Implementation of a Stereoscopic Camera System for Clinical Electron Simulation and Treatment Planning.

PURPOSE: A 3-dimensinal (3D) stereoscopic camera system developed by .decimal was commissioned and implemented into the clinic to improve the efficiency of clinical electron simulations. Capabilities of the camera allowed simulations to be moved from the treatment vault into any room with a flat surface that could accommodate patient positioning devices, eliminating the need for clinical patient setup timeslots on the treatment machine. This work describes the process used for these simulations and compares the treatment parameters determined by the system to those used in delivery. METHODS AND MATERIALS: The Decimal3D scanner workflow consisted of: scanning the patient surface; contouring the treatment area; determining gantry, couch, collimator, and source-to-surface distance (SSD) parameters for en face entry of the beam with sufficient clearance at the machine; and ordering custom electron cutouts when needed. Transparencies showing the projection of in-house library cutouts at various clinical SSDs were created to assist in choosing an appropriate library cutout. Data from 73 treatment sites were analyzed to evaluate the accuracy of the scanner-determined beam parameters for each treatment delivery. RESULTS: Clinical electron simulations for 73 treatment sites, predominately keloids, were transitioned out of the linear accelerator (LINAC) vault using the new workflow. For all patients, gantry, collimator, and couch parameters, along with SSD and cone size, were determined using the Decimal3D scanner with 57% of simulations using library cutouts. Tolerance tables for patient setup were updated to allow differences of 10, 20, and 5° for gantry, collimator, and couch, respectively. Approximately 7% of fractions (N = 181 total fractions) were set up outside of the tolerance table based on physician direction during treatment. This reflects physician preference to adjust the LINAC rather than patient position during treatment setup. No scanner-derived plan was untreatable because of cutout shape inaccuracy or clearance issues. CONCLUSIONS: Clinical electron simulations were successfully transitioned out of the LINAC vault using the Decimal3D scanner without loss of setup accuracy, as measured through machine parameter determination and electron cutout shape.

Accelerated partial breast irradiation in early stage breast cancer.

Accelerated partial breast irradiation (APBI) is increasingly used to treat select patients with early stage breast cancer. However, radiation technique, dose and fractionation as well as eligibility criteria differ between studies. This has led to controversy surrounding appropriate patients for APBI and an assessment of the toxicity and cosmetic outcomes of APBI as compared to whole breast irradiation (WBI). This paper reviews existing data for APBI, APBI delivery at our institution, and ongoing research to better define patient selection, treatment delivery, dosimetric considerations and toxicity outcomes.

Five-Fraction Prone Accelerated Partial Breast Irradiation: Long-Term Oncologic, Dosimetric, and Cosmetic Outcome.

PURPOSE: Randomized data support accelerated partial breast irradiation (APBI) for early-stage breast cancer with variable techniques and cosmesis outcomes. We have treated patients with 5-fraction prone external beam APBI for over a decade and herein report acute and late outcomes. METHODS AND MATERIALS: Patients receiving APBI 600 cGy × 5 between 2010 and 2019 were included. APBI was primarily delivered prone, with opposed tangents targeting the tumor bed expanded by 1.5 cm (cropped 6 mm from skin). Ipsilateral breast was constrained to V50% < 60% and V100% < 35%. Survival was estimated with Kaplan-Meier. Late toxicities and clinician- and patient-rated cosmesis were evaluated for patients with >6 months follow-up (FU). RESULTS: Of 345 patients meeting criteria, 14 were excluded due to APBI given for ipsilateral breast tumor recurrence (IBTR; n = 3), palliation (n = 9), and incomplete radiation therapy course (n = 2). Of the 331 remaining, median age was 70, 7.2% had ductal carcinoma in situ, and 94.3% were treated prone, with 32% treated every other day and 68% on consecutive days. Mean heart dose was 23.8 cGy for left-sided and 12.7 cGy for right-sided cancers. Ipsilateral lung V30% was 0.4%. At 5-year median FU, there were 7 (2.1%) IBTR, 9 (2.7%) contralateral recurrences, and 1 (0.3%) distant metastasis. Five-year local recurrence-free, disease-free, and overall survival was 99.5%, 96.7%, and 98.1%, respectively. When comparing patients with IBTR versus without, a higher proportion did not receive hormone therapy (71.4% vs. 26.2%, P = .018). Rates of acute grade 1 to 2 dermatitis, fatigue, and pain were 35.4%, 21.8%, and 9.4%, respectively, with no grade 3 toxicity. The rate of good-excellent physician- and patient-rated cosmesis (n = 199, median FU 2.8 years) was 92.5% and 89.4%, respectively. Patients experienced low rates of telangiectasia, fibrosis, and retraction/atrophy. CONCLUSIONS: We report excellent dosimetric, oncologic, cosmetic, and late toxicity outcomes for patients treated with 5-fraction APBI. To our knowledge this is the largest series of women treated with prone APBI.

