An optimization model and solution for radiation shielding design of radiotherapy treatment vaults

Newman, Francis; Asadi–Zeydabadi, Masoud

doi:10.1118/1.2818955

Cited by 9 publications

(4 citation statements)

References 4 publications

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“…The total weekly dose equivalent at the external maze entrance is equal to the sum of all contributions from leakage, scattered radiation, neutron capture gamma rays and neutrons [13][14][15][16]21].…”

Section: Shielding Calculationsmentioning

confidence: 99%

A versatile program for the calculation of linear accelerator room shielding

2018

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This work aims at designing a computer program to calculate the necessary amount of shielding for a given or proposed linear accelerator room design in radiotherapy. The program (Shield Calculation in Radiotherapy, SCR) has been developed using Microsoft Visual Basic. It applies the treatment room shielding calculations of NCRP report no. 151 to calculate proper shielding thicknesses for a given linear accelerator treatment room design. The program is composed of six main user-friendly interfaces. The first enables the user to upload their choice of treatment room design and to measure the distances required for shielding calculations. The second interface enables the user to calculate the primary barrier thickness in case of three-dimensional conventional radiotherapy (3D-CRT), intensity modulated radiotherapy (IMRT) and total body irradiation (TBI). The third interface calculates the required secondary barrier thickness due to both scattered and leakage radiation. The fourth and fifth interfaces provide a means to calculate the photon dose equivalent for low and high energy radiation, respectively, in door and maze areas. The sixth interface enables the user to calculate the skyshine radiation for photons and neutrons. The SCR program has been successfully validated, precisely reproducing all of the calculated examples presented in NCRP report no. 151 in a simple and fast manner. Moreover, it easily performed the same calculations for a test design that was also calculated manually, and produced the same results. The program includes a new and important feature that is the ability to calculate required treatment room thickness in case of IMRT and TBI. It is characterised by simplicity, precision, data saving, printing and retrieval, in addition to providing a means for uploading and testing any proposed treatment room shielding design. The SCR program provides comprehensive, simple, fast and accurate room shielding calculations in radiotherapy.

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Section: Shielding Calculationsmentioning

confidence: 99%

A versatile program for the calculation of linear accelerator room shielding

2018

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“…These models are discussed in Section 4. Deviation problems are also used for image alignment and comparison [48], and have also been used for vault design [37].…”

Section: -Normmentioning

confidence: 99%

Operations Research Methods for Optimization in Radiation Oncology

Ehrgott

Holder

2017

J Radiat Oncol Inform

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Operations Research has a successful tradition of applying mathematical analysis to a wide range of applications, and problems in Medical Physics have been popular over the last couple of decades. The original application was in the optimal design of the uence map for a radiotherapy treatment, a problem that has continued to receive attention. However, Operations Research has been applied to other clinical problems like patient scheduling, vault design, and image alignment. The overriding theme of this article is to present how techniques in Operations Research apply to clinical problems, which we accomplish in three parts. First, we present the perspective from which an operations researcher addresses a clinical problem. Second, we succinctly introduce the underlying methods that are used to optimize a system, and third, we demonstrate how modern software facilitates problem design. Our discussion is supported by several publications to foster continued study. With numerous clinical, medical, and managerial decisions associated with a clinic, operations research has a promising future at improving how radiotherapy treatments are designed and delivered.

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“…Conventional radiotherapy site planning methods by the National Council on Radiation Protection and Measurements (NCRP) 3 have been incorporated in such optimization problems for linear accelerators. 4 The NCRP shielding design equations are, however, difficult to adapt to the LGK because of its many sources and anisotropic field. Iteratively running MC simulations with different shielding thicknesses in a shielding optimization has been done for nuclear facilities 5,6 but is time-consuming.…”

Section: Introductionmentioning

confidence: 99%

A dose calculation algorithm for radiosurgery treatment room shielding optimization

2023

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Background: Methods described in the literature for designing shielding for treatment rooms for radiotherapy systems often involve assumptions that lead to overestimations of the wall thicknesses required to meet dose rate constraints outside the room. The Leksell Gamma Knife (LGK) has built-in shielding that results in primarily scattered photons leaking into the room. The field of leakage radiation, therefore, has a wide spectrum of energies, up to the primary energies of cobalt-60, and is highly anisotropic, making standard site planning methods difficult to adapt to the LGK. Monte Carlo (MC) simulations are an alternative for dose calculations but are computationally expensive. Purpose: The aim was to develop a dose calculation algorithm for fast estimations of dose rates outside the barriers of a treatment room. The algorithm could then be employed in iterative methods to optimize treatment room parameters such as wall thicknesses and position of the LKG unit. Methods: The algorithm uses pre-calculated MC simulation data in two steps. First, it uses phase spaces that describe single photons in the radiation field around the LGK. Using each photon's position and direction, they are raytraced to the outside of the room. Based on their energy, angle of incidence to the barrier, and the barrier's thickness, a depth-dose profile is sampled from a precalculated library of profiles. The contribution from each photon is added to the space outside the barriers, giving the total dose distribution. The barrier thicknesses are optimized by iteratively running the algorithm and finding the minimum thickness required to keep the resulting maximum dose rate outside below a given upper limit. Results: Comparisons between dose distributions from the dose algorithm and full MC simulations of two typical rooms show good agreement, with the maximum dose rate outside each barrier being estimated within what represents a 2 cm error in concrete barrier thickness. The algorithm is successfully used in optimizing the barrier thicknesses and the results show potential decreases in most barriers' thickness, compared to a conventional method. Conclusions: The algorithm is a promising alternative to conventional barrier design methods, eliminating several shortcomings of the latter whilst being significantly faster than a full MC simulation. The flexibility of the algorithm would further enable solving more complex cases, such as optimizing the LGK position or barrier material to further reduce material use and cost. K E Y W O R D S dose algorithm, gamma knife, shielding optimization 3852

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An optimization model and solution for radiation shielding design of radiotherapy treatment vaults

Cited by 9 publications

References 4 publications

A versatile program for the calculation of linear accelerator room shielding

A versatile program for the calculation of linear accelerator room shielding

Operations Research Methods for Optimization in Radiation Oncology

A dose calculation algorithm for radiosurgery treatment room shielding optimization

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