Target-tracking deliveries using conventional multileaf collimators planned with 4D direct-aperture optimization

Respiratory motion-induced degradation of intensity-modulated radiotherapy can be corrected by the dynamic target-tracking motion of multileaf collimator equipment on a conventional linear accelerator. This paper presents a new system by which the motion of the tissue and the delivery equipment can be incorporated into the treatment optimization using a 4D direct-aperture optimization method. The program can optimize a static or dynamic delivery with respect to a 4D patient model. The individualized patient model consists of a series of discrete phases and describes changes in tissue: deformation, geometry, attenuation and scatter properties over the breathing cycle. A set of treatment apertures is matched to the respiratory phases of the motion model, and motion of the apertures between phases is constrained by the maximum leaf velocity. Plans with dynamic and static deliveries optimized on 4D patient models were compared to static plans optimized on a single phase. This investigation was carried out on a 4D digital motion phantom and repeated on a 4D patient model. The effect of motion of the static plan on the 4D phantom was evaluated by recalculating dose from all phases of the 4D model. The plan cost was evaluated as a combination of the rms spread in tumour dose from the prescribed dose and the volume of normal lung receiving doses above 10 Gy with relative weightings of 5 and 1 respectively. The motion was found to degrade the static plan by 30 +/- 4% with respect to the 3D cost function value. In contrast, the motion did not cause significant degradation to a treatment if the treatment was optimized on the 4D phantom and the cost was improved by 16 +/- 3% by optimizing with dynamic leaf tracking motion. All results are relative to the static single-phase plan. In the 4D patient model the observed tissue motion was considerably less and the measured benefit of 4D planning was consequently reduced. For the 4D patient the plan cost was not significantly changed by the tissue motion. Optimizing on 4D patient conferred an improvement of 7.5 +/- 0.3%, and the 4D plan with dynamic leaf motion improved the plan cost by 8.3 +/- 0.1%.     

老年胃癌患者围手术期并发症及其处理

目的 研究老年胃癌患者的临床特点,总结老年胃癌患者的年龄、术前各种合并症等对术后并发症发生的影响.方法 总结自2005年1月至2007年1月接受手术的181例胃癌患者的临床资料,其中老年患者(年龄大于65岁者)65例,回顾性分析老年胃癌患者的年龄、术前各种合并症与术后并发症发生的关系.结果 老年胃癌组术前合并症总发生率为83%,非老年胃癌组为59%;老年胃癌组中有52%存在2种或2种以上合并症,发生率最高的合并症为高血压,达40%;老年胃癌患者的根治率为86%,非老年胃癌组的根治率为93%;老年胃癌组术后并发症的发生率为37%,术前合并高血压、糖尿病、肺部疾病、低蛋白血症、贫血者术后并发症发生率较高.结论 老年胃癌患者手术治疗后的总并发症发生率和病死率与非老年胃癌患者相比无差异.     

Behavioral adjustment in children with asthma: a meta-analysis.

This study is a meta-analytic review of the behavioral adjustment of children and adolescents with asthma. Of 78 studies initially reviewed, 26 studies (encompassing 28 data sets), reflecting data on nearly 5,000 children with asthma (mean age = 8.4 years; 40% female), met criteria for inclusion. Effect size estimates were calculated across studies using standard methods. Separate effect sizes were calculated for internalizing and externalizing behavioral problems, degrees of asthma severity, and differences in control group used (i.e., sample controls or normative data). Results indicate that children with asthma have more behavioral difficulties than do healthy children, with the effect for internalizing behaviors being greater than that for externalizing behaviors (d(mn) = .73 vs .40). Increased asthma severity was associated with greater behavioral difficulties. Results did not differ by comparison group (healthy controls vs normative data). The findings suggest that patients with asthma, particularly children with severe asthma, should be considered at higher risk for behavioral difficulties that may necessitate psychosocial intervention.     