Automatic treatment planning for VMAT-based total body irradiation using Eclipse scripting.

The purpose of this work is to establish an automated approach for a multiple isocenter volumetric arc therapy (VMAT)-based TBI treatment planning approach. Five anonymized full-body CT imaging sets were used. A script was developed to automate and standardize the treatment planning process using the Varian Eclipse v15.6 Scripting API. The script generates two treatment plans: a head-first VMAT-based plan for upper body coverage using four isocenters and a total of eight full arcs; and a feet-first AP/PA plan with three isocenters that covers the lower extremities of the patient. PTV was the entire body cropped 5 mm from the patient surface and extended 3 mm into the lungs and kidneys. Two plans were generated for each case: one to a total dose of 1200 cGy in 8 fractions and a second one to a total dose of 1320 cGy in 8 fractions. Plans were calculated using the AAA algorithm and 6 MV photon energy. One plan was created and delivered to an anthropomorphic phantom containing 12 OSLDs for in-vivo dose verification. For the plans prescribed to 1200 cGy total dose the following dosimetric results were achieved: median PTV V100% = 94.5%; median PTV D98% = 89.9%; median lungs Dmean = 763 cGy; median left kidney Dmean = 1058 cGy; and median right kidney Dmean = 1051 cGy. For the plans prescribed to 1320 cGy total dose the following dosimetric results were achieved: median PTV V100% = 95.0%; median PTV D98% = 88.7%; median lungs Dmean = 798 cGy; median left kidney Dmean = 1059 cGy; and median right kidney Dmean = 1064 cGy. Maximum dose objective was met for all cases. The dose deviation between the treatment planning dose and the dose measured by the OSLDs was within ±4%. In summary, we have demonstrated that scripting can produce high-quality plans based on predefined dose objectives and can decrease planning time by automatic target and optimization contours generation, plan creation, field and isocenter placement, and optimization objectives setup.

CBCT image quality QA: Establishing a quantitative program.

PURPOSE: Routine quality assurance (QA) of cone-beam computed tomography (CBCT) scans used for image-guided radiotherapy is prescribed by the American Association of Physicists in Medicine Task Group (TG)-142 report. For CBCT image quality, TG-142 recommends using clinically established baseline values as QA tolerances. This work examined how image quality parameters vary both across machines of the same model and across different CBCT techniques. Additionally, this work investigated how image quality values are affected by imager recalibration and repeated exposures during routine QA. METHODS: Cone-beam computed tomography scans of the Catphan 604 phantom were taken on four TrueBeam® and one Edge™ linear accelerator using four manufacturer-provided techniques. TG-142 image quality parameters were calculated for each CBCT scan using SunCHECK Machine™. The variability of each parameter with machine and technique was evaluated using a two-way ANOVA test on a dataset consisting of 200 CBCT scans. The impact of imager calibration on image quality parameters was examined for a subset of three machines using an unpaired Student's t-test. The effect of artifacts appearing on CBCTs taken in rapid succession was characterized and an approach to reduce their appearance was evaluated. Additionally, a set of baselines and tolerances for all image quality metrics was presented. RESULTS: All imaging parameters except geometric distortion varied with technique (P < 0.05) and all imaging parameters except slice thickness varied with machine (P < 0.05). Imager calibration can change the expected value of all imaging parameters, though it does not consistently do so. While changes are statistically significant, they may not be clinically significant. Finally, rapid acquisition of CBCT scans can introduce image artifacts that degrade CBCT uniformity. CONCLUSIONS: This work characterized the variability of acquired CBCT data across machines and CBCT techniques along with the impact of imager calibration and rapid CBCT acquisition on image quality.

