Utility of a patient specific MR-based 3D-printed Prostate Model for Dosimetric Validation of Stereotactic Body Radiation to the Prostate with Simultaneous Integrated Dose Escalation to the Dominant Lesion.

Congress:

ECR 2018

Poster Number:

C-2879

Type:

Scientific Exhibit

Keywords:

Multidisciplinary cancer care, Image guided radiotherapy, Cancer, Stereotactic radiotherapy, Computer Applications-3D, MR, Oncology, Genital / Reproductive system male

Authors:

N. Shaafi Kabiri¹, S. Yu¹, A. Hirsch², C. Lee³, C. C. Jaffe², H. Xiang², K. Thomas¹, B. N. Bloch¹; ¹Boston/US, ²Boston, MA/US, ³Needham/US

DOI:

10.1594/ecr2018/C-2879

DOI-Link:

https://dx.doi.org/10.1594/ecr2018/C-2879

Fig. 1: Pelvic Phantom: The phantom is composed of human bone and plastic with same...

Fig. 6: The 3D printed prostate contained within the insert is placed into the pelvic...

Fig. 2: 3D printed prostate model derived from T2-weighted/dynamic contrast enhanced MR...

Fig. 7: Isodose line in axial, coronal and sagittal views and DVH of PTV and index...

$Fig. 8: Measured (thin line) vs. Planed (thick line) isodose line for one fraction of the treatment plan. Gamma passing with 2%2mm, 99.8%.$

Fig. 8: Measured (thin line) vs. Planed (thick line) isodose line for one fraction of...

$Fig. 8: Measured (thin line) vs. Planed (thick line) isodose line for one fraction of the treatment plan. Gamma passing with 2%2mm, 99.8%.$

Fig. 8: Measured (thin line) vs. Planed (thick line) isodose line for one fraction of...

Fig. 3: Red: Index lesion with beginning extra capsular extension toward the...

Fig. 5: Phantom Insert: The 3D prostate model was inserted into this insert

Fig. 4: 3D printed prostate model with EBT3 films in the location of significant...

Aims and objectives

Recent advances in radiation therapy for the treatment of prostate cancer has allowed for focal radiation therapy and reduction of normal tissue volume included in the planning [1, 2]. Moreover, the use of three-dimensional (3D) printing has become an area of interest in the radiation therapy and medical physics community as a tool for quality assurance and/or patient treatment [3, 4]. The use of a novel MR-based 3D-printed prostate model insert in planning and delivering robotic prostate Stereotactic Body Radiation Therapy (SBRT) with simultaneous integrated...

Methods and materials

A patient specific 3D-printed prostate model, which included the prostate, DIL, seminal vesicles, urethra, neurovascular bundles, penile bulb, and rectum was generated from a combined T2-weighted/dynamic contrast enhanced MR Image. The 3D-printed prostate model was placed in a water-filled insert and positioned in a cavity of an anthropomorphic pelvis phantom for CT-based planning (Figure 5 and 6). A SBRT plan of non-coplanar and non-isocentric beams was generated using sequential optimization to have 36.25 Gy total (5 fractions of 7.25 Gy) cover the Planning Target Volume...

Results

Concordant with the RTOG0938 guidelines, 36.25 Gy covered 95% of the PTV volume, and DIL had mean dose of 40.50 Gy, and required OAR constraints were met. Comparison of the delivered and planned dose distribution yielded 99.8% passing rates under Gamma criteria of 2%/2mm (Figure 8).

Conclusion

By including all relevant clinical and radiosensitive intra- and periprostatic structures, the novel patient specific MRI-based 3D prostate/pelvic phantom offers a personalized,more accurate, structure and target specific treatment planning, superior to any other method that are currently available.

Personal information

References

1. Dulaney, C. R., Osula, D. O., Yang, E. S., & Rais-Bahrami, S. (2016). Prostate Radiotherapy in the Era of Advanced Imaging and Precision Medicine. Prostate Cancer, 2016, 1–10. https://doi.org/10.1155/2016/4897515 2. Katz, A. J. (2010). CyberKnife Radiosurgery for Prostate Cancer. Technology in Cancer Research & Treatment, 9(5), 463–472. https://doi.org/10.1177/153303461000900504 3.Madamesila, J., McGeachy, P., Villarreal Barajas, J. E., & Khan, R. (2016). Characterizing 3D printing in the fabrication of variable density phantoms for quality assurance of radiotherapy. Physica Medica, 32(1), 242–247. https://doi.org/10.1016/j.ejmp.2015.09.013 4.Ehler, E. D., Barney,...