Resident, Thomas Jefferson University Hospital, Medical Physics (2021)
PhD, SUNY at Buffalo, Buffalo, NY, Medical Physics (2019)
MS, SUNY at Buffalo, Buffalo, NY, Biophysics (2015)
BS, The Catholic University of America, Washington, DC, Physics (2013)
Assistant Professor (CHS), Department of Human Oncology (2021)
Selected Honors and Awards
CUA Alumni Success Story (2014)
Honors Degree in Humanities (2013)
Sigma Pi Sigma (2012-present)
Boards, Advisory Committees and Professional Organizations
American Association of Physicist in Medicine (AAPM)
Improved dose homogeneity using electronic compensation technique for total body irradiation Journal of applied clinical medical physics
Tyson TE, Podgorsak MB, Singh AK, Wang IZ
2018 May;19(3):159-167. doi: 10.1002/acm2.12316. Epub 2018 Apr 14.
In total body irradiation (TBI) utilizing large parallel-opposed fields, the manual placement of lead compensators has conventionally been used to compensate for the varying thickness throughout the body. The goal of this study is to pursue utilizing the modern electronic compensation (E-comp) technique to more accurately deliver dose to TBI patients. Bilateral parallel-opposed TBI treatment plans were created using E-comp for 15 patients for whom CT data had been previously acquired. A desirable fluence pattern was manually painted within each field to yield a uniform dose distribution. The conventional compensation technique was simulated within the treatment planning system (TPS) using a field-in-field (FIF) method. This allows for a meaningful evaluation of the E-comp technique in comparison to the conventional method. Dose-volume histograms (DVH) were computed for all treatment plans. The mean total body dose using E-comp deviates from the prescribed dose (4 Gy) by an average of 2.4%. The mean total body dose using the conventional compensation deviates from the prescribed dose by an average of 4.5%. In all cases, the mean body dose calculated using E-comp technique deviates less than 10% from that of conventional compensation. The average reduction in maximum dose using E-comp compared to that of the conventional method was 30.3% ± 6.6% (standard deviation). In all cases, the s-index for the E-comp technique was lower (10.5% ± 0.7%) than that of the conventional method (15.8% ± 4.4%), indicating a more homogenous dose distribution. In conclusion, a large reduction in maximum body dose can be seen using the proposed E-comp technique while still producing a mean body dose that accurately complies with the prescription dose. Dose homogeneity was quantified using s-index which demonstrated a reduction in hotspots with E-comp technique. Electronic compensation technique is capable of more accurately delivering a total body dose compared to conventional methods.
PMID:29654662 | PMC:PMC5978698 | DOI:10.1002/acm2.12316
View details for PubMedID 29654662
TBI lung dose comparisons using bilateral and anteroposterior delivery techniques and tissue density corrections Journal of applied clinical medical physics
Bailey DW, Wang IZ, Lakeman T, Hales LD, Singh AK, Podgorsak MB
2015 Mar 8;16(2):5293. doi: 10.1120/jacmp.v16i2.5293.
This study compares lung dose distributions for two common techniques of total body photon irradiation (TBI) at extended source-to-surface distance calculated with, and without, tissue density correction (TDC). Lung dose correction factors as a function of lateral thorax separation are approximated for bilateral opposed TBI (supine), similar to those published for anteroposterior-posteroanterior (AP-PA) techniques in AAPM Report 17 (i.e., Task Group 29). 3D treatment plans were created retrospectively for 24 patients treated with bilateral TBI, and for whom CT data had been acquired from the head to the lower leg. These plans included bilateral opposed and AP-PA techniques- each with and without - TDC, using source-to-axis distance of 377 cm and largest possible field size. On average, bilateral TBI requires 40% more monitor units than AP-PA TBI due to increased separation (26% more for 23 MV). Calculation of midline thorax dose without TDC leads to dose underestimation of 17% on average (standard deviation, 4%) for bilateral 6 MV TBI, and 11% on average (standard deviation, 3%) for 23 MV. Lung dose correction factors (CF) are calculated as the ratio of midlung dose (with TDC) to midline thorax dose (without TDC). Bilateral CF generally increases with patient separation, though with high variability due to individual uniqueness of anatomy. Bilateral CF are 5% (standard deviation, 4%) higher than the same corrections calculated for AP-PA TBI in the 6 MV case, and 4% higher (standard deviation, 2%) for 23 MV. The maximum lung dose is much higher with bilateral TBI (up to 40% higher than prescribed, depending on patient anatomy) due to the absence of arm tissue blocking the anterior chest. Dose calculations for bilateral TBI without TDC are incorrect by up to 24% in the thorax for 6 MV and up to 16% for 23 MV. Bilateral lung CF may be calculated as 1.05 times the values published in Table 6 of AAPM Report 17, though a larger patient pool is necessary to better quantify this trend. Bolus or customized shielding will reduce lung maximum dose in the anterior thorax.
PMID:26103198 | PMC:PMC5690074 | DOI:10.1120/jacmp.v16i2.5293
View details for PubMedID 26103198
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