Implementation of a Novel Chart Rounds Application to Facilitate Peer Review in a Virtual Academic Environment

Purpose

Peer review in the form of chart rounds is a critical component of quality assurance and safety in radiation therapy treatments. Radiation therapy departments have undergone significant changes that impose challenges to meaningful review, including institutional growth and increasing use of virtual environment. We discuss the implementation of a novel chart rounds (NCR) format and application adapted to modern peer review needs at a single high-volume multisite National Cancer Institute designated cancer center.

Methods and Materials

A working group was created to improve upon the prior institutional chart rounds format (standard chart rounds or SCR). Using a novel in-house application and format redesign, an NCR was created and implemented to accomplish stated goals. Data regarding the SCR and NCR system were then extracted for review.

Results

SCR consisted of 2- 90-minute weekly sessions held to review plans across all disease sites, review of 49 plans per hour on average. NCR uses 1-hour long sessions divided by disease site, enabling additional time to be spent per patient (11 plans per hour on average) and more robust discussion. The NCR application is able to automate a list of plans requiring peer review from the institutional treatment planning system. The novel application incorporates features that enable efficient and accurate review of plans in the virtual setting across multiple sites. A systematic scoring system is integrated into the application to record feedback. Over 5 months of use of the NCR, 1160 plans have been reviewed with 143 scored as requiring minor changes, 32 requiring major changes and 307 with comments. Major changes triggered treatment replan. Feedback from scoring is incorporated into physician workflow to ensure changes are addressed.

Conclusion

The presented NCR format and application enables standardized and highly reliable peer review of radiation therapy plans that is robust across a variety of complex planning scenarios and could be implemented globally.

Establishment of Twinning Partnership to Improve Pediatric Radiotherapy Outcomes Globally

PURPOSE

Pediatric radiotherapy is a necessary and challenging component of oncologic care for children in low- and middle-income countries (LMICs). Collaboration between institutions in LMICs and high-income countries (HICs) has been shown to be effective in improving oncologic treatment outcomes; however, literature regarding pediatric radiotherapy twinning partnerships is limited.

METHODS

Emory University has a long-standing twinning collaboration with Tikur Anbessa Specialized Hospital (TASH) for certain medical specialties. After securing institutional funding, a faculty member and a resident from the Emory University Department of Radiation Oncology set out to establish a twinning program with TASH for pediatric radiotherapy.

RESULTS

Emory and TASH faculty and residents established initial communications virtually via email and video correspondence. TASH residents and faculty completed surveys regarding pediatric radiotherapy institutional and educational needs to outline goals of collaboration. Five lectures and case-based practicums were identified focused on Wilms tumor, medulloblastoma, rhabdomyosarcoma, Hodgkin lymphoma, and palliative radiotherapy. The Emory team then conducted a visit to TASH during which lectures and practicums were delivered. The Emory team directly observed and guided simulation and treatment planning procedures. TASH residents practiced decision making, simulation, contouring, and field placement for Wilms tumor cases on the basis of didactics and feedback provided by the Emory team. Additionally, a needs assessment regarding pediatric oncologic resources was completed. Clinical care pathways and standard operating procedures were drafted by collaborators. Virtual peer-review sessions were established to continue collaborations abroad and plan for next in-person visit.

CONCLUSION

Collaborative efforts by global experts have helped to establish and improve treatment protocols for childhood cancer. The presented twinning experience may serve as a model for other LMIC and HIC centers for establishing similar partnerships.

Evaluating Pareto optimal tradeoffs for hippocampal avoidance whole brain radiotherapy with knowledge-based multicriteria optimization

