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Session: Space-time Modulation of Treatment [Return to Session]

A Novel Method for Placing Lattice Targets for Spatially Fractionated Stereotactic Body Radiation Therapy (SFSBRT)

L Buchanan2*, P Keigwin1, M Kaluarachchi2, M Schwer3, G Cardarelli4, (1) University of Rhode Island, Department of Physics, Kingston, RI, (2) Rhode Island Hospital/ Warren Alpert Medical, Providence, RI, (3) Rhode Island Hospital / Warren Alpert Medical, Warwick, RI, (4) Rhode Island Hospital / Warren Alpert Medical, Providence, RI


TU-G-BRA-1 (Tuesday, 7/12/2022) 1:45 PM - 2:45 PM [Eastern Time (GMT-4)]

Ballroom A

Purpose: Spatially Fractionated Radiation Therapy (SFRT) has shown promising results for the treatment of large and/or radio resistant tumors. The two main ways to implement this type of treatment are by using a traditional solid grid applicator or the multi-leaf collimator (MLC) within the linear accelerator. Recent studies have used this technique to deliver a SBRT plan while irradiating the spheres to a simultaneous integrated boost (SIB).. The placement of these spheres is difficult and time consuming. This investigation was performed to validate a novel and practical scripting process to accentuate a volumetric modulated arc therapy (VMAT) planning method for Biology Spatial Fractionated SBRT (LATTICE) by using the scripting capability in Raystation on previously treated bulky tumors anonymized for protection of information.

Methods: We show a unique scripted algorithm for easily placing the spheres in the PTV following published guidelines by comparing two methods of placing the spheres: manually and through a Raystation script. The manual structures were created using the method described by Duresetti et al.1 The scripting method places spheres 4 cm in axial plans 6 cm diagonal and 3 cm in coronal planes. In addition, a second script can be used to create ring structures around the spheres.

Results: We analyzed five patient data sets, manual and scripted sphere placements. The number of spheres differed by the size and shape of the GTV. In all cases the placement using the manual placement was approximately 1-2 hours. The scripted placement in contrast took only minutes.

Conclusion: We can show that this scripting technique greatly reduces the ominous task of placing sphere correctly in SBRT targets. The script also reduces the chance of spheres being placed outside the GTV in coronal or sagittal planes. This project has decreased the amount of time needed to plan SFRT.


Treatment Planning, Modeling, Radiosurgery


TH- External Beam- Photons: treatment planning/virtual clinical studies

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