The Use of Three-Dimensional Printing in Immobilization of Patient's Hand During Radiation Treatment of Grade II Squamous Cell Carcinoma of Proximal Phalanx Co-Morbid with Late Stage Dementia

Abstract

77-year old female patient opted for radiation therapy to treat a grade II squamous cell carcinoma developing on the proximal-medial aspect of the third digit of left hand. The patient was also co-morbid with late stage dementia, thus, presenting problems for patient understanding of the importance of immobilization. Therefore, patient compliance to remain immobilized when radiation therapists left the treatment room was diminished. Since the radiation target was very small (2 cm diameter), effective immobilization was necessary to decrease collateral damage to nearby tissue, and ensure proper treatment of cancerous lesion. Following an initial patient pre-treatment simulation that proved to be non-reproducible, the patient was re-booked for a second simulation. Prior to the appointment CT DICOM data were converted to stereolithography (.stl) file for 3D computer assisted design, and eventual three-dimensional (3D) printing on Ultimaker 2+ device. 3D printing was utilized to create a 3D positive of the patient's digits for creation of a custom wax bolus, as well as a personalized outline of the patient's hand that would be used in conjunction with a thermoplastic mask to ensure immobilization and radiation treatment setup accuracy. The patient received 40.5 GY in 9 fractions using 6 MV photons delivered over a two-week period. Setup and positioning of the treatment area was verified with kV imaging prior to radiation delivery. The 3D printed outline proved to be an effective, accurate, and low-cost way of immobilizing patient's hand in conjunction with traditional methods. This therefore allowed for adequate treatment to be delivered to the area of interest. Upon follow-up, patient presented with a complete clinical response to therapy. This is an interesting and novel case for the possibilities and usage of 3D printing in the immobilization of patients during radiation therapy, especially when presenting with decreased compliance to treatment instructions. In this case, the use of 3D printing therefore ensured a low-cost solution and effective therapy method for the best possible patient outcome.