The goal of this study is to investigate the Pareto optimal tradeoffs between target coverage and hippocampal sparing using knowledge-based multicriteria optimization (MCO). Ten prior clinical cases were selected that were treated with hippocampal avoidance whole brain radiotherapy (HA-WBRT) using VMAT. A new, balanced plan was generated for each case using an in-house RapidPlan model in the Eclipse V16.1 treatment planning system. The MCO decision support tool was used to create 4 Pareto optimal plans. The Pareto optimal plans were created using PTV Dmin and hippocampus Dmax as tradeoff criteria. The tradeoff plans were generated for each patient by adjusting PTV Dmin from the value achieved by the corresponding balanced plan in fixed intervals as follows: -4 Gy, -2 Gy, +2 Gy, and +4 Gy. All plans were normalized so that 95% of the PTV was covered by the prescription dose. A 1-way ANOVA, with Geisser-Greenhouse correction, was used for statistical analysis. When evaluating the achieved PTV Dmin and D98%, the results showed the dose to the hippocampus decreased as coverage lowered and in comparison, D98% was higher when the PTV coverage was increased. When comparing multiple tradeoffs, the p-value for PTV D98% was 0.0026, and the p-values for PTV D2%, PTV Dmin, Hippocampus Dmax, Dmin, and Dmean were all less than 0.0001, indicating that the tradeoff plans achieved statistically significant differences. The results also showed that Pareto optimal plans failed to reduce hippocampal dose beyond a certain point, indicating more limited achievability of the MCO-navigated plans than the interface suggested. This study presents valuable data for planning results for HA-WBRT using MCO. MCO has shown to be mostly effective in adjusting the tradeoff between PTV coverage and hippocampal dose.

Evaluating the plan quality of a general head-and-neck knowledge-based planning model versus separate unilateral/bilateral models

The implementation of knowledge-based planning (KBP) continues to grow in radiotherapy clinics. KBP guides radiation treatment design by generating clinically acceptable plans in a timely and resource-efficient manner. The role of multiple KBP models tailored for variations within a disease site remains undefined in part because of the substantial effort and number of training cases required to create a high-quality KBP model. In this study, our aim was to explore whether site-specific KBP models lead to clinically meaningful differences in plan quality for head-and-neck (HN) patients when compared to a general model. One KBP model was created from prior volumetric-modulated arc therapy (VMAT) cases that treated unilateral HN lymph nodes while another model was created from VMAT cases that treated bilateral HN nodes. Thirty cases from each model (60 cases total) were randomly selected to create a third, general model. These models were applied to 60 HN test cases - 30 unilateral and 30 bilateral - to generate 180 VMAT plans in Eclipse. Clinically relevant dose metrics were compared between models. Paired-sample t-tests were used for statistical analysis, with the threshold for statistical significance set a priori at 0.007, taking into consideration multiple hypothesis testing to avoid type I error. For unilateral test cases, the unilateral model-generated plans had significantly lower spinal cord maximum doses (12.1 Gy vs 19.3 Gy, p < 0.001) and oral cavity mean doses (20.8 Gy vs 23.0 Gy, p < 0.001), compared with the bilateral model-generated plans. The unilateral and general models generated comparable plans for unilateral HN test cases. For bilateral test cases, the bilateral model created plans had significantly lower brainstem maximum doses (10.8 Gy vs 12.2 Gy, p < 0.001) and parotid mean doses (24.0 Gy vs 25.5 Gy, p < 0.001) when compared to the unilateral model. Right parotid mean doses were lower for bilateral model plans compared to general model plans (23.8 Gy vs 24.4 Gy). The general model created plans with significantly lower brainstem maximum doses (10.3 Gy vs 10.8 Gy) and oral cavity mean doses (35.3 Gy vs 36.7 Gy) when compared with bilateral model-generated plans. The general model outperformed the bilateral model in several dose metrics but they were not deemed clinically significant. For both case sets, the unilateral and general model created plans had higher monitor units when compared to the bilateral model, likely due to more stringent constraint settings. All other dose metrics were comparable. This study demonstrates that a balanced general HN model created using carefully curated treatment plans can produce high quality plans comparable to dedicated unilateral and bilateral models.

Implementation of a Knowledge-Based Treatment Planning Model for Cardiac-Sparing Lung Radiation Therapy

PURPOSE

High radiation doses to the heart have been correlated with poor overall survival in patients receiving radiation therapy for stage III non-small cell lung cancer (NSCLC). We built a knowledge-based planning (KBP) tool to limit the dose to the heart during creation of volumetric modulated arc therapy (VMAT) treatment plans for patients being treated to 60 Gy in 30 fractions for stage III NSCLC.

