Assessing the fit of 3D printed bolus from CT, optical scanner and photogrammetry methods

Maxwell, Shawn; Charles, Paul; Cassim, Naasiha; Kairn, Tanya; Crowe, Scott

doi:10.1007/s13246-020-00861-8

Cited by 14 publications

(22 citation statements)

References 15 publications

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“…While the fit of devices produced in this study was assessed by visual inspection, for clinical use, the fit of manufactured devices could be assessed using medical images acquired with the device in situ (e.g. at CT simulation or cone‐beam CT for image guidance), using the air gap method described by Dipasquale et al 2 and Maxwell et al 8 …”

Section: Discussionmentioning

confidence: 99%

“…While these solutions are cost‐effective, they are often not metrology grade (i.e. providing precise measurement of dimensions), requiring concurrent imaging of reference items of known dimensions and producing less accurate reconstructions than commercial surface scanning systems which may manifest in the form of air gaps between patient surfaces and 3D‐printed devices 8 …”

Section: Introductionmentioning

confidence: 99%

“…Purpose‐built optical surface scanning systems, such as stereo depth scanners 13 and structured light scanners, 1,2,6,8 are able to produce precise and accurate models of anatomy, suitable for patient‐matched 3D‐printed devices. Combined with computer‐aided design (CAD) software, simple devices, such as uniform thickness bolus or shields 14 or nose blocks, can be easily created.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of optical 3D scanning system for radiotherapy use

Crowe

Luscombe

Maxwell

et al. 2021

J of Medical Radiation Sci

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Introduction Optical three‐dimensional scanning devices can produce geometrically accurate, high‐resolution models of patients suitable for clinical use. This article describes the use of a metrology‐grade structured light scanner for the design and production of radiotherapy medical devices and synthetic water‐equivalent computer tomography images. Methods Following commissioning of the device by scanning objects of known properties, 173 scans were performed on 26 volunteers, with observations of subjects and operators collected. Results The fit of devices produced using these scans was assessed, and a workflow for the design of complex devices using a treatment planning system was identified. Conclusions Recommendations are provided on the use of the device within a radiation oncology department.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Evaluation of optical 3D scanning system for radiotherapy use

Crowe

Luscombe

Maxwell

et al. 2021

J of Medical Radiation Sci

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“…Absolute scaling of a 3D reconstruction is a limitation of photogrammetry since accurate measurements of an object's known dimensions is required. The impact of scaling on photogrammetry reconstruction accuracy has previously been mentioned in other studies [14,16] and possible future work will look at improving the scaling accuracy.…”

Section: Surface Applicator Evaluationmentioning

confidence: 84%

“…Recent research has evaluated alternative imaging techniques for generating 3D printable patient-speci c devices. These include using non-contact techniques such as 3D scanning technology [12][13][14][15] and optical photogrammetry [14,16]. Photogrammetry is generally described as the science of making reliable measurements from photographs [16].…”

Section: Introductionmentioning

confidence: 99%

A dosimetric comparison of CT- and photogrammetry- generated 3D printed HDR brachytherapy surface applicators

et al. 2022

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In this study, we investigate whether an acceptable dosimetric plan can be obtained for a surface applicator designed using photogrammetry and compare the plan quality to a CT-derived applicator. The nose region of a RANDO anthropomorphic phantom was selected as the treatment site due to its high curvature. Photographs were captured using a Nikon D5600 DSLR camera and reconstructed using Agisoft Metashape while CT data was obtained using a Canon Aquillion scanner. Virtual surface applicators were designed in Blender and printed with ABS plastic. Treatment plans with a prescription dose of 3.85 Gy x 10 fractions with 100 % dose to PTV on the bridge of the nose at 2 mm depth were generated separately using AcurosBV in the Varian BrachyVision TPS. PTV D 98% , D 90% and V 100% , and OAR D 0.1cc , D 2cc and V 50% dose metrics and dwell times were evaluated, with the applicator t assessed by air-gap volume measurements. Both types of surface applicators were printed with minimal defects and visually tted well to the target area. The measured air-gap volume between the photogrammetry applicator and phantom surface was 44 % larger than the CT-designed applicator, with a mean air gap thickness of 3.24 and 2.88 mm, respectively. The largest difference in the dose metric observed for the PTV and OAR was the PTV V 100% of -1.27 % and skin D 0.1cc of -0.28 %. PTV D 98% and D 90% and OAR D 2cc and V 50% for the photogrammetry based plan were all within 0.5 % of the CT based plan. Total dwell times were also within 5 %. A 3D printed surface applicator for the nose was successfully constructed using photogrammetry techniques. Although it produced a larger air gap between the surface applicator and phantom surface, a clinically acceptable dose plan was created with similar PTV and OAR dose metrics to the CT-designed applicator. Additional future work is required to comprehensively evaluate its suitability in a clinically environment.

