Columbus Regional Healthcare System

Coronary artery thrombosis is a phenomenon physicians have studied throughout the years. The different risk factors that play a role in the formation of an atherosclerotic plaque leading to coronary artery blockage are vast and can affect the patient significantly if not examined and diagnosed carefully. The objective of this case report is to highlight this unusual occurrence of repeated coronary artery thrombosis. A 54-year-old Caucasian female presented to the emergency department with a one-day history of sharp chest pain in the substernal area that radiated between her shoulder blades and left arm. Despite being on dual antiplatelet therapy, an electrocardiogram (ECG) showed an inferior ST-elevation myocardial infarction (STEMI). Her medical history was extensive with factor V Leiden deficiency, hyperhomocysteinemia, recurrent deep vein thrombosis (DVT), and a family history of myocardial infarction. The patient was taken to the cardiac catheterization lab based on these characteristics. The patient was diagnosed with a 100% thrombosis in the distal right coronary artery (RCA), which was stented nine months before this current presentation. The patient had been compliant with all her medications from her previous stent placement. A new drug-eluting stent (DES) was inserted, and the patient was placed on prasugrel and apixaban. This was a very interesting topic for a case report due to the time frame of repeat thrombosis in a coronary artery with a DES and the patient’s underlying hypercoagulable state. There are few cases of same vessel restenosis post-DES placement. Our case highlights the need for further research into the prevalence of genetic risk factors in coronary artery thrombosis and the need to investigate the efficacy of different anticoagulation therapies in patients with factor V Leiden thrombophilia.

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Abstract ObjectiveTo assess the feasibility of using synthetic computed tomography for treatment planning of the dominant intraprostatic lesion (DIL), a high‐risk region of interest that offers potential for increased local tumor control.MethodsA dosimetric study was performed on 15 prostate cancer patients with biopsy‐proven prostate cancer who had undergone magnetic resonance imaging. DILs were contoured based on the turbo spin echo T2‐weighted and diffusion weighted images. Air, bone, fat, and soft tissue were segmented and assigned bulk‐density HU values of –1000, 285, –50, and 40, respectively, to create a synthetic computed tomography. Simultaneous integrated boost (SIB) and standard treatment plans were created for each patient. The total dose was 79.2 Gy to the non‐boosted planning target volume for both plans with a boost of 100 Gy for the DIL in the SIB plan. A radiobiological model was created to determine individualized dose–response curves based on the patient's apparent diffusion coefficient maps.ResultsMean doses to the non‐boost planning target volume were 81.2 ± 0.3 Gy with the SIB and 81.0 ± 0.4 Gy without. For the DIL, the boosted mean dose was 102.6 ± 0.6 Gy. Total motor unit was 860 ± 100 with the SIB and 730 ±100 without. Femoral heads, rectum, bladder, and penile bulb were within established dose guidelines for either treatment technique. The average tumor control probability was 94% with the SIB compared with 78% without boosting the DIL.ConclusionThis study showed the feasibility of magnetic resonance imaging‐only treatment planning for patients with prostate cancer with a SIB to the DIL. DIL dose can be escalated to 100 Gy on synthetic computed tomography, while maintaining the original 79.2 Gy prescription dose and the organ of interest clinical dose limits.

Purpose:The ultimate goal of radiotherapy treatment planning is to find a treatment that will yield a high tumor‐control‐probability(TCP) with an acceptable normal‐tissue‐complication probability(NTCP). Yet most treatment planning today is not based upon optimization of TCPs and NTCPs, but rather upon meeting physical dose and volume constraints defined by the planner. We design treatment plans that optimize TCP directly and contrast them with the clinical dose‐based plans. PET image is incorporated to evaluate gain in TCP for dose escalation.Methods:We build a nonlinear mixed integer programming optimization model that maximizes TCP directly while satisfying the dose requirements on the targeted organ and healthy tissues. The solution strategy first fits the TCP function with a piecewise‐linear approximation, then solves the problem that maximizes the piecewise linear approximation of TCP, and finally performs a local neighborhood search to improve the TCP value. To gauge the feasibility, characteristics, and potential benefit of PET‐image guided dose escalation, initial validation consists of fifteen cervical cancer HDR patient cases. These patients have all received prior 45Gy of external radiation dose. For both escalated strategies, we consider 35Gy PTV‐dose, and two variations (37Gy‐boost to BTV vs 40Gy‐boost) to PET‐image‐pockets.Results:TCP for standard clinical plans range from 59.4% ‐ 63.6%. TCP for dose‐based PET‐guided escalated‐dose‐plan ranges from 63.8%–98.6% for all patients; whereas TCP‐optimized plans achieves over 91% for all patients. There is marginal difference in TCP among those with 37Gy‐boosted vs 40Gy‐boosted. There is no increase in rectum and bladder dose among all plans.Conclusion:Optimizing TCP directly results in highly conformed treatment plans. The TCP‐optimized plan is individualized based on the biological PET‐image of the patients. The TCP‐optimization framework is generalizable and has been applied successfully to other external‐beam delivery modalities. A clinical trial is on‐going to gauge the clinical significance.Partially supported by the National Science Foundation.