METHODS AND MATERIALS

A previous study at our institution retrospectively delineated intracardiac volumes and optimized VMAT treatment plans to reduce dose to these substructures and to the whole heart. Two RapidPlan (RP) KBP models were built from this cohort, 1 model using the clinical plans and a separate model using the cardiac-optimized plans. Using target volumes and 6 organs at risk (OARs), models were trained to generate treatment plans in a semiautomated process. The cardiac-sparing KBP model was tested in the same cohort used for training, and both models were tested on an external validation cohort of 30 patients.

RESULTS

Both RP models produced clinically acceptable plans in terms of target coverage, dose uniformity, and dose to OARs. Compared with the previously created cardiac-optimized plans, cardiac-sparing RPs showed significant reductions in the mean dose to the esophagus and lungs while performing similarly or better in all evaluated heart dose metrics. When comparing the 2 models, the cardiac-sparing RP showed reduced (P < .05) heart mean and maximum doses as well as volumes receiving 60 Gy, 50 Gy, and 30 Gy.

CONCLUSIONS

By using a set of cardiac-optimized treatment plans for training, the proposed KBP model provided a means to reduce the dose to the heart and its substructures without the need to explicitly delineate cardiac substructures. This tool may offer reduced planning time and improved plan quality and might be used to improve patient outcomes.

Phaeochromocytoma presenting as Takotsubo cardiomyopathy

We report a case of a 72-year-old woman who presented with ST-elevation myocardial infarction (STEMI). However, coronary angiography showed unobstructed arteries while echocardiography (ECHO) showed severe left ventricular (LV) apical hypokinesia with ejection fraction (EF) of 25-30%. Seven months later she presented with a transient ischaemic attack and a repeat ECHO showed a normal EF.A few months later, she was diagnosed with breast cancer and as part of staging procedure, an incidental left adrenal mass was identified. This was biochemically confirmed as phaeochromocytoma (PY) and she underwent laparoscopic adrenalectomy.PY is a rare catecholamine secreting tumour arising from adrenomedullary chromaffin cells. Excessive catecholamine-induced stimulation can present as transient, reversible cardiomyopathy similar to Takotsubo cardiomyopathy and cerebrovascular events. The diagnosis of PY is often delayed but it is important to recognize PY as a cause of reversible cardiomyopathy. Early intervention is essential to improve mortality from cardiovascular and cerebrovascular complications.

MRI-based treatment planning for liver stereotactic body radiotherapy: validation of a deep learning-based synthetic CT generation method

OBJECTIVE

The purpose of this work is to develop and validate a learning-based method to derive electron density from routine anatomical MRI for potential MRI-based SBRT treatment planning.

METHODS

We proposed to integrate dense block into cycle generative adversarial network (GAN) to effectively capture the relationship between the CT and MRI for CT synthesis. A cohort of 21 patients with co-registered CT and MR pairs were used to evaluate our proposed method by the leave-one-out cross-validation. Mean absolute error, peak signal-to-noise ratio and normalized cross-correlation were used to quantify the imaging differences between the synthetic CT (sCT) and CT. The accuracy of Hounsfield unit (HU) values in sCT for dose calculation was evaluated by comparing the dose distribution in sCT-based and CT-based treatment planning. Clinically relevant dose-volume histogram metrics were then extracted from the sCT-based and CT-based plans for quantitative comparison.

RESULTS

The mean absolute error, peak signal-to-noise ratio and normalized cross-correlation of the sCT were 72.87 ± 18.16 HU, 22.65 ± 3.63 dB and 0.92 ± 0.04, respectively. No significant differences were observed in the majority of the planning target volume and organ at risk dose-volume histogram metrics ( p  >  0.05). The average pass rate of γ analysis was over 99% with 1%/1 mm acceptance criteria on the coronal plane that intersects with isocenter.

CONCLUSION

The image similarity and dosimetric agreement between sCT and original CT warrant further development of an MRI-only workflow for liver stereotactic body radiation therapy.

