^131I对甲状腺细胞凋亡的影响

由于每个患特异性基因决定的个体辐射敏感性不同，使得每个接受^131I治疗的患对治疗的反应不一，因而疗效差异较大。针对不同的个体，采用不同的剂量治疗才可以提高^131I治疗的效率，降低甲状腺功能减退症的发病率。通过目前的分子生物学技术，我们已经了解到一些基因的蛋白表达产物(Fas／FasL、Bcl—2等)与细胞凋亡和射线诱导凋亡的联系，使对凋亡基因表达产物的体外监测成为可能。也许通过对这些指标的监测，可以使我们在^131I治疗过程中实现对不同的个体给予恰当的个体剂量。     

分化型甲状腺癌术后患者131I治疗的辐射剂量与防护

监测分化型甲状腺癌（DTC）患者术后131I治疗的辐射剂量并规范其辐射防护对DTC患者131I治疗后自身及周围人群的健康有重要意义.目前研究表明,131I治疗的DTC患者自身的辐射不良反应大多都能得到较有效地缓解和控制.只要能严格规范地遵守131I治疗DTC的辐射防护相关法规和建议,加强辐射剂量监测,并对患者、工作人员和患者家属进行适当的教育和指导,其对周围人群的辐射剂量都能达到和符合国际上的辐射防护规定.     

131I治疗Graves病血清sFas、TNF-α和sTNFR2水平的观察

Graves病（GD）属于器官特异性自身免疫性疾病，其引发甲状腺功能亢进（甲亢）的病因至今尚不完全清楚．发病机制与细胞凋亡被抑制和免疫功能缺陷有关。^131I是治疗GD甲亢患者有效的手段之一，利用其β射线对患者甲状腺滤泡集中照射达到治疗目的。本研究试图通过监测^131I治疗前后GD患者血循环中可溶性细胞凋亡相关蛋白（sFas）、肿瘤坏死因子-α（TNF—α）及可溶性肿瘤坏死因子受体2（sTNFR2）的含量变化，观察^131I治疗对GD患者甲状腺细胞凋亡相关指标的影响。     

131I扫描与断层显像定量分析甲状腺病灶的比较

131I治疗可提高DTC患者术后生存率[1].然而,目前131I治疗常采用固定剂量法,明确病灶的摄碘能力以及部位、数目,可为个体化131I治疗提供依据.本研究探讨131I断层显像评估病灶摄碘率的方法.     

131I治疗患者中核医学工作者的辐射防护

临床上已广泛应用^131I治疗甲状腺癌(DTC)的转移灶。但服用大剂量^131I后，患者体内的放射性核素对医务人员的影响值得关注。笔者监测了患者在服用^131I后不同时间、不同距离的剂量率，探讨核医学工作者的辐射防护，报道如下。     

分化型甲状腺癌骨转移大剂量131I治疗后出现重度骨髓抑制一例

笔者报道了一例131I治疗分化型甲状腺癌（DTC）骨转移出现重度骨髓抑制的病例,从临床诊断、骨髓造血系统变化、治疗过程是否规范等方面分析该病例特点,并通过文献复习加深了对131I诊治DTC骨转移的疗效以及骨髓造血影响的认识:131I诊治DTC骨转移的临床效果明显,但随着累积剂量的提升以及患者对131I治疗个体敏感度的不同可能会发生骨髓造血系统的白细胞或血小板一过性下降。对于广泛骨转移患者131I治疗时要高度警惕骨髓抑制的发生,要尽可能考虑累积治疗剂量的因素;尽量延长再次治疗的间隔时间;出现骨髓抑制现象时,要择期使用131I治疗。     

131Ⅰ治疗分化型甲状腺癌的不良反应

131I治疗DTC已有50余年历史,其可降低疾病的复发率及病死率,目前已成为DTC的主要治疗手段之一.然而大剂量131I对身体有辐射损伤风险,越来越多的研究集中于131I治疗后的近期和远期不良反应.尽管尚有许多问题存在争议,但随着临床循证医学证据的增加,人们关于131I治疗后的不良反应认识逐渐清晰.笔者就目前131I治疗DTC对患者各系统的不良影响进行综述.大剂量131I治疗引起的严重不良反应十分罕见,但是对各系统仍存在不同程度损害.临床医师应掌握循证医学证据,采取积极措施使治疗后不良反应发生率及严重程度降到最低.     

