mihaylov, P Corry, Y Yan, V Ratanatharathorn, and EG Moros, "Modeling of carbon fiber couch attenuation properties with a commercial treatment planning system." Medical physics, Vol. 35 (No. 11), pp. 4982-88, (2008).
24- Emiliano Spezi and Andrea Ferri, "Dosimetric characteristics of the Siemens IGRT carbon fiber tabletop." Medical dosimetry, Vol. 32 (No. 4), pp. 295-98, (2007).
25- Eugenio Vanetti, Giorgia Nicolini, Alessandro Clivio, Antonella Fogliata, and Luca Cozzi, "The impact of treatment couch modelling on RapidArc." Physics in Medicine & Biology, Vol. 54 (No. 9), p. N157, (2009).
26- Vance P Keeling, Salahuddin Ahmad, and Hosang Jin, "A comprehensive comparison study of three different planar IMRT QA techniques using MapCHECK 2." Journal of applied clinical medical physics, Vol. 14 (No. 6), pp. 222-33, (2013).
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| Issue | Vol 13 No 3 (2026) | |
| Section | Original Article(s) | |
| DOI | https://doi.org/10.18502/fbt.v13i3.22740 | |
| Keywords | ||
| Radiotherapy Treatment Couch Exact Image-Guided Radiation Therapy Couch Attenuation Eclipse Treatment Planning System | ||
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How to Cite
1.
Badrasa M, Mobaraki M, Nickfarjam A, Larizadeh MH, Namiranian N, Hamzian N. An Investigation into the Couch Coefficient Accuracy of Exact IGRT Couch with Eclipse Treatment Planning System in Vital Beam Varian Linear Accelerator. Frontiers Biomed Technol. 2026;13(3):676-686.