ADVANCES IN KNOWLEDGE

This work is the first deep-learning-based approach to generating abdominal sCT through dense-cycle-GAN. This method can successfully generate the small bony structures such as the rib bones and is able to predict the HU values for dose calculation with comparable accuracy to reference CT images.

Simulating the Effect of Spectroscopic MRI as a Metric for Radiation Therapy Planning in Patients with Glioblastoma

Due to glioblastoma's infiltrative nature, an optimal radiation therapy (RT) plan requires targeting infiltration not identified by anatomical magnetic resonance imaging (MRI). Here, high-resolution, whole-brain spectroscopic MRI (sMRI) is used to describe tumor infiltration alongside anatomical MRI and simulate the degree to which it modifies RT target planning. In 11 patients with glioblastoma, data from preRT sMRI scans were processed to give high-resolution, whole-brain metabolite maps normalized by contralateral white matter. Maps depicting choline to N-Acetylaspartate (Cho/NAA) ratios were registered to contrast-enhanced T1-weighted RT planning MRI for each patient. Volumes depicting metabolic abnormalities (1.5-, 1.75-, and 2.0-fold increases in Cho/NAA ratios) were compared with conventional target volumes and contrast-enhancing tumor at recurrence. sMRI-modified RT plans were generated to evaluate target volume coverage and organ-at-risk dose constraints. Conventional clinical target volumes and Cho/NAA abnormalities identified significantly different regions of microscopic infiltration with substantial Cho/NAA abnormalities falling outside of the conventional 60 Gy isodose line (41.1, 22.2, and 12.7 cm³, respectively). Clinical target volumes using Cho/NAA thresholds exhibited significantly higher coverage of contrast enhancement at recurrence on average (92.4%, 90.5%, and 88.6%, respectively) than conventional plans (82.5%). sMRI-based plans targeting tumor infiltration met planning objectives in all cases with no significant change in target coverage. In 2 cases, the sMRI-modified plan exhibited better coverage of contrast-enhancing tumor at recurrence than the original plan. Integration of the high-resolution, whole-brain sMRI into RT planning is feasible, resulting in RT target volumes that can effectively target tumor infiltration while adhering to conventional constraints.

Focal high-dose-rate brachytherapy: a dosimetric comparison of hemigland vs. conventional whole-gland treatment

PURPOSE

To determine the utility of focal high-dose-rate brachytherapy for localized prostate cancer, we investigated the impact on target coverage and dose to organs at risk (OARs) with hemigland (HG) compared with whole-gland (WG) treatment.

METHODS AND MATERIALS

A total of 10 WG implants were used to generate 10 WG and 20 HG (left and right) treatment plans optimized with the inverse planning simulation annealing algorithm using Oncentra MasterPlan (Nucletron B.V., Veenendaal, The Netherlands). The standard distribution of 17-18 catheters designed for WG was used to generate HG plans. The same OARs namely bladder, rectum, and urethra contours and dose constraints were applied for HG and WG plans. The HG contour was a modification of the WG contour whereby the urethra divided the prostate into HGs. The prescription dose was 7.25 Gy×6. Evaluated dose parameters were target dose D90, V100, and V150 and D0.1 cc, D1 cc, and D2 cc to OARs.

RESULTS

The HG plans had a D90, V100, and V150 to the HG target of 112%, 97.6%, and 33.8%, respectively. The WG plans had a D90, V100, and V150 to the WG target of 108%, 98.8%, and 26.5%, respectively. The OAR D2 cc doses were significantly lower in HG vs. WG plans: rectum (53.1% vs. 64.1%, p<0.0001), bladder (55.9% vs. 67.5%, p<0.0001), and urethra (69.3% vs. 95.2%, p<0.0001).

CONCLUSIONS

In the present model, HG plans yielded a statistically significant decreased radiation dose to OARs and provided complete target coverage with a catheter array designed for WG coverage. The good dosimetry results obtained in this study support the feasibility of HG brachytherapy by using a subset of the WG catheter array. Catheter distribution and dosimetry refinements tailored to subtotal prostate brachytherapy should be explored to see if further improvements in dosimetry can be achieved.

