The reused mask application for extremity soft tissue sarcoma immobilization


  • Manatchanok Chitnok Division of Radiotherapy, Department of Radiology, King Chulalongkorn Memorial Hospital
  • Boontarik Nayong Division of Radiotherapy, Department of Radiology, King Chulalongkorn Memorial Hospital
  • Taweap Sanghangthum Division of Radiotherapy, Department of Radiology, Faculty of Medicine, Chulalongkorn University


Reused mask, Immobilization, Extremity, Soft tissue sarcoma


In radiotherapy, the accuracy and reproducibility for patient setup using immobilization is very important. At present, the vacuum styrofoam named Vac-Lok is usually used in case of extremity cancer treatment at department of radiation oncology, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, however, there are some problems of treatment fields drawing on patient’s skin and inconvenience of patient setup with Vac-Lok. Therefore, the purpose of this study was to compare the patient setup accuracy between using Vac-Lok and reused-mask using image guided radiation therapy for extremity soft tissue sarcoma treatment. The data were collected from 6 patients who treated with each immobilization device during April to December 2017. The patients were verified the setup error using daily electronic portal imaging device in AP and lateral directions. The results showed that vertical direction presented the least error in both methods. The patient setup errors using Vac-Lok in vertical, longitudinal and lateral directions were -0.01±0.05, -0.21±0.28 and 0.23±0.47 cm, respectively, while the errors using reused-mask were 0.00±0.03, 0.08±0.30 and -0.14±0.27, respectively. In conclusion, the reused-mask can be applied to immobilize the extremity soft tissue sarcoma cases with the high accuracy and reproducibility and could replace the Vac-Lok. The institutes that have no Vac-Lok are possible to apply the reused-mask to increase the efficiency of extremity soft tissue sarcoma treatment.


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Clark MA, Fisher C, Judson I, Thomas JM. Soft-tissue sarcoma in adults. N Engl J Med. 2005;353(7):701-11.

Folkert MR, Singer S, Brennan MF, Kuk D, Qin LX, et al. Comparison of local recurrence with conventional and Intensity-Modulated Radiation Therapy for primary soft-tissue sarcomas of the extremity. J Clin Oncol. 2014;32(29):3236-41.

Light KL. Immobilization and treatment of patients receiving radiation therapy for extremity soft-tissue sarcoma. Med Dosim. 1992;17(3):135-9.

Dickie CI, Parent A, Griffin A, Catton C, Chung P, et al. A Device and procedure for immobilization of patients receiving limb-preserving radiotherapy for soft tissue sarcoma. Med Dosim. 2009;34(3):243-249.

Gierga DP, Turcotte JC, Tong LW, Chen YNE, DeLaney TF. Analysis of setup uncertainties for extremity sarcoma patients using surface imaging. Prac Rad Oncol. 2014;4(4):261-6.

Cheng KF, Wu VWC. Comparison of the effectiveness of different immobilization systems in different body regions using daily megavoltage CT in helical tomotherapy. Br J Radiol. 2014;87(1034):1-7.



How to Cite

Chitnok ม, Nayong บ, Sanghangthum ท. The reused mask application for extremity soft tissue sarcoma immobilization. Thai J Rad Tech [Internet]. 2018 Dec. 28 [cited 2022 Jul. 1];43(1):1-5. Available from:



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