Effect of goal-directed therapy on post-operative neutrophil gelatinase-associated lipocalin profile in patients undergoing on-pump coronary artery surgery.

PURPOSE: Neutrophil gelatinase-associated lipocalin (NGAL) is an early biomarker of acute kidney injury (AKI). Goal-directed therapy (GDT) in on-pump coronary artery bypass grafting (CABG) has been associated with lower post-operative NGAL levels in recent studies. The present study aimed at comparing plasma (P) and urinary (U)-NGAL levels following the use of GDT versus conventional haemodynamic therapy (CT) in patients undergoing on-pump CABG. METHODS: A prospective randomised controlled study conducted in a single university hospital. A total of 54 patients in the GDT group and 56 patients in CT group after exclusions. RESULTS: U-NGAL was significantly lower immediately post-surgery (T 1) in GDT group (25.11 ± 1.5 versus 27.80 ± 1.7 µg/L; p < 0.001) and at 4 h (T 2) (38.19 ± 23.6 versus 52.30 ± 28.3 µg/L; p = 0.006) and at 24 h post-operatively (T 3) (34.85 ± 14 versus 39.7 ± 11.1 µg/L; p = 0.047). P-NGAL was comparable between groups at T 1 but lower in the GDT group at T 2 (92.81 ± 4.8 versus 94.77 ± 4.5 µg/L; p = 0.03) and T 3 (67.44 ± 3.7 versus 75.96 ± 5.3 µg/L; p < 0.001). U-NGAL levels correlated well with the peak post-operative creatinine as compared to P-NGAL. On-pump patients manifest neutrophil activation, accounting for comparable levels of P-NGAL in the two groups at T 1. GDT-based haemodynamic management resulted in lower U-NGAL levels at T 1, T 2 and T 3 and lower P-NGAL levels at T 2 and T 3. CONCLUSIONS: Haemodynamic optimisation with GDT prevents further renal insult initiated with the inflammatory activation with cardiopulmonary bypass (CPB), as evidenced by lower post-operative U-NGAL levels.

Goal-directed therapy improves the outcome of high-risk cardiac patients undergoing off-pump coronary artery bypass.

BACKGROUND: There has been a constant emphasis on developing management strategies to improve the outcome of high-risk cardiac patients undergoing surgical revascularization. The performance of coronary artery bypass surgery on an off-pump coronary artery bypass (OPCAB) avoids the risks associated with extra-corporeal circulation. The preliminary results of goal-directed therapy (GDT) for hemodynamic management of high-risk cardiac surgical patients are encouraging. The present study was conducted to study the outcome benefits with the combined use of GDT with OPCAB as compared to the conventional hemodynamic management. MATERIAL AND METHOD: Patients with the European System for Cardiac Operative Risk Evaluation ≥3 scheduled for OPCAB were randomly divided into two groups; the control and GDT groups. The GDT group included the monitoring and optimization of advanced parameters, including cardiac index (CI), systemic vascular resistance index, oxygen delivery index, stroke volume variation; continuous central venous oxygen saturation (ScVO 2 ), global end-diastolic volume, and extravascular lung water (EVLW), using FloTrac™ , PreSep™ , and EV-1000 ® monitoring panels, in addition to the conventional hemodynamic management in the control group. The hemodynamic parameters were continuously monitored for 48 h in Intensive Care Unit (ICU) and corrected according to GDT protocol. A total of 163 patients consented for the study. RESULT: Seventy-five patients were assigned to the GDT group and 88 patients were in the control group. In view of 9 exclusions from the GDT group and 12 exclusions from control group, 66 patients in the GDT group and 76 patients in control group completed the study. CONCLUSION: The length of stay in hospital (LOS-H) (7.42 ± 1.48 vs. 5.61 ± 1.11 days, P < 0.001) and ICU stay (4.2 ± 0.82 vs. 2.53 ± 0.56 days, P < 0.001) were significantly lower in the GDT group as compared to control group. The duration of inotropes (3.24 ± 0.73 vs. 2.89 ± 0.68 h, P = 0.005) was also significantly lower in the GDT group. The two groups did not differ in duration of ventilated hours, mortality, and other complications. The parameters such as ScVO 2 , CI, and EVLW had a strong negative and positive correlation with the LOS-H with r values of - 0.331, -0.319, and 0.798, respectively. The study elucidates the role of a goal-directed hemodynamic optimization for improved outcome in high-risk cardiac patients undergoing OPCAB.

