High dose proton and photon-based radiation therapy for 213 liver lesions: a multi-institutional dosimetric comparison with a clinical perspective.

BACKGROUND: Stereotactic radiotherapy (SRT) and Proton therapy (PT) are both options in the management of liver lesions. Limited clinical-dosimetric comparison are available. Moreover, dose-constraint routinely used in liver PT and SRT considers only the liver spared, while optimization strategies to limit the liver damaged are poorly reported. METHODS: Primary endpoint was to assess and compare liver sparing of four contemporary RT techniques. Secondary endpoints were freedom from local recurrence (FFLR), overall survival (OS), acute and late toxicity. We hypothesize that Focal Liver Reaction (FLR) is determined by a similar biologic dose. FLR was delineated on follow-up MRI. Mean C.I. was computed for all the schedules used. A so-called Fall-off Volume (FOV) was defined as the area of healthy liver (liver-PTV) receiving more than the isotoxic dose. Fall-off Volume Ratio (FOVR) was defined as ratio between FOV and PTV. RESULTS: 213 lesions were identified. Mean best fitting isodose (isotoxic doses) for FLR were 18Gy, 21.5 Gy and 28.5 Gy for 3, 5 and 15 fractions. Among photons, an advantage in terms of healthy liver sparing was found for Vmat FFF with 5mm jaws (p = 0.013) and Cyberknife (p = 0.03). FOV and FOVR resulted lower for PT (p < 0.001). Three years FFLR resulted 83%. Classic Radiation induced liver disease (RILD, any grade) affected 2 patients. CONCLUSIONS: Cyberknife and V-MAT FFF with 5mm jaws spare more liver than V-MAT FF with 10 mm jaws. PT spare more liver compared to photons. FOV and FOVR allows a quantitative analysis of healthy tissue sparing performance showing also the quality of plan in terms of dose fall-off.

Comparing Visual and Software-Based Quantitative Assessment Scores of Lungs' Parenchymal Involvement Quantification in COVID-19 Patients.

(1) Background: Computed tomography (CT) plays a paramount role in the characterization and follow-up of COVID-19. Several score systems have been implemented to properly assess the lung parenchyma involved in patients suffering from SARS-CoV-2 infection, such as the visual quantitative assessment score (VQAS) and software-based quantitative assessment score (SBQAS) to help in managing patients with SARS-CoV-2 infection. This study aims to investigate and compare the diagnostic accuracy of the VQAS and SBQAS with two different types of software based on artificial intelligence (AI) in patients affected by SARS-CoV-2. (2) Methods: This is a retrospective study; a total of 90 patients were enrolled with the following criteria: patients' age more than 18 years old, positive test for COVID-19 and unenhanced chest CT scan obtained between March and June 2021. The VQAS was independently assessed, and the SBQAS was performed with two different artificial intelligence-driven software programs (Icolung and CT-COPD). The Intraclass Correlation Coefficient (ICC) statistical index and Bland-Altman Plot were employed. (3) Results: The agreement scores between radiologists (R1 and R2) for the VQAS of the lung parenchyma involved in the CT images were good (ICC = 0.871). The agreement score between the two software types for the SBQAS was moderate (ICC = 0.584). The accordance between Icolung and the median of the visual evaluations (Median R1-R2) was good (ICC = 0.885). The correspondence between CT-COPD and the median of the VQAS (Median R1-R2) was moderate (ICC = 0.622). (4) Conclusions: This study showed moderate and good agreement upon the VQAS and the SBQAS; enhancing this approach as a valuable tool to manage COVID-19 patients and the combination of AI tools with physician expertise can lead to the most accurate diagnosis and treatment plans for patients.

Radioguided lung lesion localization: introducing a fluoroscopy system in a SPECT/CT scan.

PURPOSE: The purpose was to report our experience in the use of radiotracer localization and resection of small, indistinct, or nonpalpable pulmonary lesions. We developed an innovative technique implementing a fluoroscopy system on a single-photon emission computed tomography/computed tomography (SPECT/CT) scan that allowed to perform CT-guided injection of radiotracer directly on SPECT/CT. PATIENTS AND METHODS: Patients were selected for the radiotracer procedure in presence of difficulties in locating nodules with video-assisted thoracoscopic surgery (VATS). Overall, 0.2 ml of technetium-99m macroaggregated albumin and 0.3 ml of nonionic iodinated contrast were injected under CT guidance. During the VATS procedure, an endoscopic gamma detecting probe was introduced to scan the lung surface. The area of major radioactivity, which matched with the area of the nodule, was resected. RESULTS: Between January 2016 and October 2018, 37 patients underwent CT-guided radiotracer injection. The mean nodule size was 11 mm. CT nodule morphology characteristics were as follows: 15 nodules were ground glass, 12 were solid, and 10 were partly solid. No significant adverse events occurred. In one patient, the surgeons decided for an open thoracotomy after unsuccessfully VATS. Overall, lobectomy was performed in two patients, segmentectomy in one, and wedge resection in 33 patients. No mortality occurred. The pathological diagnosis was 15 (42%) primary lung cancer, eight (22%) metastases, and 13 (36%) benign lesions. CONCLUSION: Radioguided pulmonary nodule localization is a reliable procedure with a high rate of success, minimal complications, and lower risk of failures, with no associated mortality or significant morbidity. Our SPECT/CT system is the first to benefit from the technological improvement with successfully implementation and application of fluoroscopy to SPECT/CT.