Technical report: a training phantom for stereotactic breast biopsies

Technical Report: A Cost-Effective, Easily Available Tofu Model for Training Residents in Ultrasound-Guided Fine Needle Thyroid Nodule Targeting Punctures

Objective

To establish a cost-effective and easily available phantom for training residents in ultrasound-guided fine needle thyroid nodule targeting punctures.

Materials and Methods

Tofu, drinking straws filled with coupling gel, a urine tube, and 21-gauge needles were used to generate a phantom thyroid with nodules for training. Twelve radiology residents were involved in the study. The puncture success rates were recorded and compared before and after phantom training using the Wilcoxon signed-rank test.

Results

On ultrasonography, tofu mimicked the texture of the thyroid. Drinking straws filled with coupling gel mimicked vessels. The urine tube filled with air mimicked the trachea, and 21-gauge needles mimicked small nodules in the transverse section. The entire phantom was similar to the structure of the thyroid and surrounding tissues. The puncture success rates of radiology residents were significantly increased from 34.4 ± 14.2% to 66.7 ± 19.5% after training (p = 0.003). The phantom was constructed in approximately 10 minutes and materials cost less than CNY 10 (approximately $ 1.5) at a local store.

Conclusion

The tofu model was cost-effective, easily attainable, and effective for training residents in ultrasound-guided fine needle thyroid nodule targeting punctures in vitro.

Ultrasound-guided breast biopsy for surgical residents: evaluation of a phantom model

BACKGROUND

Ultrasound is increasingly used by surgeons for evaluation of breast lesions. While surgical residents have sufficient exposure to breast surgery, many lack exposure to office-based procedures, such as ultrasound-guided breast biopsy. A phantom model was created to teach surgical residents basic breast ultrasound and biopsy skills and to evaluate the resident's response when incorporated into the curriculum.

METHODS

The model was created using a pork roast and 10 variably-sized pimento olives. Twenty-four surgical residents were given a brief introduction to breast ultrasound followed by up to 5 minutes to ultrasound the model and note the embedded lesions. The number and location of lesions found and the time spent per resident were recorded. Residents were then introduced to the vacuum-assisted core biopsy system and observed performing ultrasound-guided biopsies. Pre- and postsession evaluations were completed by all residents. Scatterplot regression models were used for data analysis.

RESULTS

Most residents had previous ultrasound instruction. The intermediate level residents (postgraduate year [PGY]2 and 3) found the most lesions in the shortest time, missing on average 1.125 lesions in 3:09 minutes. Time spent did not correlate with number missed or previous ultrasound experience. Over 50% of residents sampled the center of the lesion on their first biopsy attempt, with no correlation to PGY or ultrasound experience. All residents rated this experience good to excellent, and 67% believed their ultrasound skills were improved. Ninety-five percent of residents felt the model was fairly realistic and 95% would like to have more experiences like this in the curriculum. The residents surveyed thought the curriculum would be best suited to a PGY2 experience.

CONCLUSIONS

The phantom breast is a realistic and valuable teaching model for breast ultrasound. Further evaluation regarding skill retention is needed.

CT-guided procedures: evaluation of a phantom system to teach accurate needle placement

AIM

To evaluate the use of a phantom system to help teach the basic techniques of accurate CT-guided needle placement, thereby avoiding the risks associated with teaching on patients.

MATERIALS AND METHODS

Gelatine phantoms with five, 1.9 cm embedded spherical wooden targets were constructed. Four trainee operators performed 15 simulated biopsy procedures on the targets (series one) and repeated identical procedures 2 weeks later (series two). Statistical analysis of accuracy of needle placement and subject confidence were performed.

RESULTS

Significant sequential improvement in axial plane angular error was noted with the average error decreasing by 0.33 degrees after every five procedures performed (95% CI: -0.58 to -0.08, p=0.01). Operator confidence indicated significant improvement both within each series and from series one to series two (95% CI: 0.08 to 1.17, p=0.025 and 95% CI: 0.00 to 0.58, p=0.05) respectively. However, variability in operator performance made statistically significant improvement in other variables unproven.

CONCLUSION

Despite the study comprising a relatively small number of participants and procedures, it clearly demonstrated the effectiveness of teaching operators to perform CT-guided procedures using a phantom system. Needle placement accuracy significantly improved, with a reduction in axial angular error, and improved operator confidence without the risks associated with training on patients. Three of the operators in this study had never performed a CT-guided procedure previously, and their proficiency, after a relatively short but intense period of training, was impressive. The use of phantoms should be considered routinely for basic training of CT-guided needle placement.

Low-Cost Phantom for Stereotactic Breast Biopsy Training

OBJECTIVE

This article reports on the construction of a low-cost phantom to be used for training technologists, residents, and radiologists to perform stereotactic breast biopsy. The model is adaptable to a variety of biopsy devices and realistically simulates the aspects of stereotactic breast biopsy.

CONCLUSION

We believe our model provides an excellent alternative to more expensive commercial products.