Cost‐effective immobilization for whole brain radiation therapy

Abstract

To investigate the inter‐ and intra‐fraction motion associated with the use of a low‐cost tape immobilization technique as an alternative to thermoplastic immobilization masks for whole‐brain treatments. The results of this study may be of interest to clinical staff with severely limited resources (e.g., in low‐income countries) and also when treating patients who cannot tolerate standard immobilization masks. Setup reproducibility of eight healthy volunteers was assessed for two different immobilization techniques. (a) One strip of tape was placed across the volunteer's forehead and attached to the sides of the treatment table. (b) A second strip was added to the first, under the chin, and secured to the table above the volunteer's head. After initial positioning, anterior and lateral photographs were acquired. Volunteers were positioned five times with each technique to allow calculation of inter‐fraction reproducibility measurements. To estimate intra‐fraction reproducibility, 5‐minute anterior and lateral videos were taken for each technique per volunteer. An in‐house software was used to analyze the photos and videos to assess setup reproducibility. The maximum intra‐fraction displacement for all volunteers was 2.8 mm. Intra‐fraction motion increased with time on table. The maximum inter‐fraction range of positions for all volunteers was 5.4 mm. The magnitude of inter‐fraction and intra‐fraction motion found using the “1‐strip” and “2‐strip” tape immobilization techniques was comparable to motion restrictions provided by a thermoplastic mask for whole‐brain radiotherapy. The results suggest that tape‐based immobilization techniques represent an economical and useful alternative to the thermoplastic mask.

Radiotherapy Immobilization Mask Molding Through the Use of 3D-Printed Head Models

“…Also, thermoplastic masks may not be suitable for claustrophobic patients, for which other immobilization strategies may be needed. 4 Finally, the current technique requires 36 hours to print the 3D-Head and 3D-NR for each patient. Therefore, this methodology would not be suitable for patients requiring WBRT within 1 to 2 days.…”

“…Alternate techniques to immobilize patients for WBRT, such as ones based on the use of strip tapes instead of thermoplastic masks, had previously been evaluated for claustrophobic patients. 4 …”

“…Alternate techniques to immobilize patients for WBRT, such as ones based on the use of strip tapes instead of thermoplastic masks, had previously been evaluated for claustrophobic patients. 4 Novel applications of additive manufacturing (threedimensional [3D]-printing) technology in radiotherapy have primarily been used to print brachytherapy applicators and bolus materials to improve radiation dose delivery. 5 A prior study has shown the feasibility of 3D-printing heads (3D-Head) and masks using CT-sim images.…”

Whole-brain radiation therapy without a thermoplastic mask

“…Li et al concluded that the comfort and tolerability was improved by using an open-face mask [3]. Even though an open-face mask causes less discomfort compared to a full-head mask, no mask at all would be even better [4,5].…”

3D‐printed headrest for frameless Gamma Knife radiosurgery: Design and validation

“…The headrest was placed in the adapter, and the volunteer laid down. The volunteer's face was immobilized using two pieces of tape based on a low-cost immobilization technique published by Rubinstein et al14 This technique was chosen because it is a simple and robust immobilization technique that has been demonstrated to be able to provide sufficient immobilization for whole-brain radiotherapy, and it was easier to reproduce and verify compared to making a new thermoplastic mask for each of the volunteer trials. Once immobilized in the headrest, a reference scan of the volunteer was acquired in AlignRT Version 5.1 and a region of interest F I G .…”