Technical Note: Fabricating Cerrobend grids with 3D printing for spatially modulated radiation therapy: A feasibility study

Zhu, Xiaofeng; Driewer, J; Li, Sicong; Verma, Vivek; Yu, Long-Chuan; Zhang, Mutian; Zheng, Dandan; Cullip, T; Chang, S; Wang, Andrew Z.; Zhou, Sumin; Enke, Charles Arthur

doi:10.1118/1.4932223

Cited by 10 publications

(16 citation statements)

References 28 publications

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“…Finally, the penumbra values (measured as the lateral distance between 80% and 20% of the maximum dose) were evaluated, with values of 0.19 ± 0.05 cm at 2‐cm‐depth and of 0.22 ± 0.07 cm at 10‐cm‐depth. These values are lower than those reported in previous studies of standard Grid Therapy with values of around 0.24 cm at 1.5‐cm‐depth and of 0.4 cm at 10‐cm‐depth . These penumbra values are smaller than those in clinical radiosurgery (0.3–0.5 cm), which could benefit the sparing of delicate adjacent structures.…”

Section: Resultscontrasting

confidence: 64%

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Dose evaluation of Grid Therapy using a 6 MV flattening filter‐free (FFF) photon beam: A Monte Carlo study

2017

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Section: Resultscontrasting

confidence: 64%

“…The collimator consisted of a 10‐cm‐thick single cerrobend (lead alloy) block. This type of collimators have been commonly used in Grid Therapy . The cerrobend block was preferred over the multileaf collimators to reduce surface dose and delivery time by 80% …”

Section: Methodsmentioning

confidence: 99%

Dose evaluation of Grid Therapy using a 6 MV flattening filter‐free (FFF) photon beam: A Monte Carlo study

2017

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“…There are alternative 3-dimensional printing methods for producing the shields, such as pouring molten lead or Cerrobend into a 3-dimensional printed mold. 30 Stereolithography is excellent for producing high-quality molds and can easily accommodate hot Cerrobend. A mold for a face mask would be printed as 2 or 3 pieces.…”

Section: Discussionmentioning

confidence: 99%

Low-cost optical scanner and 3-dimensional printing technology to create lead shielding for radiation therapy of facial skin cancer: First clinical case series

Sharma

Sasaki

Rickey

et al. 2018

Advances in Radiation Oncology

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PurposeThree-dimensional printing has been implemented at our institution to create customized treatment accessories, including lead shields used during radiation therapy for facial skin cancer. To effectively use 3-dimensional printing, the topography of the patient must first be acquired. We evaluated a low-cost, structured-light, 3-dimensional, optical scanner to assess the clinical viability of this technology.Methods and materialsFor ease of use, the scanner was mounted to a simple gantry that guided its motion and maintained an optimum distance between the scanner and the object. To characterize the spatial accuracy of the scanner, we used a geometric phantom and an anthropomorphic head phantom. The geometric phantom was machined from plastic and included hemispherical and tetrahedral protrusions that were roughly the dimensions of an average forehead and nose, respectively. Polygon meshes acquired by the optical scanner were compared with meshes generated from high-resolution computed tomography images. Most optical scans contained minor artifacts. Using an algorithm that calculated the distances between the 2 meshes, we found that most of the optical scanner measurements agreed with those from the computed tomography scanner within approximately 1 mm for the geometric phantom and approximately 2 mm for the head phantom. We used this optical scanner along with 3-dimensional printer technology to create custom lead shields for 10 patients receiving orthovoltage treatments of nonmelanoma skin cancers of the face. Patient, tumor, and treatment data were documented.ResultsLead shields created using this approach were accurate, fitting the contours of each patient's face. This process added to patient convenience and addressed potential claustrophobia and medical inability to lie supine.ConclusionsThe scanner was found to be clinically acceptable, and we suggest that the use of an optical scanner and 3-dimensional printer technology become the new standard of care to generate lead shielding for orthovoltage radiation therapy of nonmelanoma facial skin cancer.

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“…[ 6 ] While some publications have discussed different methods of fabricating Grid blocks. [ 7 8 ] Almendral et al . [ 7 ] introduced a simple method to construct a hybrid Grid pattern using both block and multileaf collimator (MLC).…”

Section: Introductionmentioning

confidence: 99%

“…Zhu et al . [ 8 ] investigated the feasibility of fabricating Cerrobend Grid block using 3D printing. Recently, new advancements of technologies such as Tomotherapy and Cyberknife were used for a virtual Grid therapy.…”

Section: Introductionmentioning

confidence: 99%

Grid block design based on monte carlo simulated dosimetry, the linear quadratic and Hug–Kellerer radiobiological models

et al. 2017

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Purpose:The clinical efficacy of Grid therapy has been examined by several investigators. In this project, the hole diameter and hole spacing in Grid blocks were examined to determine the optimum parameters that give a therapeutic advantage.Methods:The evaluations were performed using Monte Carlo (MC) simulation and commonly used radiobiological models. The Geant4 MC code was used to simulate the dose distributions for 25 different Grid blocks with different hole diameters and center-to-center spacing. The therapeutic parameters of these blocks, namely, the therapeutic ratio (TR) and geometrical sparing factor (GSF) were calculated using two different radiobiological models, including the linear quadratic and Hug–Kellerer models. In addition, the ratio of the open to blocked area (ROTBA) is also used as a geometrical parameter for each block design. Comparisons of the TR, GSF, and ROTBA for all of the blocks were used to derive the parameters for an optimum Grid block with the maximum TR, minimum GSF, and optimal ROTBA. A sample of the optimum Grid block was fabricated at our institution. Dosimetric characteristics of this Grid block were measured using an ionization chamber in water phantom, Gafchromic film, and thermoluminescent dosimeters in Solid Water™ phantom materials.Results:The results of these investigations indicated that Grid blocks with hole diameters between 1.00 and 1.25 cm and spacing of 1.7 or 1.8 cm have optimal therapeutic parameters (TR > 1.3 and GSF~0.90). The measured dosimetric characteristics of the optimum Grid blocks including dose profiles, percentage depth dose, dose output factor (cGy/MU), and valley-to-peak ratio were in good agreement (±5%) with the simulated data.Conclusion:In summary, using MC-based dosimetry, two radiobiological models, and previously published clinical data, we have introduced a method to design a Grid block with optimum therapeutic response. The simulated data were reproduced by experimental data.

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Technical Note: Fabricating Cerrobend grids with 3D printing for spatially modulated radiation therapy: A feasibility study

Abstract: This study demonstrates that it is feasible to implement 3D printing technique in applying grid therapy in clinic.

Cited by 10 publications

References 28 publications

Dose evaluation of Grid Therapy using a 6 MV flattening filter‐free (FFF) photon beam: A Monte Carlo study

Dose evaluation of Grid Therapy using a 6 MV flattening filter‐free (FFF) photon beam: A Monte Carlo study

Low-cost optical scanner and 3-dimensional printing technology to create lead shielding for radiation therapy of facial skin cancer: First clinical case series

Grid block design based on monte carlo simulated dosimetry, the linear quadratic and Hug–Kellerer radiobiological models

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