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Objective To analyze the effects of target volume optimization on oral mucosal reaction and salivary gland function in oropharyngeal cancer patients receiving intensity-modulated radiotherapy(IMRT).Methods A total of 120 patients with oropharyngeal cancer admitted to Affiliated Hospital of Jiangsu University from April 2020 to August 2022 were selected and randomly grouped into control group(n=60,conventional IMRT)and treatment group(n=60,cervical region Ⅱ and the oral target region were optimized during IMRT).The therapeutic efficacy,parotid gland dose,incidence of acute oral mucosal reaction,dry mouth and oral pain at 3 months after IMRT were compared between two groups.The resting-state apparent diffusion coefficient(ADC)values of parotid and submandibular glands at different time points(before radiotherapy,the 4th week of radiotherapy,the end of radiotherapy and 3 months after radiotherapy)were recorded.Results The difference in the objective reaction rate between two groups was trivial[80.00％(48/60)vs 75.00％(45/60),P>0.05].The mean dose(Dmean)and V34 of the unaffected parotid gland and the Dmean and V30 of the oral cavity in treatment group were lower than those in control group(P<0.05).The incidences of acute oral mucosal reaction,dry mouth and oral pain at 3 months after radiotherapy in treatment group were 41.67％,50.00％,and 58.33％,lower than those in control group(75.00％,78.33％,and 85.00％)(P<0.05).The resting-state ADC values of parotid and submandibular glands at the 4th week of radiotherapy,the end of radiotherapy,and 3 months after radiotherapy in both two groups were higher than those before radiotherapy(P<0.05).At the 4th week of radiotherapy,the end of radiotherapy,and 3 months after radiotherapy,the resting-state ADC values of parotid and submandibular glands in treatment group were lower than those in control group(P<0.05).Conclusion Optimizing target volume during oropharyngeal IMRT can effectively prevent the occurrence of radiation-induced mucositis,alleviate oral mucosal reaction,oral pain and dry mouth,reduce parotid gland dose,and diminish the effects of IMRT on salivary gland function in patients.

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Objective:To investigate the feasibility of individualized primary clinical target volume (CTV) delineation in intensity-modulated radiotherapy for nasopharyngeal carcinoma (NPC).Methods:Clinical data of 87 consecutive patients newly diagnosed with lateralized NPC in Jiangsu Cancer Hospital between October 2016 and February 2018 were retrospectively analyzed. Lateralized NPC is defined as tumor invasion not exceeding the contralateral wall. According to the tumor spread, the primary CTV was optimized as follows: CTV2 only covered the medial part of the contralateral pterygopalatine fossa, whereas the contralateral foramen oval was not included; on the level of parapharyngeal space, the contralateral side of CTV only covered the posterior lateral lymph nodes, whereas the contralateral internal jugular vein was not regularly covered. Failure patterns and 5-year survival [local control rate (LCR), progression-free survival (PFS) and overall survival (OS)] were evaluated by Kaplan-Meier method. Paired t-test and rank-sum test were used to analyze the dose variation in the optimized region and adverse reactions. Results:The median follow-up time was 59.5 months. The 5-year LCR, PFS, and OS were 98.9%, 86.5% and 92.1%, respectively. There was no local recurrence in the optimized area of CTV. Dosimetric comparison results showed that the doses of parotid gland, temporal lobe, cochlea and middle ear on the contralateral side were reduced by 13.45%, 9.14%, 38.83%, and 29.36%, respectively. Four cases (4.6%) developed grade 3 hearing loss, all on the ipsilateral side. The optimized scheme significantly alleviated the hearing loss on the contralateral side compared to that on the ipsilateral side ( P<0.001). Other grade 3 late adverse reactions included cranial nerve injury, subcutaneous fibrosis in the neck and visual impairment, with 1 case each. Conclusion:Individualized primary CTV for lateralized NPC is feasible and safe, with obvious dosimetric advantages and reduced adverse reaction rate, which is worthy of clinical promotion.

