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:

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

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

Adaptive planning using positron emission tomography for locally advanced lung cancer: A feasibility study.

PURPOSE: To evaluate the feasibility of adaptive planning using positron emission tomography-computed tomography (PET-CT) in locally advanced non-small cell lung cancer. METHODS AND MATERIALS: Patients with locally advanced non-small cell lung cancer receiving definitive radiation therapy (RT) were eligible. Initial planning PET-CT was performed and a conventional RT plan (2 Gy/fraction to 60 Gy) was designed. A second planning PET-CT was obtained at ~50 Gy. Dose escalation to ~70 Gy for residual fludeoxyglucose-avid disease was pursued at the discretion of the treating oncologists. The primary endpoint was feasibility of adaptive planning using interim PET-CT. Normal tissue dose-volume parameters were calculated for both adaptive and simulated nonadaptive plans. RESULTS: From 2012 to 2014, 33 eligible patients were enrolled and underwent planning PET-CT, 3 of which were found to have new distant metastases. Of 30 patients who initiated RT, interim PET-CT was obtained in 29. This showed complete response in 2 patients, partial response/stable disease in 24, and new distant metastases in 3. Selective dose escalation was performed in 17 patients. For those receiving a boost, the median gross tumor volumes pre-RT and at ~50 Gy were 78 mL and 29 mL, respectively (P = .01). Reasons for no dose escalation were normal tissue constraints (n = 3), poorly defined residual disease (n = 2), acute toxicity (n = 1), and refusal of further therapy (n = 1). Adaptive planning compared with a simulated nonadaptive approach allowed for significant dose reductions to the lungs, heart, and esophagus (all P < .01). CONCLUSIONS: Adaptive planning using PET-CT was feasible and allows for significant dose reductions to normal tissues compared with traditional planning techniques.
Authors
Kelsey, CR; Christensen, JD; Chino, JP; Adamson, J; Ready, NE; Perez, BA
MLA Citation
Kelsey, Chris R., et al. “Adaptive planning using positron emission tomography for locally advanced lung cancer: A feasibility study..” Pract Radiat Oncol, vol. 6, no. 2, Mar. 2016, pp. 96–104. Pubmed, doi:10.1016/j.prro.2015.10.009.
URI
https://scholars.duke.edu/individual/pub1112754
PMID
26723555
Source
pubmed
Published In
Pract Radiat Oncol
Volume
6
Published Date
Start Page
96
End Page
104
DOI
10.1016/j.prro.2015.10.009

Independent verification of gantry angle for pre-treatment VMAT QA using EPID.

We propose a method to incorporate independent verification of gantry angle for electronic portal imaging device (EPID)-based pre-treatment quality assurance (QA) of clinical volumetric modulated arc therapy (VMAT) plans. Gantry angle is measured using projections in the EPID of a custom phantom placed on the couch and the treatment plan is modified so as to be incident on the phantom with a portion of the beam that is collimated in the clinical plan. For our implementation, collimator and couch angles were set to zero and the inferior jaw and two most inferior multi-leaf collimator pairs were opened for the entire QA delivery. A phantom containing five gold coils was used to measure the gantry rotation through which each portal image was acquired. We performed the EPID QA for ten clinical plans and evaluated accuracy of gantry angle measurement, scatter incident on the imager due to the phantom, inter-image pixel linearity and inter- and intra-image noise. The gantry angle could be measured to within 0.0 ± 0.3° for static gantry and 0.2 ± 0.2° for arc acquisitions. Scatter due to the presence of the phantom was negligible. The procedure was shown to be feasible and adds gantry angle to the treatment planning parameters that can be verified by EPID-based pre-treatment VMAT QA.
Authors
Adamson, J; Wu, Q
MLA Citation
Adamson, Justus, and Qiuwen Wu. “Independent verification of gantry angle for pre-treatment VMAT QA using EPID..” Phys Med Biol, vol. 57, no. 20, Oct. 2012, pp. 6587–600. Pubmed, doi:10.1088/0031-9155/57/20/6587.
URI
https://scholars.duke.edu/individual/pub744649
PMID
23010739
Source
pubmed
Published In
Phys Med Biol
Volume
57
Published Date
Start Page
6587
End Page
6600
DOI
10.1088/0031-9155/57/20/6587

SU‐GG‐T‐483: Does Breath‐Hold Immobilization Affect Tumor Radioresistance in Breast?

Purpose: A 15–30s Breath Hold (BH) is often used in radiation therapy for breast cancer patients to minimize heart dose, however its effect on tumor oxygenation and radiosensitivity is unknown. The purpose of this study is to utilize published data on the physiological changes induced by BH to predict the effect of BH on breast tumor oxygenation and radiosensitivity. Methods and Materials: We utilized the arterial hemoglobin de‐saturation of oxygen due to BH measured by Ferretti et al. (J Appl Physiol, 1991) to calculate arterial oxygen tension before and after BHs of 30, 60, 90, 120, and 150s. The change in tissue oxygenation due to BH was then estimated by modifying the pO2 distribution for breast tumor measured by Vaupel et al. (Wien Med Wochenschr, 2002) according to the relationship expected from the Krogh oxygen diffusion model assuming either a constant oxygen consumption rate, or that the hypoxic fraction remains unchanged. Finally, the mean Oxygen Enhancement Ratio (OER) was calculated before and after BH. Results: Before BH, the mean tumor OER was 2.2 (standard deviation = 0.2). For a 30s BH, the mean OER decreased to 2.1 (standard deviation = 0.2) assuming a constant hypoxic fraction and to 1.6 (standard deviation = 0.3) assuming a constant oxygen consumption rate. The percent decrease in mean OER after BHs of 30, 60, 90, 120, and 150s was 4%, 6%, 9%, 10%, and 12% assuming a constant hypoxic fraction, and was 29%, 37%, 40%, 41%, and 42% assuming a constant oxygen consumption rate. Conclusion: De‐saturation of arterial oxygen during a 30s BH may cause a reduction in mean tumor OER of between 4–29%. However analysis with additional parameters and experimental validation is required and will provide added insight into effects of BH. © 2010, American Association of Physicists in Medicine. All rights reserved.
Authors
Adamson, J; Kirkpatrick, J; Yin, F
MLA Citation
Adamson, J., et al. “SU‐GG‐T‐483: Does Breath‐Hold Immobilization Affect Tumor Radioresistance in Breast?.” Medical Physics, vol. 37, no. 6, 2010. Scopus, doi:10.1118/1.3468881.
URI
https://scholars.duke.edu/individual/pub1266161
Source
scopus
Published In
Medical Physics
Volume
37
Published Date
Start Page
3298
DOI
10.1118/1.3468881