Justus Adamson

Overview:

Radiosurgery and SBRT
Image Guided Radiation Therapy (IGRT)
Quality Assurance (QA) in Radiation Therapy
3D Dosimetry

Positions:

Associate Professor of Radiation Oncology

Radiation Oncology
School of Medicine

Member of the Duke Cancer Institute

Duke Cancer Institute
School of Medicine

Education:

Ph.D. 2009

Wayne State University

Research Assistant

William Beaumont Hospital Royal Oak

Postdoctoral Associate/Medical Physicist Residency Program, Radiation Oncology Physics Division

Duke University School of Medicine

Publications:

Feasibility of radiosurgery dosimetry using NIPAM 3D dosimeters and x-ray CT

© Published under licence by IOP Publishing Ltd. We investigated the feasibility of using N-isopropylacrylamide (NIPAM) dosimeters with x-ray CT to verify radiosurgery dose. Dosimeters were prepared at one facility and shipped to a second facility for irradiation. A simulation CT was acquired and plans prepared for a 4 field box, and a 4 arc VMAT radiosurgery plan to 6 targets with 1cm diameter. Each dosimeter was aligned via CBCT and irradiated, followed by 5 diagnostic CTs acquired after >24 hours, which were averaged for analysis. Absolute dose calibration was applied and dose evaluated for both plans. Hounsfield Units were proportional to dose above 10-12Gy. For the 4-field box, mean difference between measured and predicted dose >10Gy was -0.13Gy -1.69Gy and gamma index was <1 for 72% and 65% of voxels using a 5% / 1mm and 3% / 2mm criteria, respectively (threshold = 15Gy, global dose criteria). For the multifocal SRS case, mean dose within each target was within -0.14Gy- 0.55Gy of the expected value, and gamma index was < 1 for 94.0% and 99.5% of voxels, respectively (threshold = 15Gy). NIPAM based 3D dosimetry with x-ray CT is well suited for validating radiosurgery spatial alignment, as well as dose distributions when dose is above 10-12Gy.
Authors
Adamson, J; Carroll, J; Trager, M; Yoon, P; Kodra, J; Yin, FF; Maynard, E; Hilts, M; Oldham, M; Jirasik, A
MLA Citation
Adamson, J., et al. “Feasibility of radiosurgery dosimetry using NIPAM 3D dosimeters and x-ray CT.” Journal of Physics: Conference Series, vol. 1305, no. 1, 2019. Scopus, doi:10.1088/1742-6596/1305/1/012004.
URI
https://scholars.duke.edu/individual/pub1417159
Source
scopus
Published In
Journal of Physics: Conference Series
Volume
1305
Published Date
DOI
10.1088/1742-6596/1305/1/012004

Predicting intracranial progression following stereotactic radiosurgery for brain metastases: Implications for post SRS imaging

© 2019 Old City Publishing, Inc. Purpose: Follow-up imaging after stereotactic radiosurgery (SRS) is crucial to identify salvageable brain metastases (BM) recurrence. As optimal imaging intervals are poorly understood, we sought to build a predictive model for time to intracranial progression. Methods: Consecutive patients treated with SRS for BM at three institutions from January 1, 2002 to June 30, 2017 were retrospectively reviewed. We developed a model using stepwise regression that identified four prognostic factors and built a predictive nomogram. Results: We identified 755 patients with primarily non-small cell lung, breast, and melanoma BMs. Factors such as number of BMs, histology, history of prior whole-brain radiation, and time interval from initial cancer diagnosis to metastases were prognostic for intracranial progression. Per our nomogram, risk of intracranial progression by 3 months post-SRS in the high-risk group was 21% compared to 11% in the low-risk group; at 6 months, it was 43% versus 27%. Conclusion: We present a nomogram estimating time to BM progression following SRS to potentially personalize surveillance imaging.
Authors
Natarajan, BD; Rushing, CN; Cummings, MA; Jutzy, JMS; Choudhury, KR; Moravan, MJ; Fecci, PE; Adamson, J; Chmura, SJ; Milano, MT; Kirkpatrick, JP; Salama, JK
MLA Citation
Natarajan, B. D., et al. “Predicting intracranial progression following stereotactic radiosurgery for brain metastases: Implications for post SRS imaging.” Journal of Radiosurgery and Sbrt, vol. 6, no. 3, Jan. 2019, pp. 179–87.
URI
https://scholars.duke.edu/individual/pub1410083
Source
scopus
Published In
Journal of Radiosurgery and Sbrt
Volume
6
Published Date
Start Page
179
End Page
187