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Radiotherapy is a pivotal method in cancer treatment harbouring immunomodulatory effects. Radiotherapy combined with immunotherapy has been proven to yield promising preliminary results in certain types of tumors. Most studies have concentrated on the dose fractionation of radiotherapy and timing of radiotherapy and immunotherapy. With the development of related studies, attention has been gradually paid to the influence of target volume upon circulating lymphocytes and tumor microenvironment. The interaction between target volume and immunotherapy has been valued. For tumors not suitable for hypofractionated radiotherapy, such as advanced esophageal cancer, conventional fractionated radiotherapy has been adopted. The volume and planning of target volume play a pivotal role in radiotherapy combined with immunotherapy. This article illustrates the feasibility of radiotherapy combined with immunotherapy, theory and conception of optimizing target volume.

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BACKGROUND: Titration of the continuous distending pressure during a staircase incremental-decremental pressure lung volume optimization maneuver in children on high-frequency oscillatory ventilation is traditionally driven by oxygenation and hemodynamic responses, although validity of these metrics has not been confirmed. METHODS: Respiratory inductance plethysmography values were used construct pressure-volume loops during the lung volume optimization maneuver. The maneuver outcome was evaluated by three independent investigators and labeled positive if there was an increase in respiratory inductance plethysmography values at the end of the incremental phase. Metrics for oxygenation (SpO2, FiO2), proximal pressure amplitude, tidal volume and transcutaneous measured pCO2 (ptcCO2) obtained during the incremental phase were compared between outcome maneuvers labeled positive and negative to calculate sensitivity, specificity, and the area under the receiver operating characteristic curve. Ventilation efficacy was assessed during and after the maneuver by measuring arterial pH and PaCO2. Hemodynamic responses during and after the maneuver were quantified by analyzing heart rate, mean arterial blood pressure and arterial lactate. RESULTS: 41/54 patients (75.9%) had a positive maneuver albeit that changes in respiratory inductance plethysmography values were very heterogeneous. During the incremental phase of the maneuver, metrics for oxygenation and tidal volume showed good sensitivity (> 80%) but poor sensitivity. The sensitivity of the SpO2/FiO2 ratio increased to 92.7% one hour after the maneuver. The proximal pressure amplitude showed poor sensitivity during the maneuver, whereas tidal volume showed good sensitivity but poor specificity. PaCO2 decreased and pH increased in patients with a positive and negative maneuver outcome. No new barotrauma or hemodynamic instability (increase in age-adjusted heart rate, decrease in age-adjusted mean arterial blood pressure or lactate > 2.0 mmol/L) occurred as a result of the maneuver. CONCLUSIONS: Absence of improvements in oxygenation during a lung volume optimization maneuver did not indicate that there were no increases in lung volume quantified using respiratory inductance plethysmography. Increases in SpO2/FiO2 one hour after the maneuver may suggest ongoing lung volume recruitment. Ventilation was not impaired and there was no new barotrauma or hemodynamic instability. The heterogeneous responses in lung volume changes underscore the need for monitoring tools during high-frequency oscillatory ventilation.

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The hemodynamic monitoring landscape is rapidly evolving from pressure-based and static parameters to more blood flow-based and dynamic parameters. Consensus guidelines for cardiac surgery state that the pulmonary artery catheter is neither required nor helpful in most patients. In the meantime, critical care has been searching for the alternatives to the pulmonary artery catheter and protocols for use. Best available evidence for any protocol developed suggests the inclusion of stroke volume optimization to determine fluid responsiveness. Additional strategies to using stroke volume to optimize hemodynamics, including case studies, are discussed.

