Browsing by Author "Salama, Joseph K"

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    Fostering Radiation Oncology Physician Scientist Trainees Within a Diverse Workforce: The Radiation Oncology Research Scholar Track.
    (International journal of radiation oncology, biology, physics, 2021-06) Salama, Joseph K; Floyd, Scott R; Willett, Christopher G; Kirsch, David G
    There is a need to foster future generations of radiation oncology physician scientists, but the number of radiation oncologists with sufficient education, training, and funding to make transformative discoveries is relatively small. A large number of MD/PhD graduates have entered he field of radiation oncology over the past 2 decades, but this has not led to a significant cohort of externally funded physician scientists. Because radiation oncologists leading independent research labs have the potential to make transformative discoveries that advance our field and positively affect patients with cancer, we created the Duke Radiation Oncology Research Scholar (RORS) Program. In crafting this program, we sought to eliminate barriers preventing radiation oncology trainees from becoming independent physician scientists. The RORS program integrates the existing American Board of Radiology Holman Pathway with a 2-year post-graduate medical education instructor position with 80% research effort at the same institution. We use a separate match for RORS and traditional residency pathways, which we hope will increase the diversity of our residency program. Since the inception of the RORS program, we have matched 2 trainees into our program. We encourage other radiation oncology residency programs at peer institutions to consider this training pathway as a means to foster the development of independent physician scientists and a diverse workforce in radiation oncology.
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    Hypofractionated Image-Guided Radiation Therapy With Simultaneous-Integrated Boost Technique for Limited Metastases: A Multi-Institutional Analysis.
    (Frontiers in Oncology, 2019-01) Jacobs, Corbin D; Palta, Manisha; Williamson, Hannah; Price, Jeremy G; Czito, Brian G; Salama, Joseph K; Moravan, Michael J
    Purpose: To perform a multi-institutional analysis following treatment of limited osseous and/or nodal metastases in patients using a novel hypofractionated image-guided radiotherapy with simultaneous-integrated boost (HIGRT-SIB) technique. Methods: Consecutive patients treated with HIGRT-SIB for ≤5 active metastases at Duke University Medical Center or Durham Veterans' Affairs Medical Center between 2013 and 2018 were analyzed to determine toxicities and recurrence patterns following treatment. Most patients received 50 Gy to the PTVboost and 30 Gy to the PTVelect simultaneously in 10 fractions. High-dose treatment volume recurrence (HDTVR) and low-dose treatment volume recurrence (LDTVR) were defined as recurrences within PTVboost and PTVelect, respectively. Marginal recurrence (MR) was defined as recurrence outside PTVelect, but within the adjacent bone or nodal chain. Distant recurrence (DR) was defined as recurrences not meeting HDTVR, LDTVR, or MR criteria. Freedom from pain recurrence (FFPR) was calculated in patients with painful osseous metastases prior to HIGRT-SIB. Outcome rates were estimated at 12 months using the Kaplan-Meier method. Results: Forty-two patients met inclusion criteria with 59 sites treated with HIGRT-SIB (53% nodal and 47% osseous). Median time from diagnosis to first metastasis was 31 months and the median age at HIGRT-SIB was 69 years. The most common primary tumors were prostate (36%), gastrointestinal (24%), and lung (24%). Median follow-up was 11 months. One acute grade ≥3 toxicity (febrile neutropenia) occurred after docetaxel administration immediately following HIGRT-SIB. Four patients developed late grade ≥3 toxicities: two ipsilateral vocal cord paralyzes and two vertebral compression fractures. The overall pain response rate was 94% and the estimated FFPR at 12 months was 72%. The estimated 12 month rate of HDTVR, LDTVR, MR, and DR was 3.6, 6.2, 7.6, and 55.8%, respectively. DR preceded MR, HDTVR, or LDTVR in each instance. The estimated 12 month probability of in-field and marginal control was 90.0%. Conclusion: Targeting areas at high-risk for occult disease with a lower radiation dose, while simultaneously boosting gross disease with HIGRT in patients with limited osseous and/or nodal metastases, has a high rate of treated metastasis control, a low rate of MR, acceptable toxicity, and high rate of pain palliation. Further investigation with prospective trials is warranted.
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    Knowledge-Based Statistical Inference Method for Plan Quality Quantification.
