# Low-Cost and Easily Fabricated Ultrasound-Guided Breast Phantom for Breast Biopsy Training
###### Abstract  
We aimed to develop an inexpensive and easy-to-fabricate gelatin-based training phantom for improving the breast biopsy skill and confidence level of residents. [PERSON]'s modulus and acoustic properties of the gelatin tissue phantom and simulated tumors were investigated. Six residents were requested to evaluate the effectiveness of the breast phantom. The results showed that 83% (\(n=5\)) of the participants agreed that the ultrasound image quality produced by the breast phantom was excellent or good. Only 17% (\(n=1\)) of the participants claimed that there was room for improvement for the haptic feedback they received during the placement of the core needle into the breast phantom. The mean pre-instructional score was 17% (SD 17%) for all participants. The mean post-instructional score was 83% (SD 17%), giving an overall improvement of 67%. In conclusion, the mean needle biopsy skill and confidence levels of the participants substantially increased through simulation training on our breast phantom. The participants' feedback showed the phantom is sufficiently realistic in terms of ultrasound imaging and haptic feedback during needle insertion; thus, the training outcome can be linked to the performance of residents when they perform a live biopsy. acoustic properties; breast biopsy; haptic feedback; training phantom; ultrasound imaging 2021 2020 August 2021 22 August 2021 2  
average Young's modulus is 0.69-24 kPa for normal fat tissue, 0.73-271.8 kPa for normal glandular tissue, 3.4-2162 kPa for tumor tissue (ductal carcinoma in situ) and 10-1366.5 kPa for tumor tissue (invasive ductal carcinoma) [9]. This wide variation in [PERSON]'s modulus is found both across and within various tissue types. The variation is particularly large in normal fat and fibroglandular tissues. The acoustic properties of real tissues vary among people and are not constant even within a person's body, giving rise to considerable variation in the literature [10; 11]. Ultrasound-guided breast biopsy is commonly used for tissue diagnoses of sonographically visible breast lesions. Nevertheless, many radiology residents in their graduate residencies have no hands-on experience in performing the procedure [12]. Until now, the traditional apprenticeship training method on live patients has been practiced in the medical field instead of simulation training. The Accreditation Council for Graduate Medical Education has strongly encouraged enhancing safety, predictability and respect for patients by increasing the use of simulation training in graduate medical education [13]. Hence, there is a clinically unmet need for training phantoms. In several residency training programs, turkey breast or gel breast phantoms are commonly used for simulation training of freehand ultrasound-guided breast procedures, as discussed below. Pimento within the olive was embedded within a turkey breast to simulate the target for biopsy training [14]. To develop a breast phantom that has more realistic tactility and appearance in ultrasound images, a chicken breast phantom was embedded with polyvinyl acetate lesions to mimic the heterogeneity of real breast tissue [15]. Gelatin-based phantoms are the most described simulation technique in the literature [12; 16; 17; 18; 19; 20; 21; 22]. In these studies, pitted olives with pimentos, capers, grapes, peas, potatoes and strawberries were used to simulate breast masses for ultrasound-guided core biopsy; rubber glove fingers filled with water and bath oil beads coated with nail polish were used to simulate breast cysts for ultrasound-guided fine-needle aspiration. Plastic beads were embedded in the gelatin-based phantom developed by the [PERSON] group [23]. [PERSON] et al. proposed a gelatin-based breast phantom consisting of a simulated tumor with realistic imaging properties [24]. The background used in breast tissue simulation was made of ballistic gelatin powder and Metamucil, whereas the simulated tumors were composed of barium sulfate, copper sulfate, Metamucil and ballistic gelatin. [PERSON] et al.