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INTRODUCTION: We retrospectively evaluated the efficacy and toxicity of gross tumor volume (GTV) mean dose optimized stereotactic body radiation therapy (SBRT) for primary and secondary lung tumors with and without robotic real-time motion compensation. MATERIALS AND METHODS: Between 2011 and 2017, 208 patients were treated with SBRT for 111 primary lung tumors and 163 lung metastases with a median GTV of 8.2 cc (0.3-174.0 cc). Monte Carlo dose optimization was performed prioritizing GTV mean dose at the potential cost of planning target volume (PTV) coverage reduction while adhering to safe normal tissue constraints. The median GTV mean biological effective dose (BED)10 was 162.0 Gy10 (34.2-253.6 Gy10) and the prescribed PTV BED10 ranged 23.6-151.2 Gy10 (median, 100.8 Gy10). Motion compensation was realized through direct tracking (44.9%), fiducial tracking (4.4%), and internal target volume (ITV) concepts with small (≤5 mm, 33.2%) or large (>5 mm, 17.5%) motion. The local control (LC), progression-free survival (PFS), overall survival (OS), and toxicity were analyzed. RESULTS: Median follow-up was 14.5 months (1-72 months). The 2-year actuarial LC, PFS, and OS rates were 93.1, 43.2, and 62.4%, and the median PFS and OS were 18.0 and 39.8 months, respectively. In univariate analysis, prior local irradiation (hazard ratio (HR) 0.18, confidence interval (CI) 0.05-0.63, p = 0.01), GTV/PTV (HR 1.01-1.02, CI 1.01-1.04, p < 0.02), and PTV prescription, mean GTV, and maximum plan BED10 (HR 0.97-0.99, CI 0.96-0.99, p < 0.01) were predictive for LC while the tracking method was not (p = 0.97). For PFS and OS, multivariate analysis showed Karnofsky Index (p < 0.01) and tumor stage (p ≤ 0.02) to be significant factors for outcome prediction. Late radiation pneumonitis or chronic rip fractures grade 1-2 were observed in 5.3% of the patients. Grade ≥3 side effects did not occur. CONCLUSION: Robotic SBRT is a safe and effective treatment for lung tumors. Reducing the PTV prescription and keeping high GTV mean doses allowed the reduction of toxicity while maintaining high local tumor control. The use of real-time motion compensation is strongly advised, however, well-performed ITV motion compensation may be used alternatively when direct tracking is not feasible.

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Post hepatectomy liver failure (PHLF) remains a significant cause of morbidity and mortality after major liver resection. Although the etiology of PHLF is multifactorial, an inadequate functional liver remnant (FLR) is felt to be the most important modifiable predictor of PHLF. Pre-operative evaluation of FLR function and volume is of paramount importance before proceeding with any major liver resection. Patients with inadequate or borderline FLR volume must be considered for volume optimization strategies such as portal vein embolization (PVE), two stage hepatectomy with portal vein ligation (PVL), Yttrium-90 radioembolization, and associating liver partition and portal vein ligation for staged hepatectomy (ALPPS). This paper provides an overview of assessing FLR volume and function, and discusses indications and outcomes of commonly used volume optimization strategies.

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BACKGROUND: We retrospectively evaluated the efficacy and toxicity of gross tumor volume (GTV) mean-dose-optimized and real-time motion-compensated robotic stereotactic body radiation therapy (SBRT) in the treatment of liver metastases. METHODS: Between March 2011 and July 2015, 52 patients were treated with SBRT for a total of 91 liver metastases (one to four metastases per patient) with a median GTV volume of 12 cc (min 1 cc, max 372 cc). The optimization of mean GTV dose was prioritized during treatment planning at the potential cost of planning target volume (PTV) coverage reduction while adhering to safe normal tissue constraints. The delivered median GTV biological effective dose (BED10) was 142.1 Gy10 (range, 60.2 Gy10 -165.3 Gy10) and the prescribed PTV BED10 ranged from 40.6 Gy10 to 112.5 Gy10 (median, 86.1 Gy10). We analyzed local control (LC), progression-free interval (PFI), overall survival (OS), and toxicity. RESULTS: Median follow-up was 17 months (range, 2-49 months). The 2-year actuarial LC, PFI, and OS rates were 82.1, 17.7, and 45.0 %, and the median PFI and OS were 9 and 23 months, respectively. In univariate analysis histology (p < 0.001), PTV prescription BED10 (HR 0.95, CI 0.91-0.98, p = 0.002) and GTV mean BED10 (HR 0.975, CI 0.954-0.996, p = 0.011) were predictive for LC. Multivariate analysis showed that only extrahepatic disease status at time of treatment was a significant factor (p = 0.033 and p = 0.009, respectively) for PFI and OS. Acute nausea or fatigue grade 1 was observed in 24.1 % of the patients and only 1 patient (1.9 %) had a side effect of grade ≥ 2. CONCLUSIONS: Robotic real-time motion-compensated SBRT is a safe and effective treatment for one to four liver metastases. Reducing the PTV prescription dose and keeping a high mean GTV dose allowed the reduction of toxicity while maintaining a high local control probability for the treated lesions.

