One Minute Poster Pitches Archive

UK & Ireland Prostate Brachytherapy Conference 2024

Abstract number 12 

Development of a Prostate Tissue Mimicking Material and Reusable Phantom for MRI Biopsy and Brachytherapy 

Sarah Wilby, Antony Palmer, Wojciech Polak
Portsmouth Hospitals University NHS trust 

Andrea Bucchi, Petko Petkov
University of Portsmouth 

Purpose: Develop and test, a novel reusable phantom for simulation of MRI-guided prostate biopsy and brachytherapy. 

1) Evaluate MRI and mechanical properties of a novel prostate tissue mimicking material (PTMM). 

2) Construct a reusable prostate phantom (PROM) for brachytherapy or biopsy. 

Method: MRI evaluation of PTMMs to determine relaxation times for gels containing 0 to 0.6 ml of Gadovist and 0 to 6 g of Konjac powder (per 100 ml final product). 

Mechanical measurement of force needed for needle insertion into PTMMs, whilst moving at a constant 8mm/s, for PTMMs containing 2 to 12 g Konjac. Calculation of Youngs Modulus (EM) at 10% strain. 

Needle-tissue interaction plots, of Force vs Distance through the PROM phantom, were generated. 

Results: Imaging: T1 increased (250 to 1725 mS) and T2 reduced (300 to 30 mS) as Gadovist was increased from 0 to 0.6 ml/100 ml, incorporating typical T1 / T2 times for prostate [1]. With ≥ 0.2 ml of Gadovist present, the quantity of Konjac has no effect on relaxation times. 

A key feature of the PROM phantom is the refillable soft silicon prostate shell abutting a full or empty bladder, to simulate a fixed or mobile prostate respectively. 

Live MRI biopsy showed ≤ 1.5 cm and ≤ 0.36 cm of prostate displacement in the superior and anterior directions respectively, in line with clinical data [2]. 

Mechanical: At 30 mm insertion distance, force on the needle was 0.05 N and 1.5 N, with 2 and 12 g of Konjac respectively. EM increased from 5 to 53 kPa (2 and 12 g Konjac respectively). Plots of force versus distance through the PROM phantom showed detectable anatomical boundaries. 

Conclusions: Gadovist and Konjac within the PTMM allow augmentation of mechanical properties whilst maintaining MR characteristics. The PTMM can be used within the PROM phantom for repeated biopsy / brachytherapy training. 

References: 

1. De Bazelaire CMJ, Duhamel GD, Rofsky NM, et al. MR Imaging Relaxation Times of Abdominal and Pelvic Tissues Measured in Vivo at 3.0 T: Preliminary Results. Radiology 2004; 230: 652–659. 
2. Stone NN, Roy J, Hong S, et al. Prostate gland motion and deformation caused by needle placement during brachytherapy. Brachytherapy 2002; 1: 154–160.