Twenty Years of Advancements in a Radiotherapy Facility: Clinical Protocols, Technology, and Management.

BACKGROUND: Hypo-fractionation can be an effective strategy to lower costs and save time, increasing patient access to advanced radiation therapy. To demonstrate this potential in practice within the context of temporal evolution, a twenty-year analysis of a representative radiation therapy facility from 2003 to 2022 was conducted. This analysis utilized comprehensive data to quantitatively evaluate the connections between advanced clinical protocols and technological improvements. The findings provide valuable insights to the management team, helping them ensure the delivery of high-quality treatments in a sustainable manner. METHODS: Several parameters related to treatment technique, patient positioning, dose prescription, fractionation, equipment technology content, machine workload and throughput, therapy times and patients access counts were extracted from departmental database and analyzed on a yearly basis by means of linear regression. RESULTS: Patients increased by 121 ± 6 new per year (NPY). Since 2010, the incidence of hypo-fractionation protocols grew thanks to increasing Linac technology. In seven years, both the average number of fractions and daily machine workload decreased by -0.84 ± 0.12 fractions/year and -1.61 ± 0.35 patients/year, respectively. The implementation of advanced dose delivery techniques, image guidance and high dose rate beams for high fraction doses, currently systematically used, has increased the complexity and reduced daily treatment throughput since 2010 from 40 to 32 patients per 8 h work shift (WS8). Thanks to hypo-fractionation, such an efficiency drop did not affect NPY, estimating 693 ± 28 NPY/WS8, regardless of the evaluation time. Each newly installed machine was shown to add 540 NPY, while absorbing 0.78 ± 0.04 WS8. The COVID-19 pandemic brought an overall reduction of 3.7% of patients and a reduction of 0.8 fractions/patient, to mitigate patient crowding in the department. CONCLUSIONS: The evolution of therapy protocols towards hypo-fractionation was supported by the use of proper technology. The characteristics of this process were quantified considering time progression and organizational aspects. This strategy optimized resources while enabling broader access to advanced radiation therapy. To truly value the benefit of hypo-fractionation, a reimbursement policy should focus on the patient rather than individual treatment fractionation.

On the evaluation of edgeless diode detectors for patient-specific QA in high-dose stereotactic radiosurgery.

PURPOSE: In this work, the potential of an innovative "edgeless" silicon diode was evaluated as a response to the still unmet need of a reliable tool for plan dosimetry verification of very high dose, non-coplanar, patient-specific radiosurgery treatments. In order to prove the effectiveness of the proposed technology, we focused on radiosurgical treatments for functional disease like tremor or pain. METHODS: The edgeless diodes response has been validated with respect to clinical practice standard detectors by reproducing the reference dosimetry data adopted for the Treatment Planning System. In order to evaluate the potential for radiosurgery patient-specific treatment plan verification, the anthropomorphic phantom Alderson RANDO has been adopted along with three edgeless sensors, one placed in the centre of the Planning Target Volume, one superiorly and one inferiorly. RESULTS: The reference dosimetry data obtained from the edgeless detectors are within 2.6% for output factor, off-axis ratio and well within 2% for tissue phantom ratio when compared to PTW 60,018 diode. The edgeless detectors measure a dose discrepancy of approximately 3.6% from the mean value calculated by the TPS. Larger discrepancies are obtained in very steep gradient dose regions when the sensors are placed outside the PTV. CONCLUSIONS: The angular independent edgeless diode is proposed as an innovative dosimeter for patient quality assurance of brain functional disorders and other radiosurgery treatments. The comparison of the diode measurements with TPS calculations confirms that edgeless diodes are suitable candidates for patient-specific dosimetric verification in very high dose ranges delivered by non-isocentric stereotactic radiosurgery modalities.

Stereotactic body radiotherapy in hepatocellular carcinoma: patient selection and predictors of outcome and toxicity.

INTRODUCTION: Stereotactic Body Radiotherapy (SBRT) emerged as a valuable option in early to advanced-stage Hepatocellular Carcinoma (HCC) as defined by Barcelona Clinic Liver Cancer (BCLC) system. The aim of our study is to evaluate SBRT in HCC patients and to identify predictors of outcome and toxicity. MATERIALS AND METHODS: A retrospective review of HCC patients treated at our Institution between November 2011 and December 2018 was carried out. SBRT was delivered in 3-10 fractions to a median Biologically Effective Dose (BED10) of 103 Gy10. RESULTS: SBRT was performed in 128 patients to 217 HCC localizations, accounting for 142 treatment courses. BCLC stage was A, B, C in, respectively, 40 (31%), 72 (56%) and 16 (13%) patients. Local Control (LC), Progression Free Survival (PFS) and Overall Survival (OS) at 2 years were, respectively: 78%, 15% and 58%. LC was influenced by BED10 > 120 Gy10 (Hazard Ratio, HR: 0.08, 95% CI 0.01-0.59; p = 0.013) and size ≥ 3 cm (HR: 2.71, 95% CI 1.10-6.66; p = 0.03). BCLC stage was correlated to PFS (median 14 vs 12 vs 5 months, p = 0.012). In BCLC stage A-B disease (n = 112), LC was associated with improved survival (median 30 months vs not reached, p = 0.036). Acute and late toxicity rate was 26% (n = 37) and 8% (n = 11). Patients with BCLC B-C stage disease showed increased acute toxicity (HR: 2.9, 95% CI 1.10-7.65; p = 0.032). CONCLUSION: Delivery of ablative doses > 120 Gy10 and tumor size are determinants of LC. Prolonged PFS and improved OS can be obtained in BCLC A-B patients. Grade 3 liver dysfunction is infrequent.

Additive Fabrication of a Vascular 3D Phantom for Stereotactic Radiosurgery of Arteriovenous Malformations.

In this study, an efficient methodology for manufacturing a realistic three-dimensional (3D) cerebrovascular phantom resembling a brain arteriovenous malformation (AVM) for applications in stereotactic radiosurgery is presented. The AVM vascular structure was 3D reconstructed from brain computed tomography (CT) data acquired from a patient. For the phantom fabrication, stereolithography was used to produce the AVM model and combined with silicone casting to mimic the brain parenchyma surrounding the vascular structure. This model was made with tissues-equivalent materials for radiology. The hollow vascular system of the phantom was filled with a contrast agent usually employed on patients for CT scans. The radiological response of the phantom was tested and compared with the one of the clinical case. The constructed model demonstrated to be a very accurate physical representation of the AVM and its vasculature and good morphological consistency was observed between the model and the patient-specific source anatomy. These results suggest that the proposed method has potential to be used to fabricate patient-specific phantoms for neurovascular radiosurgery applications and medical research.