Jump to content

Dr Tatiana

Member With Blog
  • Content Count

  • Joined

  • Last visited

  • Days Won


Dr Tatiana last won the day on June 21 2016

Dr Tatiana had the most liked content!

1 Follower

About Dr Tatiana

  • Rank
    Advanced Member & Blogger

Recent Profile Visitors

1,404 profile views
  1. The Coalition for Imaging and Bioengineering Research (CIBR) is a dedicated partnership of academic radiology departments, patient advocacy groups, and industry with the mission of enhancing patient care through advances in Biomedical Imaging. My good friend and colleague Dr. Beth Ripley and I recently participated in the sixth annual Medical Technology Showcase at Capitol Hill organized by CIBR, representing the Department of Radiology at the Brigham and Women’s Hospital (BWH) where we emphasized the importance of 3D printing in healthcare. The annual Medical Technology showcase aims to bring examples of medical breakthroughs in imaging and bioengineering to members of congress and demonstrate how these advances are impacting patient care. In addition to educating policy makers and the public about innovative imaging technology, the event demonstrates the value of NIH funded academic research and the importance of collaborations between academia, industry and patient advocacy groups. Our display booth comprised of the Department of Radiology at BWH, the Lung Cancer Alliance, and Fujifilm was a hit among attendees and we were pleased to see the level of interest in medical 3D printing. We displayed 3D printed models that have been used for different clinical applications and our booth partners from Fujifilm demonstrated Synapse 3D, a software that allows conversion of 2D image data from CT/MRI into 3D printable files. Our goal was to demonstrate the importance of 3D printing in pre-surgical planning and how it can benefit patients by allowing surgeons to devise a patient specific treatment strategy and minimize post-surgical complications. Sheila Ross, a lung cancer survivor and patient advocate from the Lung Cancer Alliance emphasized how 3D printed models can give patients and their families a better understanding of the planned procedure. A lung model from Fujifilm demonstrating a nodule (green) and surrounding bronchioles The Lung & Brain cookies might have been slightly more popular than our 3D models It is our hope that more funding and resources will be allocated to investigate innovative medical technologies such as 3D printing, which can then be translated to impact patient care. In order to transform 3D printing from being a fad, to a mainstream tool that fosters precision medicine, evidence based benefits of its different applications will need to be demonstrated in clinical trials which will require funding. Tatiana Kelil, MD
  2. An entirely new 3D printing method that prints 25-100x faster than currently available technologies has been introduced. The new process called Continuous Liquid Interface Production Technology (CLIP) works by using light and oxygen to change a photosensitive liquid resin into a three dimensional solid object. The process is similar to Stereolithography (SLA) where liquid photopolymers are cured using ultraviolet light. However instead of depositing material layer by layer, the object is formed at once. CLIP places a pool of liquid resin over a digital projection system which projects an image for how each layer should form. To create an object, bursts of light and oxygen are applied; light hardens the resin while areas exposed to oxygen are kept from hardening. Proposed advantages of this technology include radically faster processing time and ability to use wide range of materials that make stronger objects. This technology can potentially be extremely useful in the health care industry if models can be printed within a matter of minutes and enable preoperative planning of surgical procedures that may be time sensitive. For a summary of other 3D printing technologies, check out my previous post here Tatiana Kelil, MD
  3. If you are like me and have no real background in engineering or chemistry, keeping the different 3D printing technologies straight may sound daunting. In this post, I will attempt to give a simplified overview of the seven major types of 3D printing technologies and summarize the key advantages and disadvantages for each. I hope this information helps anyone who is interested in acquiring a 3D printer understand the different processes better and direct you to a specific technology that suits your needs the best. 3D printing is an additive process that creates volume by adding material one layer at a time following a predetermined pattern as opposed to milling, where material is removed from a raw block. The American Society for Testing Materials (ATSM) has defined seven major additive manufacturing processes, each represented by one or more commercial technologies. 1) Vat photopolymerization (Stereolithography, SLA) Invented over 30 years ago, SLA is the foundational technology of 3D printing. In this process an ultraviolet light is applied to a vat (large tub) containing liquid photopolymer (plastic). UV light is used to cure the liquid photopolymer (convert the liquid into a solid state). When a layer is completed, a leveling blade is moved across the surface to smooth it before depositing the next layer. This process is repeated until the model is completed. Support structures are needed which anchor the parts on the build platform and support overhanging structures. Once complete, the part is drained and excess polymer is rinsed off. A final cure in a UV oven is often required to further solidify the object. Advantage: - High resolution and accuracy - Allows production of complex geometries Disadvantages: - Durability; photopolymers are the weakest material 2) Material extrusion (Fused Deposition Modeling, FDM) This process is analogous to a hot glue gun where a printer melts a cable roll of raw material (usually plastic) and extrudes it through a nozzle. Through the use of a second nozzle, a support structure can be built using a different material. The melted material is laid down on the build platform layer by layer, where it cools and solidifies. Once