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An evaluation of consumer smartphones for generating bolus and surface mould applicators for radiation oncology

Bridger,

Caraça Santos,

Reich

et al. 2024

Medical Physics

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BackgroundThe use of Computed Tomography (CT) imaging data to create 3D printable patient‐specific devices for radiation oncology purposes is already well established in the literature and has shown to have superior conformity than conventional methods. Using non‐ionizing radiation imaging techniques such as photogrammetry or laser scanners in‐lieu of a CT scanner presents many desirable benefits including reduced imaging dose and fabrication of the device can be completed prior to simulation. With recent advancements in smartphone‐based technology, photographic and LiDAR‐based technologies are more readily available than ever before and to a high level of quality. As a result, these non‐ionizing radiation imaging methods are now able to generate patient‐specific devices that can be acceptable for clinical use.PurposeIn this work, we aim to determine if smartphones can be used by radiation oncologists or other radiation oncology staff to generate bolus or brachytherapy surface moulds instead of conventional CT with equivalent or comparable accuracy.MethodsThis work involved two separate studies: a phantom and participant study. For the phantom study, a RANDO anthropomorphic phantom (limited to the nose region) was used to generate 3D models based on three different imaging techniques: conventional CT, photogrammetry & LiDAR which were both acquired on a smartphone. Virtual boli were designed in Blender and 3D printed from PLA plastic material. The conformity of each printed boli was assessed by measuring the air gap volume and approximate thickness between the phantom & bolus acquired together on a CT. For the participant study, photographs, and a LiDAR scan of four volunteers were captured using an iPhone 13 Pro™ to assess their feasibility for generating human models. Each virtual 3D model was visually assessed to identify any issues in their reconstruction. The LiDAR models were registered to the photogrammetry models where a distance to agreement analysis was performed to assess their level of similarity. Additionally, a 3D virtual bolus was designed and printed using ABS material from all models to assess their conformity onto the participants skin surface using a verbal feedback method.ResultsThe photogrammetry derived bolus showed comparable conformity to the CT derived bolus while the LiDAR derived bolus showed poorer conformity as shown by their respective air gap volume and thickness measurements. The reconstruction quality of both the photogrammetry and LiDAR models of the volunteers was inadequate in regions of facial hair and occlusion, which may lead to clinically unacceptable patient‐specific device that are created from these areas. All participants found the photogrammetry 3D printed bolus to conform to their nose region with minimal room to move while three of the four participants found the LiDAR was acceptable and could be positioned comfortably over their entire nose.ConclusionsSmartphone‐based photogrammetry and LiDAR software show great potential for future use in generating 3D reference models for radiation oncology purposes. Further investigations into whether they can be used to fabricate clinically acceptable patient‐specific devices on a larger and more diverse cohort of participants and anatomical locations is required for a thorough validation of their clinical usefulness.

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Assessing the fit of 3D printed bolus from CT, optical scanner and photogrammetry methods

Cited by 14 publications

References 15 publications

Evaluation of optical 3D scanning system for radiotherapy use

Evaluation of optical 3D scanning system for radiotherapy use

A dosimetric comparison of CT- and photogrammetry- generated 3D printed HDR brachytherapy surface applicators

An evaluation of consumer smartphones for generating bolus and surface mould applicators for radiation oncology

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