131I胶囊和液体在家兔及人体代谢的对比研究

目的观察131I胶囊和液体在家兔和甲亢患者甲状腺吸131I率(TUR)的异同,建立测量131I胶囊TUR的方法.方法①家兔实验.6只家兔随机分为胶囊组和液体组(均予7.4 MBq 131I).行γ显像,计算TUR.②甲亢患者131I胶囊标准源测量.104例Graves甲亢患者,131I示踪和治疗剂量均采用胶囊给药,与均采用液体给药的118例患者进行治疗前后24 h TUR比较.结果①家兔甲状腺对131I胶囊和液体的2,4,6,24 h TUR均无差异.②131I胶囊标准源测量溶解计数较胶囊直接测量高(13.8±2.8)%,t=8.97,P<0.01.③甲亢患者胶囊组示踪剂量TUR为(71.4±10.9)%,治疗剂量TUR为(68.5±14.7)%(t=1.62,P>0.05.);液体组分别为(71.3±12.3)%和(65.1±13.0)%(t=3.82,P<0.01).示踪剂量24 h TUR在80.0%以上者,2组治疗剂量平均TUR均低于示踪剂量.结论①家兔对131I胶囊各时相TUR与液体比较无差异.②131I胶囊做标准源须溶解于甲状腺模型内.③胶囊剂型可以作为131I治疗甲亢的标准方法.④示踪量TUR 80.0%以上者2组示踪剂量TUR均高于治疗量TUR,注意加大131I投予量.     

131Ⅰ治疗Graves''''病后甲状腺γ射线的体外测定和分析

目的了解Graves'病患者服用放射性131I治疗后24 h内甲状腺对131I的吸收情况.方法Graves'病患者18人,根据服用的131I剂量分为A组(小剂量组),服用131I剂量平均在162.8 MBq(4.4 mCi); B组(大剂量组),服用131I剂量平均在255.3 MBq(6.9 mCi),空腹服用131I后行1,2,4,8,12,24 h 6个时间点的甲状腺体外γ射线剂量率的测定.结果空腹服用131I后1 h γ射线剂量率快速增高,2～12 h为高峰持续期,随后缓慢下降,B组的高峰出现时间较早,曲线波动明显高于A组(P<0.001),但两组的曲线形态大致相同.结论Graves'病患者服用131I后1h是甲状腺快速吸收和浓聚期,12h后缓慢代谢和释放,不同的个体甲状腺吸收131I的过程有所差异.     

131I治疗分化型甲状腺癌术后患者体内剂量测定方法的临床应用进展

根据分化型甲状腺癌（DTC)患者术后不同危险度分层结果，部分患者可能需要进一步行131I治疗，但131I可对周围人群产生辐射，因此正确评估患者体内的辐射剂量，对辐射防护个体化及131I治疗流程的优化至关重要。DTC患者术后131I治疗期间辐射剂量的测量方法主要分为体内和体外测量两大类，体外测量包括尿液测量法和血液剂量测定法；体内测量主要包括局部测量法和全身测量法，笔者就辐射剂量相关测定方法及其临床应用进行综述。     

Comparison of Various Radiation Therapy Techniques in Breast Cancer Where Target Volume Includes Mammaria Interna Region

In breast cancer radiotherapy, the internal mammary lymphatic chain is treated in the target volume in a group of patients with high-risk criteria. Because of the variability of the anatomic region and structures in the irradiation field, there are a number of different techniques in breast radiotherapy. While irradiating the target volume, we also consider minimizing the dose to critical structures such as heart, lung, and contralateral breast tissue. In this study, we evaluated the dose distribution of different radiotherapy techniques in patients with left-sided breast cancer who had breast-conserving surgery. A three-dimensional computerized planning system (3DCPS) was used for each patient to compare wide-field, oblique photon-electron, and perpendicular photon-electron techniques in terms of dose homogeneities in the target volume; the doses received by the contralateral breast, heart, and lung; and the coverage of the internal mammary chain. Data from 3DCPS were controlled by the Rando-phantom and thermoluminescence dosimetry. Critical structures were irradiated with acceptable dose percentages in addition to the internal mammary chain with both wide-field and photon-electron techniques. We detected more frequent hot spots in the oblique photon-electron technique than in the other techniques, and this situation necessitated changing the junctions. The wide-field technique was easy to perform and exposed less radiation dose to the heart than photon-electron techniques. In conclusion, we suggest the use of the wide-field technique in breast irradiation when the internal mammary area is in the target volume.     

Real-time dosimetry in external beam radiation therapy

With growing complexity in radiotherapy treatment delivery, it has become mandatory to check each and every treatment plan before implementing clinically. This process is currently administered by an independent secondary check of all treatment parameters and as a pre-treatment quality assurance (QA) check for intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy treatment plans. Although pre-treatment IMRT QA is aimed to ensure the correct dose is delivered to the patient, it does not necessarily predict the clinically relevant patient dose errors. During radiotherapy, treatment uncertainties can affect tumor control and may increase complications to surrounding normal tissues. To combat this, image guided radiotherapy is employed to help ensure the plan conditions are mimicked on the treatment machine. However, it does not provide information on actual delivered dose to the tumor volume. Knowledge of actual dose delivered during treatment aid in confirming the prescribed dose and also to replan/reassess the treatment in situations where the planned dose is not delivered as expected by the treating physician. Major accidents in radiotherapy would have been averted if real time dosimetry is incorporated as part of the routine radiotherapy procedure. Of late real-time dosimetry is becoming popular with complex treatments in radiotherapy. Real-time dosimetry can be either in the form of point doses or planar doses or projected on to a 3D image dataset to obtain volumetric dose. They either provide entrance dose or exit dose or dose inside the natural cavities of a patient. In external beam radiotherapy, there are four different established platforms whereby the delivered dose information can be obtained: (1) Collimator; (2) Patient; (3) Couch; and (4) Electronic Portal Imaging Device. Current real-time dosimetric techniques available in radiotherapy have their own advantages and disadvantages and a combination of one or more of these methods provide vital information about the actual dose delivered to radiotherapy patients.     

