直线加速器小照野物理数据的测量和比较

背景与目的：对于精确的肿瘤放射治疗特别是立体定向和调强放射治疗,为了建立可靠的治疗计划系统剂量计算模型,提供准确的小照射物理数据尤其重要。本研究通过测量不同能量下小照野的物理数据,分析和比较不同方法和不同电离室之间相应的测量误差。方法：在直线加速器4、6、8MV光子线下,采用0．65、0．13、0．01cm^3的三种指形电离室,在30cm×30cm×30cm的固体水体模中测量了1cm×1cm～10cm×10cm照射野的总散射因子（total scatter factor,Scp）、准直器散射因子（collimator scatter factor,Sc）和组织最大剂量比（tissue-maximum ratio,TMR）等物理数据。对相应的测量结果进行了分析和比较。结果：照射野〉3cm×3cm时,不同电离室的Scp和Sc测量结果偏差在0．8％以内：3cm×3cm以下的照射野的测量结果差别较大（最大64％）;在4、6、8MV光子线1cm×1cm和2cm×2cm照射野的Sc测量中。0．13cm^3电离室拉长源皮距（〉150cm）比标准源皮距处（100cm）的测量结果分别大25．4％、6．9％、24．6％和1．4％、1．4％、2．2％;两种电离室0．01cm^3和0．13cm^3拉长距离测量的Sc对≥2cm×2cm照射野没有明显的偏差．对1cm×1cm照射野0．13cm^3比0．01cm^3测量值小0．2％、8．5％、3．4％。在1cm×1cm照射野的TMR测量中,0．01cm,和0．13cm^3电离室在15cm以下区域的测量偏差较大,约为4％左右。对于2cm×2cm及以上照射野TMR的测量结果偏差较小（〈1％）。〉3cm×3cm的照射野中,TMR测量的结果与百分深度剂量（percentage depth dose,PDD）转换得到的TMR数据在深度15cm之前一致性较好。15cm深度之后有明显的偏差（〉2％）。结论：测量小照射野物理数据时。由于侧向电子散射不够,需要谨慎选择测量探头。不同的测量探头对小照野物理数据的准确性可能存在较大的影响。当侧向电子平衡不能建立时,测量?     

贝母药材在中药和保健食品中使用的安全性探讨

贝母属(Fritillaria)植物属百合科(Liliaceae),包括暗紫贝母(F.unibracteata Hsiao et K.C.Hsia)、浙贝母(F.thunbergii Miq.)等13种国内外固有品种,以及约50余新种、40余新变种及变型。[1]中药用贝母为百合科贝母属多种植物的的干燥鳞茎,根据产地、药效的不同,贝母药材大致分成以下几大类:浙贝母、伊贝母、川贝母、湖北贝母、平贝母等。[2]贝母具有清热润肺、止咳化痰的良好功效,广泛运用于多种复方中成药中,如蛇胆川贝口服液及其他多种保健品。经过对于相关文献的研究与比较,笔者发现贝母属植物中的主要成分之一的贝母辛(peimisine)可…     

马兜铃酸肾病44例临床分析

从近6年收治的肾小管间质性疾病中,筛选出马兜铃酸肾病患者44例。分析马兜铃酸肾病的发病原因、临床表现、实验室检查和部分病例肾脏病理检查结果。结果发现本病病情呈隐匿性进展,病理以中-重度小管间质性肾炎为主,多见灶性或广泛的纤维化,少见炎细胞浸润。     

Comparison of the flow characteristics of irrigants with standard and Max‐i‐Probe needles

The objectives of this study were to determine the direction and pattern of flow of irrigating solutions inside simulated root canals with different irrigation needles; and to determine whether different needle designs increase the likelihood of irrigating solution passing through the apical foramen. Two types of needles were compared: a standard needle with a bevel and an open end, and a needle with a side opening and closed rounded tip. Observations of irrigant flow within the canals indicated that the side‐venting needle can be dangerous if the needle gauge is small and it reaches the full length of the canal, since this allowed irrigants to flow into the periapical area. With the standard needle, the fluid did not go beyond the tip of the needle when minimal irrigating pressure was employed. As the size of canal increased, the fluid did not extrude beyond the tip of both needles. However, if the needles bound in the canals, then the fluid was forced away from the needle tip, and the pressure applied to the syringe was directly proportional to the distance the fluid flowed away from the needle tip. Both side‐venting and standard needles can be used for irrigation safely and effectively if a dynamic irrigation technique (moving the needle up and down inside the canals while irrigating) is employed.     

Bone density testing among prostate cancer survivors treated with androgen‐deprivation therapy

BACKGROUND.

Androgen‐deprivation therapy (ADT) causes bone loss and fractures. Guidelines recommend bone density testing before and during ADT to characterize fracture risk. The authors of the current report assessed bone density testing among men who received ADT for ≥ 1 year.

METHODS.

Surveillance, Epidemiology, and End Results/Medicare data were used to identify 28,960 men aged > 65 years with local/regional prostate cancer diagnosed from 2001 to 2007 who were followed through 2009 and who received ≥ 1 year of continuous ADT. Bone density testing was documented in the 18‐month period beginning 6 months before ADT initiation. Logistic regression was used to identify the factors associated with bone density testing.

RESULTS.

Among men who received ≥ 1 year of ADT, 10.2% had a bone density assessment from 6 months before starting ADT through 1 year after. Bone density testing increased over time (14.5% of men who initiated ADT in 2007‐2008 vs 6% of men who initiated ADT in 2001‐2002; odds ratio for 2007‐2008 vs 2001‐2002, 2.29; 95% confidence interval, 1.83‐2.85). Less bone density testing was observed among men aged ≥ 85 years versus men ages 66 to 69 years (odds ratio, 0.76; 95% confidence interval, 0.65‐0.89), among black men versus white men (odds ratio, 0.72; 95% confidence interval, 0.61‐0.86), and among men in areas with lower educational attainment (P < .001). Men who visited a medical oncologist and/or a primary care provider in addition to a urologist had higher odds of testing than men who only consulted a urologist (P < .001).

CONCLUSIONS.

Few men who received ADT for prostate cancer underwent bone density testing, particularly older men, black men, and those living in areas with low educational attainment. Visiting a medical oncologist was associated with increased odds of testing. Interventions are needed to increase bone density testing among men who receive long‐term ADT. Data on bone density testing for nonmilitary populations of prostate cancer survivors in the United States who have received long‐term androgen‐deprivation therapy (ADT) have not been published. The current analysis of Surveillance, Epidemiology, and End Results/Medicare data suggests that few prostate cancer survivors who receive long‐term ADT undergo bone density testing; and several key populations, including African Americans and older men, have considerably lower rates of bone density screening. Cancer 2013. © 2012 American Cancer Society.