Technical Note: an algorithm and software for conversion of radiotherapy contour‐sequence data to ready‐to‐print 3D structures

Use of 3D Printing Technology to Improve Lead Shield Fabrication for Electron Therapy of the Face

Superficial lesions of the face are often treated with an electron beam and surface collimation utilizing a conformal lead shield with an opening around the region of treatment (ROT). To fabricate the lead shield, an imprint of the patient face is needed. Historically, this was achieved using a laborious and time-consuming process that involved a gypsum imprinted model (GIM) of the patient topography. We propose utilization of 3-dimentional (3D) printing technology to create a 3-dimensional printed custom model (3D-PCM) of the patient facial topography as a more accurate and more efficient alternative to GIM. GIM and 3D-PCM were generated for three patients requiring en face electron therapy of the nose. The models for both methods were then CT-scanned and fused rigidly to the CT of the patient. The accuracy of the models was compared with the CT image of the patient via visual inspection and the Sørensen-Dice similarity coefficient (DSC). The efficiency of the two methods was evaluated by the average time needed to complete each process based on user-reported experience. The average DSC between the patient and GIM is 0.95336 (standard deviation (SD) = 0.0099479), while the average DSC of the patient and 3D-PCM is 0.97886 (SD = 0.0037441). With respect to efficiency, the average time to fabricate and dry GIM is 54.5 hours with hands-on time of 2.5 hours, while generation of 3D-PCM takes about 6.5 hours, with hands on time of approximately 2.5 hours. 3D-PCMs based on CT scan images are found to be an excellent substitute for GIMs by exhibiting a higher degree of fidelity with patient's anatomy, requiring significantly less time to complete, being less labor intensive, and allowing for greater patient comfort. The disadvantage of exposing the patient to radiation associated with the CT scan image acquisition for designing a 3D-PCM could be eliminated by employing 3D-camera scanning technology.

The design and characterization of a novel dynamic collimator system for synchrotron radiotherapy applications

BACKGROUND

Novel synchrotron radiotherapy techniques are currently limited to using prefabricated beam-limiting blocks for field definition. For large experiments, a single square tungsten block is often used for every treatment since conformal blocks are both patient and field specific, and require long lead times for fabrication. Future synchrotron radiotherapy treatments would benefit from a dynamic collimator system.

PURPOSE

We developed and tested a novel collimator design for use on the Imaging and Medical Beamline (IMBL) at the ANSTO Australian Synchrotron.

METHODS

The maximum usable beam size on IMBL is 50-mm wide by 3-mm tall. Given the beam shape, targets must be vertically scanned through the synchrotron beam to cover the target volume. To shape the beam, a novel collimator design was developed, consisting of two semi-circular leaves made from 4-mm thick tungsten sheets, with each leaf capable of both vertical and horizontal movement. A software model was created to optimize motor trajectories and generate deliverable treatment fields. A series of geometric field shapes and clinical target volumes were delivered using the collimator and imaged with a digital imaging detector. Four similarity metrics (volumetric similarity, DICE, and the average and maximum Hausdorff distances) were used to measure differences between the input and planned fields, and the planned and delivered fields.

RESULTS

Differences between input and planned fields increased with delivery speed, and were worse for rectangular and square fields compared to circular fields. However, the differences between planned and delivered fields were small, where the maximum average deviation between the fields was 0.25 mm (one pixel). Field repeatability was consistent with no difference (σ = 0 for all metrics) observed in consecutively delivered fields.

CONCLUSIONS

We have successfully built and demonstrated a novel collimator for synchrotron radiotherapy applications on IMBL. Several design improvements have been highlighted and will be addressed in future revisions the collimator. However, in its current state, the collimator enables dynamically delivered conformal treatment fields to be utilized on IMBL, and is ready to support the forthcoming canine treatments on IMBL.

The Role of 3D Printing in Planning Complex Medical Procedures and Training of Medical Professionals-Cross-Sectional Multispecialty Review

Medicine is a rapidly-evolving discipline, with progress picking up pace with each passing decade. This constant evolution results in the introduction of new tools and methods, which in turn occasionally leads to paradigm shifts across the affected medical fields. The following review attempts to showcase how 3D printing has begun to reshape and improve processes across various medical specialties and where it has the potential to make a significant impact. The current state-of-the-art, as well as real-life clinical applications of 3D printing, are reflected in the perspectives of specialists practicing in the selected disciplines, with a focus on pre-procedural planning, simulation (rehearsal) of non-routine procedures, and on medical education and training. A review of the latest multidisciplinary literature on the subject offers a general summary of the advances enabled by 3D printing. Numerous advantages and applications were found, such as gaining better insight into patient-specific anatomy, better pre-operative planning, mock simulated surgeries, simulation-based training and education, development of surgical guides and other tools, patient-specific implants, bioprinted organs or structures, and counseling of patients. It was evident that pre-procedural planning and rehearsing of unusual or difficult procedures and training of medical professionals in these procedures are extremely useful and transformative.

Additive 3-dimensional printing as a novel tool for pre- and postsurgical evaluation and patient education: A clinical case series

BACKGROUND AND OVERVIEW

In contrast to subtractive 3-dimensional (3D) techniques synonymous with computer-aided design and computer-aided manufacturing, rapid progress in additive 3D printing, especially fused filament fabrication or fused deposition modeling, can change the practice of dentistry.

CASE DESCRIPTION

In this article, the authors outline the digital workflow for fused filament fabrication and fused deposition modeling 3D printing that involves converting a Digital Imaging and Communications in Medicine file (scan or radiograph) to a printable Standard Triangle Language file that can be modified (additions or manipulations) using a readily accessible software for 3D printing. The authors also present a clinical case series showing various applications for this technique, including clinician and patient education, treatment planning, and posttreatment evaluations.

CONCLUSIONS AND PRACTICAL IMPLICATIONS

The low cost and simple workflow of additive 3D printing has potential to improve precision and efficiency in clinical dentistry for both academic and private practices.