complete, support material is either mechanically removed or melted away. The majority of commercially available desktop printers are currently of the FDM type. Advantages: - Multiple materials/colors may be used for both build and support - Affordable, easy to use, can fit in an office Disadvantages: - Relatively slow build times - Limited surface quality, fine details may not be realized - Care needs to be taken during design to optimize final object strength 3) Material Jetting (Multijet modeling) This process is analogous to inkjet printing, but instead of jetting drops of ink onto paper, a 3D printer jets drops of liquid photopolymer onto the build tray. Liquid drops are then converted into a solid state using light. Support materials are required which are either mechanically removed or melted away once building is complete. Material jetting can combine different materials within the same 3D printed model, in the same print job. Fully cured models can be handled and used immediately without additional post-curing processes. Advantage: - High accuracy and surface finishes - Can combine different materials within the same 3D printed model Disadvantages: - Durability, Photopolymers are the weakest material 4a) Powder bed fusion (Selective Laser Sintering, SLS) This process uses laser to selectively sinter (melt and fuse) a thin layer of powdered material. The build platform will then be lowered and the next layer of plastic powder will be laid out on top. By repeating the process of laying out powder and melting where needed, the parts are built up in the powder bed. Unsintered loose powder supports the object during build so no other support structures are needed. The loose powder must be removed from the completed object. Advantages: - Relatively rapid build time - No support material is needed - Can manufacture parts in standard plastics - Low cost Disadvantages: - Surface finish can be rough 4b) Powder bed fusion (Electron Beam Melting, EBM) This process is similar to SLS, but uses electron beam instead of laser to melt and fuse a thin layer of powdered metal into a solid object. Completed object is embedded in a block of loose powder, which must be removed. Advantages: - Relatively rapid build time - Material recyclability is often possible, reducing potential waste. - Useful in settings that require complex internal structures for metal components Disadvantages: - Relatively high cost for the systems and the knowledgeable operators required to run them - Surface finish can be rough 5) Binder jetting (Powder bed and inkjet head printing) In this process a print head moves across a powder bed, laying down a liquid binding agent that glues the particles together to create a solid object. The built parts lie in the bed of loose powder, so no support structure is needed. Advantages:- Relatively rapid build time - No support material is needed - Simple and inexpensive technology - Can print a wide range of materials in full color Disadvantages: - Objects are relatively fragile and require post processing to improve durability 6) Sheet lamination This process stacks sheets of materials using binding agents (adhesives) or other joining processes such as friction welding and then cuts the edges of each layer to create the desired shape. Advantage: - Does not require a controlled environment and can be run in open air - Can be used to join dissimilar materials Disadvantages: - Ability to produce complex objects is limited 7) Directed energy deposition (Laser metal deposition) In this process material is directly deposited by jetting the build material into the heated zone created by a laser, electron beam or an ionized gas. Advantage: - Can operate in open air and at large scale - Multiple materials can be used in the same process - Good at processing a high volume of material quickly and inexpensively Disadvantages: - Lower accuracy and reduced ability to create complex objects Now that you have some idea about the different 3D printing technologies, I hope you will get a 3D printer of your choice and print your heart out! Tatiana Kelil, MD Sources: custompart.net, mechanicalengineeringblog.com, additively.com, 3dsystems.com, Deloitte University Press
  4. Thanks Mike! That is really interesting. It seems like we have only seen the tip of the iceberg when it comes to applications of 3D printing in medicine and many more applications are going to be evident as this technology continues to be explored.
  5. Enduring the physical and psychological consequences of having a cancer diagnosis is only the beginning of the battle. Cancer patients then have to deal with grueling treatment cycles and associated side effects. The high doses of radiation used to destroy cancer cells can also damage adjacent healthy tissues. Although major improvements in radiation technology such as intensity modulated radiation therapy have led to reduced toxicity, these methods tend to be complex requiring several planning steps and safety checks before the patient can start treatment. 3D printing is promising to solve some of these problems and aid in providing personalized cancer treatment. One such application of 3D printing is in the production of customized bolus and shields used during radiotherapy. A bolus is an artificial object placed over the treatment area in order to modify dose both at the skin surface and at depth while a shield is used to protect adjacent structures not intended to be exposed to radiation. 3D printing can be used to design customized bolus and shield that fit a patient’s unique anatomy perfectly. Additionally these precise models ensure even distribution of radiation dose to the targeted area while sparing adjacent normal tissues. This technology is especially beneficial to patients with head and neck cancers where susceptible organs such as the eyes and ears are located in close proximity to the target and where surface anatomy of the face is varied among different individuals. Traditional approaches of fabricating shields involve casting of several molds, which are expensive, time consuming and labor intensive. 