Serum albumin perturbations in cyanotics after cardiac surgery: Patterns and predictions.

INTRODUCTION: Hypoalbuminemia is a well-recognized predictor of general surgical risk and frequently occurs in patients with cyanotic congenital heart disease (CCHD). Moreover, cardiopulmonary bypass (CPB)-induced an inflammatory response, and the overall surgical stress can effect albumin concentration greatly. The objective of his study was to track CPB-induced changes in albumin concentration in patients with CCHD and to determine the effect of hypoalbuminemia on postoperative outcomes. MATERIALS AND METHODS: Prospective observational study conducted in 150 patients, Group 1 ≤18 years (n = 75) and Group 2 >18 years (n = 75) of age. Albumin levels were measured preoperatively (T1), after termination of CPB (T2) and 48 h post-CPB (T3). Primary parameters (mortality, duration of postoperative ventilation, duration of inotropes and duration of Intensive Care Unit [ICU] stay) and secondary parameters (urine output, oliguria, arrhythmias, and hemodynamic parameters) were recorded. RESULTS: The albumin levels in Group 1 at T1, T2, and T3 were 3.8 ± 0.48, 3.2 ± 0.45 and 2.6 ± 0.71 mg/dL; and in Group 2 were 3.7 ± 0.50, 3.2 ± 0.49 and 2.7 ± 0.62 mg/dL respectively. All patients showed a significant decrease in albumin concentration 48 h after surgery (P < 0.01). Analysis between the groups, however, showed no statistical difference. Eleven patients expired during the study period, and nonsurvivors showed significantly lower serum albumin concentration 48 h after surgery 2.3 ± 0.62 mg/dL versus 3.7 ± 0.56 mg/dL in the survivors (P < 0.05). Receiver operating characteristic curve showed that a baseline albumin cut-off value of 3.3 g/dL predicts mortality with a positive predictive value 47.6% and a negative predictive value of 99.2% (P < 0.05). A strong correlation was seen between albumin levels at 48 h with duration of CPB (r2 = 0.6321), ICU stay (r2 = 0.7447) and incidence of oliguria (r2 = 0.8803). CONCLUSIONS: The study demonstrated similar fall in albumin concentration in cyanotic patients (both adult and pediatric) in response to CPB. Low preoperative serum albumin concentrations (<3.3 g/dL) can be used to identify and prognosticate subset of cyanotics predisposed to additional surgical risk.

Prevalence of carotid artery stenosis in neurologically asymptomatic patients undergoing coronary artery bypass grafting for coronary artery disease: Role of anesthesiologist in preoperative assessment and intraoperative management.

OBJECTIVE(S): This study aimed to determine the prevalence of carotid artery stenosis (CAS) due to atherosclerosis in neurologically asymptomatic patients undergoing coronary artery bypass grafting (CABG) for coronary artery disease (CAD). It contemplated a greater role for the cardiac anesthesiologist in the perioperative management of such patients with either previously undiagnosed carotid artery disease or towards re-assessment of severity of CAS. DESIGN: Prospective, observational clinical study. SETTING: Operation room of a cardiac surgery centre of a tertiary teaching hospital. PARTICIPANTS: A hundred adult patients with New York Heart Association (NYHA) classification I to III presenting electively for CABG. INTERVENTIONS: All patients included in this study were subjected to ultrasonic examination by means of acarotid doppler scan to access for presence of CAS just prior to induction of general anesthesia. MEASUREMENTS AND MAIN RESULTS: Based on parameters measured using carotid doppler, the presence of CAS was defined using standard criteria. The prevalence of CAS was found to be as high as 38% amongst the patients included in our study. The risk factors for CAS were identified to be advanced age, history of smoking, diabetes mellitus, dyslipidaemia and presence of a carotid bruit. CONCLUSION: This study points towards the relatively wide prevalence of carotid artery disease in neurologically asymptomatic patients undergoing CABG for CAD in the elective setting. It highlights the need to routinely incorporate carotid ultrasonography in the armamentarium of the cardiac anesthesiologist as standard of care for all patients presenting for CABG.