    (Technology in cancer research & treatment, 2019-01) Zhang, Jiang; Wu, Q Jackie; Ge, Yaorong; Wang, Chunhao; Sheng, Yang; Palta, Jatinder; Salama, Joseph K; Yin, Fang-Fang; Zhang, Jiahan
    AIM:The aim of the study is to develop a geometrically adaptive and statistically robust plan quality inference method. METHODS AND MATERIALS:We propose a knowledge-based plan quality inference method that references to similar plans in the historical database for patient-specific plan quality evaluation. First, a novel plan similarity metric with high-dimension geometrical difference quantification is utilized to retrieve similar plans. Subsequently, dosimetric statistical inferences are obtained from the selected similar plans. Two plan quality metrics-dosimetric result probability and dose deviation index-are proposed to quantify plan quality among prior similar plans. To evaluate the performance of the proposed method, we exported 927 clinically approved head and neck treatment plans. Eight organs at risk, including brain stem, cord, larynx, mandible, pharynx, oral cavity, left parotid and right parotid, were analyzed. Twelve suboptimal plans identified by dosimetric result probability were replanned to validate the capability of the proposed methods in identifying inferior plans. RESULTS:After replanning, left and right parotid median doses are reduced by 31.7% and 18.2%, respectively; 83% of these cases would not be identified as suboptimal without the proposed similarity plan selection. Analysis of population plan quality reveals that average parotid sparing has been improving significantly over time (21.7% dosimetric result probability reduction from year 2006-2007 to year 2016-2017). Notably, the increasing dose sparing over time in retrospective plan quality analysis is strongly correlated with the increasing dose prescription ratios to the 2 planning targets, revealing the collective trend in planning conventions. CONCLUSIONS:The proposed similar plan retrieval and analysis methodology has been proven to be predictive of the current plan quality. Therefore, the proposed workflow can potentially be applied in the clinics as a real-time plan quality assurance tool. The proposed metrics can also serve the purpose of plan quality analytics in finding connections and historical trends in the clinical treatment planning workflow.
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    Nonuniform Planning Target Volume Margins for Prostate Bed on the Basis of Surgical Clips on Daily Cone Beam Computed Tomography.
    (Advances in radiation oncology, 2019-01) Song, Haijun; Salama, Joseph K; Lee, William Robert; Wu, Qiuwen
    Purpose:We hypothesized that the interfraction motions of the superior and inferior prostate beds differ and therefore require different margins. In this study, we used daily cone beam computed tomography (CBCT) to evaluate the motion of postprostatectomy surgical clips (separated to superior and inferior portions) within the planning target volume (PTV) to derive data-driven PTV margins. Methods and Materials:Our study cohort included consecutive patients with identifiable surgical clips undergoing prostate bed irradiation with daily CBCT image guidance. We identified and contoured the clips within the PTV on the planning computed tomography and CBCT scans. All CBCT scans were registered to the planning computed tomography scan on the basis of pelvic bony structures. The superior border of the pubic symphysis was used to mark the division between the superior and inferior portions. Results:Eleven patients with 263 CBCT scans were included in the cohort. In the left-right direction, the global mean M, systematic error Σ, and residue error σ were 0.02, 0.03, and 0.16 cm, respectively, for superior clips, and 0.00, 0.03, and 0.03 cm, respectively, for inferior clips. In the anterior-posterior direction, the corresponding values were M = 0.01, Σ = 0.25, and σ= 0.37, respectively, for superior, and M = 0.08, Σ= 0.13, σ= 0.15, respectively, for inferior. In the superior-inferior direction, the values were M =-0.06, Σ= 0.23, and σ= 0.27, respectively, for superior, and M =-0.01, Σ= 0.21, σ= 0.20, respectively, for inferior. The results of the 2-tailed F tests showed that the anterior-posterior motion is statistically different between the superior and inferior portions in the anterior-posterior direction. There is no statistical difference in the superior-inferior and lateral directions. Therefore, we propose a set of nonuniform PTV margins (based on the formula 2.5 Σ+ 0.7σ) as 0.2 cm for all prostate beds in the left-right direction, 0.7 cm for all in superior-inferior, and 0.9 to 0.4 for superior-inferior in the anterior-posterior direction. Conclusions:The difference in motion between the superior and inferior portions of the prostate bed is statistically insignificant in the left-right and superior-inferior directions, but statistically significant in the anterior-posterior direction, which warrants a nonuniform PTV margin scheme.
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    The effect of MLC leaf width in single-isocenter multi-target radiosurgery with volumetric modulated arc therapy
    (Journal of Radiosurgery and SBRT, 2019-01-01) Abisheva, Zhanerke; Floyd, Scott R; Salama, Joseph K; Kirkpatrick, John; Yin, Fang-Fang; Moravan, Michael J; Giles, William; Adamson, Justus
    © 2019 Old City Publishing, Inc. Purpose: Single-isocenter multi-target (SIMT) volumetric modulated arc therapy (VMAT) is primarily limited to linear accelerators utilizing 2.5 mm leaf width MLCs. We explore feasibility of applying this technique to linear accelerators utilizing MLCs with leaf width of 5 mm. Methods: Twenty patients with 3-10 intracranial brain metastases originally treated with 2.5 mm MLCs were re-planned using 5 mm MLCs and relevant dosimetric indices were compared. We also evaluated various strategies of adding VMAT arcs to mitigate degradations of dose quality values. Results: Wider MLCs caused small changes in total MUs (5827 ± 2334 vs 5572 ± 2220, p = 0.006), and conformity index (CI) (2.22% ± 0.05%, p = 0.045), but produced more substantial increases in brain V30%[%] and V50%[%] (27.75% ± 0.16% and 20.04% ± 0.13% respectively, p < 0.001 for both), and V12Gy[cc] (16.91% ± 0.12%, p < 0.001). Conclusion: SIMT radiosurgery delivered via VMAT using 5 mm wide MLCs can achieve similar CI compared to that using 2.5 mm leaf width MLCs but with moderately increased isodose spill, which can be only partially mitigated by increasing the number of VMAT arcs.