Body image issues for children and adolescents with burns

Body image is a far-reaching, multidimensional, dynamic concept. Because burn injuries threaten the integrity of both the physical and psychologic identity, body-image issues related to burn injuries appear to be a meaningful area of investigation. Little research has been done to directly assess body-image issues for children and adolescents with burns. We reviewed the general findings that body-image adaptation occurs and is influenced by gender, social support, burn severity, overall adjustment, and developmental stage. It is suggested that body-image revision, if it occurs, is largely successful, but body-image issues may not be directly related to psychosocial adjustment after a burn injury.     

Management Strategies for Pain in Breast Carcinoma Patients: Current Opinions and Future Perspectives

Breast cancer is the most frequently encountered carcinoma in women worldwide. Pain is the most distressing symptom in patients with breast carcinoma and can occur at all stages of the disease due to the cancer per se as well as due to various diagnostic and treatment modalities. A proper pain assessment helps in identification of pain syndromes and guides in formulating analgesic strategies. Primary therapies of breast carcinoma like surgery, chemotherapy, and radiotherapy for bony metastases can cause substantial pain relief. However, multimodal analgesic approaches incorporating pharmacological, interventional as well as non-conventional techniques should be employed prior to, in conjunction with, and after primary therapies of breast cancer. The prevalence of chronic neuropathic pain following breast cancer surgery may exceed 50% by current estimates, and with the increase in life expectancy of these patients, providing adequate pain relief is of paramount importance to improve their quality of life. In this review, we discuss prevailing methods of evaluation and management of pain in patients of breast carcinoma and the new techniques that may become the mainstay of pain management protocols in future.     

Patterns of Insulin Dependence in an African Diabetic Clinic

SUMMARY Analysis of the age of onset of diabetes amongst insulin-treatedpatients in a large African diabetic clinic revealed a bimodaltype of distribution, 23 per cent having an age of onset before30 years and 77 per cent with onset at 30 years of age. All66 of the young insulin-treated group (21.7±4.8 years(mean±1 SD)), and a random selection of 50 older insulin-treatedpatients (49.7±10 years), were studied. The older groupwere better controlled (HbA₁ 8.4±1.7 per cent vs. 10.8±2.6per cent, p<0.001), on lower doses of insulin (49±23vs. 71±23 u/day, p<0.001) and had higher body massindex (26.0±5.6 vs. 21.8±3.5, p<0.001). SerumC-peptide (0.24±0.15 vs. 0.07±0.10 nmol/l, p<0.0001),and C-peptide/glucose ratio (2.57±2.65 vs. 0.56+0.98nmol/mmolx 10², p<0.001) were very significantly higher inolder patients. Patients with later onset disease thus had betterpreservation of pancreatic function, higher body mass indexand better glycaemic control on lower doses of insulin. Thesefeatures suggest that older insulin-treated patients could infact be ‘Type 2’ or non-insulin dependent patients,and the condition may be controllable with diet and/or oralhypoglycaemic agents, at least in some.     

The Importance of Early Carotid Endarterectomy in Symptomatic Patients

INTRODUCTION

Early carotid endarterectomy (CEA) in symptomatic patients may prevent repeat cerebral events. This study investigates the relationship between waiting time for CEA and the incidence of repeat cerebral events prior to surgery in symptomatic patients.

PATIENTS AND METHODS

A prospective database of consecutive patients undergoing CEA between January 2002 and December 2006 was reviewed. Repeat event rates prior to surgery were calculated using Kaplan–Meier analysis and predictive factors identified using Cox regression analysis.

RESULTS

A total of 118 patients underwent CEA for non-disabling stroke, TIA and amaurosis fugax. Repeat cerebral events occurred in 34 of 118 (29%) patients at a median 51 days (range, 2–360 days) after the first event. The estimated risk of repeat events was 2% at 7 days and 9% at 1 month after first event (Kaplan–Meier survival analysis). Age (HR 1.059; 95% CI 1.014–1.106; P = 0.009] was identified as a predictor of repeat events. Patients underwent surgery at median 97 days (range, 7–621 days) after the first event. Eleven of 60 (18%) patients waiting ≤?97 days for surgery and 23 of 58 (40%) patients waiting >?97 days had repeat events. (P = 0.011, chi-squared test).

CONCLUSIONS

Delays in surgery should be reduced in order to minimise repeat cerebral events in patients with symptomatic carotid stenosis, particularly in the elderly population.