Comparison of the effects of inhalational anesthesia with desflurane and total intravenous anesthesia on cardiac biomarkers after aortic valve replacement.

OBJECTIVE (S): The aim of this study was to compare the effects of using inhalational anesthesia with desflurane with that of a total intravenous (iv) anesthetic technique using midazolam-fentanyl-propofol on the release of cardiac biomarkers after aortic valve replacement (AVR) for aortic stenosis (AS). The specific objectives included (a) determination of the levels of ischemia-modified albumin (IMA) and cardiac troponin I (cTnI) as markers of myocardial injury, (b) effect on mortality, morbidity, duration of mechanical ventilation, length of Intensive Care Unit (ICU) and hospital stay, incidence of arrhythmias, pacing, cardioversion, urine output, and serum creatinine. Methodology and Design: Prospective randomized clinical study. SETTING: Operation room of a cardiac surgery center of a tertiary teaching hospital. PARTICIPANTS: Seventy-six patients in New York Heart Association classification II to III presenting electively for AVR for severe symptomatic AS. INTERVENTIONS: Patients included in the study were randomized into two groups and subjected to either a desflurane-fentanyl based technique or total IV anesthesia (TIVA). Blood samples were drawn at preordained intervals to determine the levels of IMA, cTnI, and serum creatinine. MEASUREMENTS AND MAIN RESULTS: The IMA and cTnI levels were not found to be significantly different between both the study groups. Patients in the desflurane group were found to had significantly lower ICU and hospital stays and duration of postoperative mechanical ventilation as compared to those in the TIVA group. There was no difference found in mean heart rate, urine output, serum creatinine, incidence of arrhythmias, need for cardioversion, and 30-day mortality between both groups. The patients in the TIVA group had higher mean arterial pressures on weaning off cardiopulmonary bypass as well as postoperatively in the ICU and recorded lower inotrope usage. CONCLUSION: The result of our study remains ambiguous regarding the overall protective effect of desflurane in patients undergoing AVR although some benefit in terms of shorter duration of postoperative mechanical ventilation, ICU and hospital stays, as well as cTnI, were seen. However, no difference in overall outcome could be clearly established between patients who received desflurane and those that were managed solely with IV anesthetic technique using propofol.

Endoscopic sclerotherapy of gastric variceal bleeding with N-butyl-2-cyanoacrylate.

BACKGROUND: bleeding from gastric varices is a life-threatening complication of portal hypertension. Fundal and isolated gastric varices are at high risk for variceal bleeding. In this study, we report our experience with n-butyl-2-cyanoacrylate (BC) in patients with large gastric varices. STUDY: twenty-nine patients (15 male, 14 female) with large fundal varices (active bleed, 5; passive bleed after eradication of esophageal varices, 13; unbled fundal varices with red color sign, 11) underwent endoscopic sclerotherapy with BC. Cirrhosis was present in 13 patients; extrahepatic portal venous obstruction, in 13; and noncirrhotic portal fibrosis, in 3. N-Butyl-2-cyanoacrylate after mixing with lipiodol (1:1) was given to the initial 10 patients and was given in undiluted form to the remaining patients, followed by injection of 0.7 mL of distilled water to rinse the injection catheter. One to three injections (0.5-1 mL) were given until all gastric varices became hard. All patients were on long-term endoscopic sclerotherapy or variceal ligation programs for eradication of esophageal varices. RESULTS: acute variceal bleeding was controlled in all five patients with BC injections. Eradication of gastric varices was achieved in 27 (93.1%) patients (20 patients in 1 session, 4 patients in 2, and 3 patients in 3-6). Rebleeding occurred in three (10.3%) patients who responded to repeat BC injections. Complications related to the procedure occurred in two (6.9%) patients. In one patient, the needle became impacted into the tissue adhesive. This patient died 5 days later because of massive upper gastrointestinal bleeding. In the other patient, there was distal embolization. CONCLUSIONS: sclerotherapy of gastric varices with BC is a safe and an effective treatment for control of bleeding and eradication. The needle should be withdrawn immediately after the BC injection to prevent its impaction into the tissue adhesive.