Quality assurance of simultaneous treatment of two targets in pelvic region planned with single isocenter using three dimensional conformal radiotherapy (3DCRT) technique

Suman Kumar Putha, Challapalli Srinivas, Vadhiraja Bejadi Manjunath, Arun Kumar Elavunkal Sukumaran, Sridhar Chinthamani, Prakash Saxena, Sourjya Banerjee, Dinesh Pai Kasturi


Purpose: The purpose of this study was to conduct quality assurance of a three dimensional conformal radiotherapy (3DCRT) of two targets in pelvis region planned with single isocenter technique.

Methods: A treatment plan was generated with two identical water phantoms with ionization chamber (IC) sleeves (IC-1 & IC-2), simulated as if targets are in pelvis region, simultaneously irradiated with single isocenter technique with a dose prescription of 300 cGy for point dose verification. A two dimensional ion chamber array detector was used for fluence verification.

Results: Calculated minimum, mean and maximum dose (in cGy) for IC-1 & IC-2 were 295, 303 and 307 as per dose volume histogram. The global dose maximum was found to be 307.4 cGy. Measured point doses to both lesions were within ±2.5% of the computed dose. A pass percentage of 97% was obtained with the set of criteria 3 mm distance to agreement and 3% dose difference for fluence verification.

Conclusion: Treatment execution of two targets simultaneously with single isocenter can reduce positional errors and delivery time.


Quality Assurance; Two Targets; Single Isocenter; Conformal Radiotherapy

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Potter L, Lian J, Morris D, et al. Treating multiple tumors simultaneously with a 4-bank mMLC. Available from http://www.med.unc.edu/radonc/proj/treating-multiple-tumors-simultaneously-with-a-4-bank-mmlc

Luxon G, Jozef G. Luxton G, Jozsef G. Single isocenter treatment planning for homogeneous dose delivery to nonspherical targets in multiarc linear accelerator radiosurgery. Int J Radiat Oncol Biol Phys. 1995;31:635-43.

Clark GM, Popple RA, Young PE, Fiveash JB. Feasibility of single iso-center volumetric modulated arc radiosurgery for treatment of multiple brain metastases. Int J Radiat Oncol Biol Phys. 2010; 73:296-302.

Huang C. Treatment of multiple brain metastases using stereotactic radiosurgery with single isocenter volumetric arc therapy: Comparison with conventional dynamic conformal arc and static beam stereotactic radiosurgery; Master’s thesis submitted to Duke University 2012. Available from http://dukespace.lib.duke.edu/dspace/bitstream/handle/10161/5478/Huang_duke_0066N_11362.pdf?sequence=1

Ebert MA, Zavgorodni SF, Kendric LA, et al. Multi-isocenter stereotactic radiotherapy: implications for target dose distributions of systematic and random localization errors. Int J Radiat Oncol Biol Phys. 2001;51:545-54.

Shrtaus N, Schifter D, Alani S, et al. Stereotactic Treatment of multiple Targets using single Isocenter: Planning, Dosimetric and Deliver advantages. Med Phys. 2011;38: 3395.

VanderSpek L, Wang J, Alksne J, Murphy KT. Single fraction, single isocenter intensity modulated radiosurgery (IMRS) for multiple brain metastases: Dosimetric and early clinical experience. Int J Radiat Oncol Biol Phys. 2007; 69:265.

Marks LB, Sherouse GW, Das S, et al. Conformal radiation therapy with fixed shaped coplanar or non-coplanar radiation beam bouquets: a possible alternative to radiosurgery. Int J Radiat Oncol Biol Phys. 1995;33:1209-19.

Ramani R, O'Brien PF, Davey P, et al. Implementation of multiple isocenter treatment for dynamic radiosurgery. Br J Radiol. 1995; 68:731–5.

Sherouse GW. A mathematical basis for selection of wedge angle and orientation. Med Phys. 1993; 20:1211-8.

Sherouse GW, Bourland JD, Reynolds K, et al. Virtual Simulation in the clinical setting: some practical considerations. Int J Radiat Oncol Biol Phys. 1990; 20:1059-65.

An international code of practice for dosimetry based on absorbed dose to water IAEA Tech. Series No.398, Absorbed dose determination in external beam radiotherapy. International atomic energy agency, Vienna: IAEA; 2000.

Ojala J. The accuracy of the Acuros XB algorithm in external beam radiotherapy – a comprehensive review. Int J Cancer Ther Oncol. 2014; 2:020417.

Rana S, Rogers K, Pokharel S, Cheng C. Evaluation of Acuros XB algorithm based on RTOG 0813 dosimetric criteria for SBRT lung treatment with RapidArc. J Appl Clin Med Phys. 2014; 15:4474.

Rana S. Clinical dosimetric impact of Acuros XB and analytical anisotropic algorithm (AAA) on real lung cancer treatment plans: review. Int J Cancer Ther Oncol. 2014; 2:02019.

Oyewale S. Dose prediction accuracy of collapsed cone convolution superposition algorithm in a multi-layer inhomogenous phantom. Int J Cancer Ther Oncol. 2013; 1:01016

DOI: http://dx.doi.org/10.14319/ijcto.33.15

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