RESUMO
Purpose/Objectives: ZAP-X, a novel and dedicated radiosurgery (SRS) system, has recently emerged, while CyberKnife has solidified its position as a versatile solution for SRS and stereotactic body radiation therapy over the past two decades. This study aims to compare the dosimetric performance and delivery efficiency of ZAP-X and CyberKnife in treating brain metastases of varying target sizes, employing circular collimation. Methods and materials: Twenty-three patients, encompassing a total of 47 brain metastases, were included in the creation of comparative plans of ZAP-X and CyberKnife for analysis. The comparative plans were generated to achieve identical prescription doses for the targets, while adhering to the same dose constraints for organs at risk (OAR). The prescription isodose percentage was optimized within the range of 97-100% for each plan to ensure effective target-volume coverage. To assess plan quality, indices such as conformity, homogeneity, and gradient (CI, HI, and GI) were computed, along with the reporting of total brain volumes receiving 12Gy and 10Gy. Estimated treatment time and monitor units (MUs) were compared between the two modalities in evaluating delivery efficiency. Results: Overall, CyberKnife achieved better CI and HI, while ZAP-X exhibited better GI and a smaller irradiated volume for the normal brain. The superiority of CyberKnife's plan conformity was more pronounced for target size less than 1 cc and greater than 10 cc. Conversely, the advantage of ZAP-X's plan dose gradient was more notable for target sizes under 10 cc. The homogeneity of ZAP-X plans, employing multiple isocenters, displayed a strong correlation with the target's shape and the planner's experience in placing isocenters. Generally, the estimated treatment time was similar between the two modalities, and the delivery efficiency was significantly impacted by the chosen collimation sizes for both modalities. Conclusion: This study demonstrates that, within the range of target sizes within the patient cohort, plans generated by ZAP-X and CyberKnife exhibit comparable plan quality and delivery efficiency. At present, with the current platform of the two modalities, CyberKnife outperforms ZAP-X in terms of conformity and homogeneity, while ZAP-X tends to produce plans with a more rapid dose falloff.
RESUMO
Introduction: Poststernotomy mediastinitis (PSM) is a critical and life-threatening complication that can arise after cardiac surgery. The aim of this study was to evaluate and compare the outcomes of negative pressure wound therapy (NPWT) and conventional methods in the management of mediastinitis following heart surgery with a focus on Asian populations. Methods: For this retrospective study, we included and evaluated a total of 34 patients who had undergone cardiac operations between January 2011 and September 2021 and developed PSM. The patients were divided into two groups, the NPWT group (n = 16, 47.1%) and the conventional treatment group (n = 18, 52.9%), and compared. Results: The two groups showed no significant differences in terms of patient characteristics, PSM wound classification based on the El Oakley classification, and wound closure methods, but there was a higher incidence of diabetes mellitus in the NPWT group. With regard to mediastinal cultures, a higher prevalence of Staphylococcus epidermidis was observed in the NPWT group. However, we found no significant differences between the two groups regarding the time interval from diagnosis to wound closure, hospitalization duration, and re-exploration rate. Notably, the NPWT group exhibited a significantly higher in-hospital mortality rate than the conventional treatment group (p = 0.024). Conclusions: Our findings suggest that the use of NPWT might not lead to improved medical outcomes for patients with PSM when compared to conventional treatment methods. As a result, it becomes imperative to exercise great care when choosing patients for NPWT. To obtain more definitive and conclusive results and identify the most appropriate cases for NPWT, conducting larger randomized clinical trials is necessary.
RESUMO
PURPOSE: To monitor the radiation dose delivered and dose homogeneity to the skin and adjacent tissues around a MammoSite applicator. METHODS AND MATERIALS: Radiation surface dose was measured on 67 consecutive patients with Stage T1-T2N0M0 breast cancer implanted with the MammoSite balloon. Thermoluminescent dosimeters and metal oxide semiconductor field effect transistors were used to measure surface dose directly over the balloon, contralateral breast, thyroid, axilla, and inframammary fold. The dose homogeneity was retrospectively studied from the treatment plans in 25 patients. RESULTS: The mean maximum skin dose was 267 cGy, with a range of 56-488 cGy per fraction, 4 cGy (+/-2 cGy) to the contralateral breast, 8 cGy (+/-4 cGy) to the thyroid, 47 cGy to the ipsilateral axilla (+/-33 cGy), and 52 cGy (+/-47 cGy) to the ipsilateral inframmammary fold. The mean dose gradients were 127%, 110%, 99%, 96%, and 89% for inflated volumes of 35, 40, 50, 60, and 70 mL, respectively. CONCLUSIONS: All patients completed therapy with no or minimal skin reaction with radiation doses comparable to or better to external beam radiation. Considering the dose homogeneity, the larger inflated volume allows for better homogeneity of dose distribution, minimizes the volume of contiguous tissue that receives relatively high doses, and may reduce the risk of fat necrosis.