3D printed shields can be easily and cost effectively created from existing CT/MR images without subjecting sick patients to be present during the fabrication process. Another application of 3D printing is in Brachytherapy where a radiation source is implanted inside the body next to the area requiring treatment. Under current practice, a one-size-fits-all approach is utilized where standardized implants with internal channels that guide the radiation source are inserted into the body. Standardized implants do not conform to patients’ specific anatomy and precise positioning is often challenging. These implants are also prone to shift during movement resulting in suboptimal dose to the target and unwanted exposure to adjacent organs. Patients are therefore required to remain immobile over the course of a treatment to maintain optimal positioning between the radiation source and treatment target. 3D printed customized implants provide a much better fit and are easier to place thereby increasing patient comfort and reducing shifts due to movement or changes in bladder or bowel distention. Customized implants with curved internal channels can also be used to reach targets that may not be accessible with existing standardized implants. 3D printing appears to provide a rapid, practical and inexpensive approach to deliver homogeneous dose to the target area while minimizing unwanted exposure to adjacent normal tissues. Furthermore this technology minimizes patient discomfort and allows provision of cancer therapy that is tailored to each individual. Tatiana Kelil, MD Sources: Garg et al. IEEE.org 2013 Su et al. JACMP.org 2014
  6. Thanks Dr Baumel, I will have a post on applications of 3D printing in radiation oncology soon.
  7. Within the past few years, interest in 3D printing and its medical applications has been growing exponentially. 3D printed models have already been used to provide unparalleled pre-surgical planning in complex surgeries such as conjoined twin separation and face transplantation, as well as more common procedures such as fracture fixations and joint replacements. However, the majority of health care providers and recipients are still unaware of this technology and its utility. My hope with this blog is to provide a basic overview of 3D printing and its applications in medicine by answering some of the frequently raised questions. Stay tuned for future blogs where I will attempt to address specific topics in detail! What is 3D printing? 3D printing is a process of creating 3 dimensional objects from a digital file by using a 3D printer. In the field of medicine, the digital files are comprised of 2 dimensional CT or MR images. 3D printers do not directly recognize these digital files and post processing steps are required to convert these files into a format that is readable by 3D printers. The printer then deposits various materials layer by layer to build a 3 dimensional object. What are the applications of 3D printing in medicine? 3D models have already been used for presurgical planning in numerous subspecialties including maxillofacial and craniofacial surgery, orthopedic surgery, neurosurgery, cardiovascular surgery, pediatrics and dentistry. Models can also been used to design implants and prosthesis that are customized to each patient. In the field of radiation oncology, 3D models can be used for radiotherapy planning of optimal positioning of radiation beam and creation of personally designed radiation shields. 3D models are also proving to be superb educational tools for teaching anatomy, pathology and surgical techniques. Bioprinting, which involves printing of live cells and viable tissues that can potentially be implanted into human beings is currently an active filed of research. What are the benefits of 3D printed models that have already been reported? Currently, 3D printed models are predominantly utilized by surgeons. Preoperatively these models improve diagnosis and evaluation of the complexity of the procedure thereby allowing selection of optimal, patient-specific treatment strategy. The models can be used to plan every step of a complex procedure including surgical point of entry, incision size, precise screw length and trajectory. The models can also serve as a cutting guide for resection and as a template for preoperative bending of reconstruction hardware that would fit the specific patient anatomy perfectly. As a result of this accurate preoperative simulation and preparation, 3D models result in reduced actual operating time and cost associated with the use of surgical rooms. The time that the patient has to remain under general anesthesia, amount of blood loss and other potential complications are subsequently minimized. Shortened hospital stay and decreased need for follow up procedures have also been reported. 3D printed models allow patients who typically don’t have years of medical training, to visualize and better understand the planned procedure and make it easier for surgeons to obtain informed consents from their patients. What is the purpose of printing models if 3D images can be viewed on a computer screen? Although a 3 dimensional volume rendered digital models can be created, these digital models are still viewed on a 2 dimensional computer screen, which does not provide the same sensory input as holding a physical model in hand. Surgeons that have used the models report the additional tactile sensory input gained by holding the models and the ability to rotate and view the models from any direction in space greatly enhances their spatial perception of anatomic relationships between adjacent structures. Additionally the models provide the added benefits mentioned above such as serving as a cutting guide and template for pre-surgical bending of reconstruction plates, which cannot be achieved unless these models are printed into tangible objects. In summary, it is hard to imagine all the ways this technology will impact patient care, but judging from what has already been achieved within a very short period of time, 3D printing will certainly revolutionize the healthcare industry for the better. Leave a comment or question below regarding topics you would like addressed on the next blog! Tatiana Kelil, MD Image credit: Healio.com/orthopedics; John Robert Honiball (University of Stellenbosch).
  • Create New...