ABSTRACT
Purpose To investigate time efficiency, applicability, and accuracy of using a web-based, independent quality assurance (QA) platform and vendor-dependent based system check for daily linear accelerator (LINAC) QA. Methods Time needed to perform daily QA on a single (n=1) LINAC was collected for three months. Task Group report 142 (TG-142) compliant daily QA included dosimetry checks (four photon, four electron beams); imaging checks (planar kilovolt (kV) & megavolt (MV), kV cone-beam computed tomography (CBCT)); and mechanical and safety checks using SunCHECK Machine (SCM) (Sun Nuclear Inc., Melbourne, FL, USA). Additionally, Machine Performance Check (MPC) (Varian Medical Systems, Inc., Palo Alto, CA, USA) was performed for all energies. Four trained radiation therapists performed daily QA on both platforms. Data were collected to identify the time required to complete both SCM and MPC. Additionally, the two platforms were evaluated on usability and features. Output results were compared to our monthly standard to assess accuracy. Results On average, SCM took 22 minutes with a standard deviation of six minutes and MPC took 15 minutes with a standard deviation of three minutes. MPC output results were impacted due to the beam output being coupled to the beam profile changes. As a result, the two systems on average disagreed by -1.41% after three months despite being baselined at the same time point and output agreeing well initially (average difference of -0.1% across all energies). While there was overlap in the tests performed, SCM tests were more relevant to TG-142 while MPC tests were beneficial to machine service and, with a clear understanding of the limitations of the system, found suitable as a secondary backup to SCM for daily output verification. Conclusions This work demonstrates that a comprehensive TG-142 daily QA can be designed using SCM and MPC can be added as a beneficial tool and backup for output verification while still maintaining an efficient daily QA process.
ABSTRACT
INTRODUCTION: Hematuria can be a distressing and debilitating complication of urothelial carcinoma (UC) of the kidney for patients who are not candidates for surgery or ureteroscopic ablation. We retrospectively assessed the efficacy, tolerability, and safety of stereotactic body radiotherapy (SBRT) for controlling gross hematuria in this patient population. MATERIALS AND METHODS: Institutional Review Board (IRB)-approved review of the records, laboratory values, pathology, and imaging of 8 consecutive patients treated with SBRT over a 5-year period for uncontrolled gross hematuria caused by UC of the renal pelvis or calyces. RESULTS: Therapy was delivered in 3 to 5 treatments over 1 to weeks. Individual treatments lasted an average of 17.2 minutes. No patient experienced treatment-related pain, vomiting, or diarrhea. All enjoyed cessation of bleeding within a week of completing therapy. Hematuria recurred in 2 patients in 4 and 22 months. Of the patients who have not re-bled, 3 expired of metastatic disease or co-morbidities, and 3 remain alive up to 6 years posttreatment. Of patients who have survived longer than a year, creatinine has changed by -0.05 to +0.35, and estimated glomerular filtration rate has fallen by an average of 22%. No patient has required dialysis. CONCLUSIONS: SBRT appears to be an effective and well-tolerated means of palliating gross hematuria secondary to UC of the renal pelvis or calyces in patients who are unfavorable candidates for nephrectomy or ureteroscopic ablation. Treatment was associated with a moderate decline in renal function.
