MRI-Linac Economics II: Rationalizing Schedules.

OBJECTIVE: Two benefits of MR-guided radiotherapy (MRgRT) are the ability to track target structures while treatment is being delivered and the ability to adapt plans daily for some lesions based on changing anatomy. These unique capacities come at two costs: increased capital for acquisition and greatly decreased workflow. An adaptive gated stereotactic body radiotherapy (MRgART) treatment routinely takes ~90 min to perform and requires the presence of both a physician and a physicist. This may significantly limit daily capacity. We previously described how "simple cases" were necessary for proton facilities to allow for debt management. In this manuscript, we seek to determine the optimal scheduling of different MRgRT plans to recoup capital costs. MATERIALS/METHODS: We assumed an MR-linac (MRL) was completely scheduled with patients over workdays of varying duration. Treatment times and reimbursement data from our facility for varying complexities of patients were extrapolated for varying numbers treated daily. We then derived the number of adaptive and non-adaptive patients required daily to optimize the schedules. HOPPS data were used to model reimbursement. RESULTS: A single MRL treating 14 non-gated, non-adaptive IMRT patients over an 8 h workday would take about 4.8 years to cover initial acquisition and installation costs. However, such patients may be more quickly and efficiently treated with a conventional linear accelerator, while MRgART cases may only be treated with an MRL. By treating four of these daily, that same MRL room would cover costs in 2.4 years. Personnel, maintenance costs, and profit further complicate any business case for treating non-adaptive patients or for extending hours. CONCLUSIONS: In our previously published paper discussing proton therapy, we noted that debt is not variable with capacity; this remains true with MRgRT. Different from protons, a clinically optimal case load of adaptive patients provides an optimal business case as well. This requires a large patient cadre to ensure continuing throughput. As improvements in MRgRT are brought to the clinic, shorter adaptive and non-adaptive treatment times will help improve the timeframe to recoup costs but will require even more appropriate patients.

Assessment of MRI-Linac Economics under the RO-APM.

The implementation of the radiation oncology alternative payment model (RO-APM) has raised concerns regarding the development of MRI-guided adaptive radiotherapy (MRgART). We sought to compare technical fee reimbursement under Fee-For-Service (FFS) to the proposed RO-APM for a typical MRI-Linac (MRL) patient load and distribution of 200 patients. In an exploratory aim, a modifier was added to the RO-APM (mRO-APM) to account for the resources necessary to provide this care. Traditional Medicare FFS reimbursement rates were compared to the diagnosis-based reimbursement in the RO-APM. Reimbursement for all selected diagnoses were lower in the RO-APM compared to FFS, with the largest differences in the adaptive treatments for lung cancer (-89%) and pancreatic cancer (-83%). The total annual reimbursement discrepancy amounted to -78%. Without implementation of adaptive replanning there was no difference in reimbursement in breast, colorectal and prostate cancer between RO-APM and mRO-APM. Accommodating online adaptive treatments in the mRO-APM would result in a reimbursement difference from the FFS model of -47% for lung cancer and -46% for pancreatic cancer, mitigating the overall annual reimbursement difference to -54%. Even with adjustment, the implementation of MRgART as a new treatment strategy is susceptible under the RO-APM.

Harnessing COVID-Driven Technical Innovations for Improved Multi-Disciplinary Cancer Care in the Post-COVID Era: The Virtual Patient Room.

Emergence of the COVID-19 crisis has catalyzed rapid paradigm shifts throughout medicine. Even after the initial wave of the virus subsides, a wholesale return to the prior status quo is not prudent. As a specialty that values the proper application of new technology, radiation oncology should strive to be at the forefront of harnessing telehealth as an important tool to further optimize patient care. We remain cognizant that telehealth cannot and should not be a comprehensive replacement for in-person patient visits because it is not a one for one replacement, dependent on the intention of the visit and patient preference. However, we envision the opportunity for the virtual patient "room" where multidisciplinary care may take place from every specialty. How we adapt is not an inevitability, but instead, an opportunity to shape the ideal image of our new normal through the choices that we make. We have made great strides toward genuine multidisciplinary patient-centered care, but the continued use of telehealth and virtual visits can bring us closer to optimally arranging the spokes of the provider team members around the central hub of the patient as we progress down the road through treatment.

Evaluation of semiempirical VMAT dose reconstruction on a patient dataset based on biplanar diode array measurements.

We report the results of a preclinical evaluation of recently introduced commercial tools for 3D patient IMRT/VMAT dose reconstruction, the Delta4 Anatomy calculation algorithm. Based on the same initial measurement, volumetric dose can be reconstructed in two ways. Three-dimensional dose on the Delta4 phantom can be obtained by renormalizing the planned dose distribution by the measurement values (D4 Interpolation). Alternatively, incident fluence can be approximated from the phantom measurement and used for volumetric dose calculation on an arbitrary (patient) dataset with a pencil beam algorithm (Delta4 PB). The primary basis for comparison was 3D dose obtained by previously validated measurement-guided planned dose perturbation method (ACPDP), based on the ArcCHECK dosimeter with 3DVH software. For five clinical VMAT plans, D4 Interpolation agreed well with ACPDP on a homogeneous cylindrical phantom according to gamma analysis with local dose-error normalization. The average agreement rates were 98.2% ± 1.3% (1 SD), (range 97.0%-100%) and 92.8% ± 3.9% (89.5%-99.2%), for the 3%/3 mm and 2%/2 mm criteria, respectively. On a similar geometric phantom, D4 PB demonstrated substantially lower agreement rates with ACPDP: 88.6% ± 6.8% (81.2%-96.1%) and 72.4% ± 8.4% (62.1%-81.1%), for 3%/3 mm and 2%/2 mm, respectively. The average agreement rates on the heterogeneous patients' CT datasets are lower yet: 81.2% ± 8.6% (70.4%-90.4%) and 64.6% ± 8.4% (56.5%-74.7%), respectively, for the same two criteria sets. For both threshold combinations, matched analysis of variance (ANOVA) multiple comparisons showed statistically significant differences in mean agreement rates (p < 0.05) for D4 Interpolation versus ACPDP on one hand, and D4 PB versus ACPDP on either cylindrical or patient dataset on the other hand. Based on the favorable D4 Interpolation results for VMAT plans, the resolution of the reconstruction method rather than hardware design is likely to be responsible for D4 PB limitations.