Dosimetric comparison of targeted high-dose-rate brachytherapy versus whole gland treatment

255

Background: To determine potential benefits of focal brachytherapy, we investigated target coverage and magnitude of decreased dose to organs at risk (OARs) with hemigland (HG) compared to whole gland (WG) high dose rate brachytherapy.

Methods: 10 WG implants were used to generate 10 WG and 20 HG (left and right) treatment plans using Inverse Planning Simulation Annealing in Oncentra Masterplan (Nucletron). The same distribution of 17-18 catheters was used for WG and HG plans. The same dose constraints were used for all plans (D90 100-115%, V100 97-100%, V150<35%, Rectum D0.1cc <85%, Bladder D0.1cc < 95%, and Urethra D0.1cc <110%). The HG contour was a modification of the WG contour whereby the urethra divided the prostate into hemiglands. Contours for OARs were identical. HG plans were not actually delivered. The prescription dose was 7.25 Gy x 6. A D90, V100, and V150 were calculated for HG and WG, along with D0.1cc, D1cc, D2cc, and Davg to OARs. We estimated mean difference and 95% confidence intervals for outcome measures. Bonferroni correction was used to adjust for bias due to multiple comparisons. Statistical analyses were conducted using SAS 9.2 (SAS Institute, Cary, NC), with a significance level set at p=0.003.

Results: Compared to WG, HG was associated with a higher D90 (108 vs 112%, p < 0.0001), lower V100 (98.8 vs 97.6%, p = 0.0001), and higher V150 (26.5 vs 33.8%, p = 0.0001). WG therapy resulted in higher tissue doses to OARs. Mean values for the rectum were D0.1cc (76.0 vs 71.2%, p=.0027), D1cc (68.4 vs 59.0%, p<0.0001), D2cc (64.1 vs 53.1%, p<0.0001) and Davg (27.5 vs 20.5%, p<0.0001). Mean values for the bladder were D0.1cc (83.8 vs 82.2%, p=0.0925), D1cc (73.4 vs 64.0%, p<0.0001), D2cc (67.5 vs 55.9%, p<0.0001) and Davg (22.1 vs 16.2%, p<0.0001). Mean values for the urethra were D0.1cc (106.5 vs 97.7, p<0.0001), D1cc (103.1 vs 82.9%, p<0.0001), D2cc (95.2 vs 69.3%, p<0.0001) and Davg (73.5 vs 57.2%, p<0.0001).

Conclusions: The catheter distribution used for WG may not be ideal for HG as a higher D90 and V150 was noted. HG plans decreased Davg to the rectum, bladder, and urethra by a difference of 7.0, 5.9, and 16.3%. Further research is warranted to determine whether further dose reductions can be achieved and are clinically meaningful.

Anti-inflammatory, analgesic and anti-lymphocytic activities of the aqueous extract of Crinum giganteum

The anti-inflammatory, anti-lymphocytic and analgesic properties of Crinum giganteum, a popular herb used for the management of asthma and other respiratory disorders was investigated in rats and mice. The extract dose-dependently produced significant (P<0.05) inhibition of formalin induced pain in rats. It also demonstrated significant (P<0.01) inhibition of abdominal constriction induced with 0.75% v/v acetic acid in mice. On the cotton pellet induced granulomatous tissue formation in rats, the extract significantly (P<0.05) decreased the weight. However, no significant inhibition was observed in the egg albumin-induced inflammation in rats. Oral administration of this extract in rats for 14 days significantly affected (P<0.05) the total leukocyte count and the overall percentage lymphocytes. The intraperitoneal and per oral LD(50) were 627+/-5.8mg/kg and 1486+/-18.9 mg/kg in mice and 520+/-10.2mg/kg and 1023+/-4.3 mg/kg in rats, respectively. Preliminary phytochemical analysis of the extract indicates the presence of tannins. These results therefore indicate that C. giganteum bulb contains biologically active principles, which have potentials for the treatment of inflammatory processes.