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PURPOSE: To present a novel method allowing fast volumetric optimization of tandem and ovoid high-dose-rate treatments and to quantify its benefits. METHODS AND MATERIALS: Twenty-seven CT-based treatment plans from 6 consecutive cervical cancer patients treated with four to five intracavitary tandem and ovoid insertions were used. Initial single-step optimized plans were manually optimized, approved, and delivered plans created with a goal to cover high-risk clinical target volume (HR-CTV) with D90 >90% and minimize rectum, bladder, and sigmoid D2cc. For the two-step optimized (TSO) plan, each single-step optimized plan was replanned adding a structure created from prescription isodose line to the existent physician delineated HR-CTV, rectum, bladder, and sigmoid. New, more rigorous dose-volume histogram constraints for the critical organs at risks (OARs) were used for the optimization. HR-CTV D90 and OAR D2ccs were evaluated in both plans. RESULTS: TSO plans had consistently smaller D2ccs for all three OARs while preserving HR-CTV D90. On plans with "excellent" CTV coverage, average D90 of 96% (91-102%), sigmoid, bladder, and rectum D2cc, respectively, reduced on average by 37% (16-73%), 28% (20-47%), and 27% (15-45%). Similar reductions were obtained on plans with "good" coverage, average D90 of 93% (90-99%). For plans with "inferior" coverage, average D90 of 81%, the coverage increased to 87% with concurrent D2cc reductions of 31%, 18%, and 11% for sigmoid, bladder, and rectum, respectively. CONCLUSIONS: The TSO can be added with minimal planning time increase but with the potential of dramatic and systematic reductions in OAR D2ccs and in some cases with concurrent increase in target dose coverage. These single-fraction modifications would be magnified over the course of four to five intracavitary insertions and may have real clinical implications in terms of decreasing both acute and late toxicities.

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Radon is used as environmental tracer in a wide range of applications particularly in aquatic environments. If liquid scintillation counting (LSC) is used as detection method the radon has to be transferred from the water sample into a scintillation cocktail. Whereas the volume of the cocktail is generally given by the size of standard LSC vials (20 ml) the water sample volume is not specified. Aim of the study was an optimization of the water sample volume, i.e. its minimization without risking a significant decrease in LSC count-rate and hence in counting statistics. An equation is introduced, which allows calculating the ²²²Rn concentration that was initially present in a water sample as function of the volumes of water sample, sample flask headspace and scintillation cocktail, the applicable radon partition coefficient, and the detected count-rate value. It was shown that water sample volumes exceeding about 900 ml do not result in a significant increase in count-rate and hence counting statistics. On the other hand, sample volumes that are considerably smaller than about 500 ml lead to noticeably lower count-rates (and poorer counting statistics). Thus water sample volumes of about 500-900 ml should be chosen for LSC radon-in-water detection, if 20 ml vials are applied.

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In high dose rate (HDR) brachytherapy, the source dwell times and dwell positions are vital parameters in achieving a desirable implant dose distribution. Inverse treatment planning requires an optimal choice of these parameters to achieve the desired target coverage with the lowest achievable dose to the organs at risk (OAR). This study was designed to evaluate the optimum source step size and maximum source dwell time for prostate brachytherapy implants using an Ir-192 source. In total, one hundred inverse treatment plans were generated for the four patients included in this study. Twenty-five treatment plans were created for each patient by varying the step size and maximum source dwell time during anatomy-based, inverse-planned optimization. Other relevant treatment planning parameters were kept constant, including the dose constraints and source dwell positions. Each plan was evaluated for target coverage, urethral and rectal dose sparing, treatment time, relative target dose homogeneity, and nonuniformity ratio. The plans with 0.5 cm step size were seen to have clinically acceptable tumor coverage, minimal normal structure doses, and minimum treatment time as compared with the other step sizes. The target coverage for this step size is 87% of the prescription dose, while the urethral and maximum rectal doses were 107.3 and 68.7%, respectively. No appreciable difference in plan quality was observed with variation in maximum source dwell time. The step size plays a significant role in plan optimization for prostate implants. Our study supports use of a 0.5 cm step size for prostate implants.