Purpose: To verify dose delivered with HDR Accuboost applicators using TLD, ion chamber and Gafchromic film measurements and to examine applicator leakage. Methods: A microSelectron HDR unit was used to deliver a dose of 50cGy to the mid-plane of a 62mm thick solid water phantom using dwell times from Monte Carlo pre-calculated nomograms for a 60mm, 70mm Round and 60mm Skin-Dose Optimized (SDO) applicators respectively. GafChromic EBT3+ film was embedded in the phantom midplane horizontally to measure dose distribution. Absolute dose was also measured with TLDs and an ADCL calibrated parallel-plate ion chamber placed in the film plane at field center for each applicator. The film was calibrated using 6MV x-ray beam. TLDs were calibrated in a Cs-137 source at UW-Madison calibration laboratory. Radiation leakage through the tungsten alloy shell was measured with a film wrapped around outside surface of a 60mm Round applicator. Results: Measured maximum doses at field center are consistently lower than predicated by 5.8% for TLD, 8.8% for ion chamber, and 2.6% for EBT3+ film on average, with measurement uncertainties of 2.2%, 0.3%, and 2.9% for TLD, chamber, film respectively. The total standard uncertainties for ion chamber and Gafchromic film measurement are 4.9% and 4.6% respectively[1]. The area defined by the applicator aperture was covered by 80% of maximum dose for 62mm compression thickness. When 100cGy is delivered to mid-plane with a 60mm Round applicator, surface dose ranges from 60cGy to a maximum of 145cGy, which occurs at source entrance to the applicator. Conclusion: Measured doses by all three techniques are consistently lower than predicted in our measurements. For a compression thickness of 62 mm, the field size defined by the applicator is only covered by 80% of prescribed dose. Radiation leakage of up to 145cGy was found at the source entrance of applicators.

Background The Acute Ischemic Stroke (AIS) process of care in the emergency department (ED) continues to evolve with interventions that help expedite administration of tPA and decrease “Door-to-Needle” (DTN) time and the burden associated with AIS. We hypothesized that redesigning the ED stroke process using selected best practice strategies would increase the percentage of patients receiving tPA in under 60 minutes, increase the percentage of patients treated with tPA within 4.5 hours, decrease the mean DTN time, and increase the percentage of stroke code activations (Code S) that occur in under 15 minutes. The variables implemented in the AIS process were analyzed for correlation of impact on decreasing DTN time. Methods The team mapped current AIS processes and developed an initiative to redesign the process including developing an AIS treatment room, a “stroke clot box” for storing and mixing tPA at bedside, and NIHSS certification of leadership staff. Multiple regression analysis of the correlation of these strategies as well as the presence of an in-house neurologist and EMS pre-notification on DTN time was performed. Results The initiatives increased the percentage of AIS patients treated with tPA within 4.5 hours from 67% to 100%. AIS patients treated under 60 minutes increased from 50% to 65%. The mean DTN time has decreased from 88.4 to 54.1 minutes. Of patients treated with tPA under 60 minutes (n=11) the mean DTN time was 40.6 minutes (lowest DTN time of 24 minutes). Code S activations within 15 minutes increased by 14 % to 47.8%. Multiple Regression analysis revealed that the presence of an in-house neurologist had the highest correlation (β=0.810, p=0.001) with lower DTN times, followed by using a "stroke clot box" (β=0.631, p=0.008) and a dedicated AIS treatment room (β=0.244, p=0.03). EMS pre-notification was done for nearly every tPA treated patient and its impact was therefore negligible (β=0.05, p=0.2). Conclusions These initiatives increased the number of patients treated, decreased mean DTN time, and increased the percentage of tPA eligible AIS patients within 60 minutes. An in-house neurologist, tPA at bedside, and a dedicated treatment room correlate with lower DTN times and therefore advance best practice for acute stroke care.