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Background: A purpose of the study was to investigate the dosimetric impact of contrast media on dose calculation using average 4D contrast-enhanced computed tomography (4D-CECT) and delayed 4D-CT (d4D-CT) images caused by CT simulation contrast agents for stereotactic body radiation therapy (SBRT) of liver cases. Materials and methods: Fifteen patients of liver SBRT treated using the volumetric modulated arc therapy (VMAT) technique were selected retrospectively. 4D-CECT, and d4D-CT were acquired with the Anzai gating system and GE CT. For all patients, gross target volume (GTV) was contoured on the ten phases after rigid registration of both the contrast and delayed scans and merged to generate internal target volume (ITV) on average CT images. Region of interest (ROI) was drawn on contrast images and then copied to the delayed images after rigid registration of two average CT datasets. The treatment plans were generated for contrast enhanced average CT, delayed average CT and contrast enhanced average CT with electron density of the heart overridden. Results: No significant dosimetric difference was observed in plans parameters (mean HU value of the liver, total monitor units, total control points, degree of modulation and average segment area) except mean HU value of the aorta amongst the three arms. All the OARs were evaluated and resulted in statistically insignificant variation (p > 0.05) using one way ANOVA analysis. Conclusions: Contrast enhanced 4D-CT is advantageous in accurate delineation of tumors and assessing accurate ITV. The treatment plans generated on average 4D-CECT and average d4D-CT have a clinically insignificant effect on dosimetric parameters. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to evaluate the outcome of stereotactic body radiation therapy (SBRT) in patients of unresectable hepatocellular carcinoma (HCC) complicated with portal vein tumor thrombosis (PVTT) who are also unsuitable for other locoregional therapies. Materials and methods: Between May 2018 and January 2020, twenty-nine patients with advanced unresectable HCC s, treated with SBRT, were enrolled in this retrospective audit. Patients of Child status A5-B7 and with healthy liver volume, ≥ 700 ccs were treated. Local control (LC), overall survival (OS), progression-free survival (PFS), PVTT opening rate, and effect of prognostic factors were analyzed. Results: The median tumor diameter was 8.6 cm (5-14), and the median tumor volume was 275 cc (151-1196). The median SBRT dose prescription was 48 Gy in 6 fractions (32-50 Gy in 5-6 fractions). The median follow up was eight months (1-20), 1-year local control, progression-free survival, and overall survival were 95%, 53.4%, and 60%, respectively. Overall rate of grade III toxicity was less than 5%, and the most common toxicity was lymphocytopenia. Tumors of more than 350cc had worse OS and PFS when compared to tumors < 350 cc (median OS and PFS of tumors > 350 cc was 4 months and two months, p = .01 and .003, respectively). A total of fifteen patients progressed with the disease and the median time to progression was two months [1-4]. Conclusion: SBRT is safe and provides excellent local control in advanced HCC complicated with PVTT. The out of field failure pattern and time to failure in these patients highlights the need for adjuvant systemic therapy after completion of local treatment. Our data warrant the need for multimodality trials in this patient cohort. [ABSTRACT FROM AUTHOR]

Delivering Stereotactic Body Radiotherapy (SBRT) for Hepatocellular Carcinoma (HCC) is challenging mainly for two reasons: first, motion of the liver occurs in six degrees of freedom and, second, delineation of the tumor is difficult owing to a similar density of HCC to that of the adjoining healthy liver tissue in a non-contrast CT scan. To overcome both these challenges simultaneously, we performed a feasibility study to synchronize intravenous contrast to obtain an arterial and a delayed phase 4D CT. We included seven HCC patients of planned for SBRT. 4D CT simulation was performed with synchronized intravenous contrast based on the formula T SCAN DELAY = T peak – (L 0 /Detector Coverage × Cine Duration in Seconds). This was followed by a delayed 4D CT scan. We found that, with our protocol, it is feasible to obtain a 4DCT with an arterial and a delayed phase making it comparable to a diagnostic multi-phase CT. The peak HU of the 4D scan and diagnostic CT were similar (mean peak HU 134.2 vs 143.1, p value = 0.58 N.S). Whereas in comparison with a non-contrast CT a significant rise in the peak HU was seen (mean peak 134.2 vs 61.4 p value =.00003). A synchronized contrast 4D CT simulation for HCC is safe and feasible. It results in good contrast enhancement comparable to a diagnostic 3D contrast CT scan. [ABSTRACT FROM AUTHOR]

A typical case of fetal mummification was discussed here and was successfully manage through cesarean section [ABSTRACT FROM AUTHOR]

This report documents the dystocia due to fetal anasarca in sheep and its successful management through caesarean section. [ABSTRACT FROM AUTHOR]

Introduction . This study aimed to analyze the degree of reduction in normal liver complication probability (NTCP) from free-breathing (FB) to breath-hold (BH) liver SBRT. The effect of the radiation dose-volume on the mean liver dose (MLD) was also analyzed due to dose prescription, normal liver volume (NLV), and PTV. Materials and Methods . Thirty-three stereotactic body radiation therapy (SBRT) cases of hepatocellular carcinoma were selected, retrospectively. For FB, the treatments were planned on average intensity projection scan (CT avg ), and patient-specific internal target volume (ITV) margins were applied. To simulate the BH treatment, computed tomography (CT) scan correspond to the 40%-50% of the respiratory cycle (CT 40%-50% ) was chosen, and an appropriate intrafraction margin of 2 mm, 1.5 mm, and 1.5 mm were given in craniocaudal (CC), superior-inferior (SI), and lateral direction to generate the final iGTV. As per RTOG 1112, all organs at risk (OAR's) were considered during the optimization of treatment plans. NTCP was calculated using LKB fractionated model. Multivariate regression analysis was performed to see the effect of EQD 2Gy , NLV, and PTV on MLD 2Gy . Results. A significant dosimetric difference was observed in the normal liver (liver-ITV/iGTV). A reduction of 1.7% in NTCP was observed from FB to BH technique. The leverage of dose escalation is more in BH because MLD 2Gy corresponds to 5%, 10%, 20%, and 50% NTCP was 0.099 Gy, 0.41 Gy, 1.21 Gy, and 3.432 Gy more in BH as compared to FB technique. In MVRA, the major factor which was attributed to a change in MLD 2Gy is EQD 2Gy . Conclusion. From FB to BH technique, a significant reduction in NTCP was observed. The dose prescription is a major factor attributed to the change in MLD 2Gy . Advances in knowledge: If feasible, prefer BH treatment either for tumor dose escalation or for the reduction in NTCP., (© 2021 IOP Publishing Ltd.)