The effect of MLC leaf width in single-isocenter multi-target radiosurgery with volumetric modulated arc therapy.

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.
Authors
Abisheva, Z; Floyd, SR; Salama, JK; Kirkpatrick, J; Yin, F-F; Moravan, MJ; Giles, W; Adamson, J
MLA Citation
Abisheva, Zhanerke, et al. “The effect of MLC leaf width in single-isocenter multi-target radiosurgery with volumetric modulated arc therapy..” J Radiosurg Sbrt, vol. 6, no. 2, 2019, pp. 131–38.
URI
https://scholars.duke.edu/individual/pub1410134
PMID
31641549
Source
pubmed
Published In
J Radiosurg Sbrt
Volume
6
Published Date
Start Page
131
End Page
138

In Reply to Pratx and Kapp.

Authors
Oldham, M; Yoon, SW; Adamson, J; Zhang, X; Fecci, P; Dewhirst, M
MLA Citation
Oldham, Mark, et al. “In Reply to Pratx and Kapp..” Int J Radiat Oncol Biol Phys, vol. 101, no. 2, June 2018, pp. 495–96. Pubmed, doi:10.1016/j.ijrobp.2018.02.018.
URI
https://scholars.duke.edu/individual/pub1315738
PMID
29726370
Source
pubmed
Published In
Int J Radiat Oncol Biol Phys
Volume
101
Published Date
Start Page
495
End Page
496
DOI
10.1016/j.ijrobp.2018.02.018

Evaluating radiation-induced white matter changes in patients treated with stereotactic radiosurgery using diffusion tensor imaging: a pilot study.

Stereotactic radiosurgery (SRS) has been an effective treatment method for brain tumors; however, few data are available regarding radiation-induced white matter (WM) damage by SRS. In this work, diffusion tensor imaging (DTI) was used to investigate WM changes following SRS. Fifteen patients with gliomas were enrolled, with prescription doses ranging 18-25 Gy. Patients were scanned with magnetic resonance imaging (MRI) including DTI before and after SRS. Diffusion tensors were calculated and fiber tracking was performed. Non-irradiated WM volumes and irradiated WM volumes receiving ≥ 12 Gy and ≥ Gy were contoured as volumes of interest (VOI). Apparent diffusion coefficient (〈D〉), fractional anisotropy (FA) and number of fibers (NF) were calculated and assessed using the Wilcoxon signed-rank test. Compared with those of non-irradiated VOIs, FA and NF decreased considerably after two months of SRS in the irradiated WM VOIs. The variation in (〈D〉 was however small and was not statistically significant. The preliminary results suggested that FA and NF might potentially be more sensitive indicators than (〈D〉 in measuring radiation-induced WM changes and DTI could be a valuable tool to assess radiation-induced WM changes in SRS. Although it is still preliminary, this pilot study may be useful to provide insights for future studies.
Authors
MLA Citation
Chang, Zheng, et al. “Evaluating radiation-induced white matter changes in patients treated with stereotactic radiosurgery using diffusion tensor imaging: a pilot study..” Technol Cancer Res Treat, vol. 13, no. 1, Feb. 2014, pp. 21–28. Pubmed, doi:10.7785/tcrt.2012.500358.
URI
https://scholars.duke.edu/individual/pub958763
PMID
23862743
Source
pubmed
Published In
Technology in Cancer Research & Treatment
Volume
13
Published Date
Start Page
21
End Page
28
DOI
10.7785/tcrt.2012.500358