Virtueller Bolus zur inversen Bestrahlungsplanung bei intensitätsmodulierter Radiotherapie des Mammakarzinoms im Rahmen der adjuvanten Therapie

BACKGROUND: Intensity modulated radiotherapy (IMRT) provides better sparing of normal tissue. We investigated the feasibility of inverse treatment planning for IMRT in adjuvant radiotherapy for breast cancer. MATERIAL AND METHODS: In addition to radiotherapy planning in conventional technique with tangential wedged 6-MV-photon beams we performed inversely planned IMRT (KonRad). In the CT scans for treatment planning we defined a 10-mm bolus of -60 HE density. The influence of this bolus on planning optimization was determined by optimization without and dose calculation with and without bolus. Dose calculation after dose optimization with bolus was performed using different bolus thickness to determine the influence of the bolus on dose calculation. The results were compared with dose distribution in conventional technique. RESULTS: Inverse optimization with a dose algorithm which considers tissue inhomogeneity results in unintended dose increase at the patient surface. With a virtual 10-mm bolus used for inverse optimization the dose increase was reduced. Thus, skin sparing was identical to conventional planning. The relative dose distribution was negligibly affected by the use of a 10-mm bolus. Difference in absolute dose was 3.4% compared to calculation without bolus. Therefore, the bolus must be removed before final dose calculation. CONCLUSION: The realization of inverse optimization for IMRT of the breast requires the use of a virtual bolus. Thereby, IMRT in accordance to the consensus recommendations of the EORTC, BCCG and EUSOMA is possible. Especially, the same target definition as in conventional technique may be used. IMRT techniques with a conventional beam arrangement of two tangential fields or multiple beam techniques can be realized.     

Radiogenic nephropathy

Patient-individual dosimetric analyses are a useful tool in external beam radiotherapy (EBR) to protect patients from side effects such as radiogenic nephropathy. At this point in time, individual dosimetry is not used as a standard in patient treated with radiolabelled antibody fragments or polypeptides. The reasons are a number of problems, which make patient dosimetry more challenging than in EBR. While in EBR, the dose is distributed evenly in the organ and the organ volume can exactly be determined, in internal radiotherapy the tracer is not evenly distributed within the organ leading to a non-uniform dose distribution. In addition, the dose rate of the most commonly used radionuclides is lower than in EBR and the range of their radiation differ, so that the radiobiological effects are differing considerably in comparison to EBR. Conclusion: More complex models have to be used for clinical kidney dosimetry in internal radiotherapy. In this paper, we give a concise overview of the reasons for accumulation of radiotracers in the kidney, the most recent developments in kidney dosimetry, and approaches to reduce the kidney uptake of radiotracers in order to avoid radiogenic nephropathy.     

Deoxyribonucleic acid damage-associated biomarkers of ionising radiation: current status and future relevance for radiology and radiotherapy

Diagnostic and therapeutic radiation technology has developed dramatically in recent years, and its use has increased significantly, bringing clinical benefit. The use of diagnostic radiology has become widespread in modern society, particularly in paediatrics where the clinical benefit needs to be balanced with the risk of leukaemia and brain cancer increasing after exposure to low doses of radiation. With improving long-term survival rates of radiotherapy patients and the ever-increasing use of diagnostic and interventional radiology procedures, concern has risen over the long-term risks and side effects from such treatments. Biomarker development in radiology and radiotherapy has progressed significantly in recent years to investigate the effects of such use and optimise treatment. Recent biomarker development has focused on improving the limitations of established techniques by the use of automation, increasing sensitivity and developing novel biomarkers capable of quicker results. The effect of low-dose exposure (0–100 mGy) used in radiology, which is increasingly linked to cancer incidences, is being investigated, as some recent research challenges the linear-no-threshold model. Radiotherapy biomarkers are focused on identifying radiosensitive patients, determining the treatment-associated risk and allowing for a tailored and more successful treatment of cancer patients. For biomarkers in any of these areas to be successfully developed, stringent criteria must be applied in techniques and analysis of data to reduce variation among reports and allow data sets to be accurately compared. Newly developed biomarkers can then be used in combination with the established techniques to better understand and quantify the individual biological response to exposures associated with radiology tests and to personalise treatment plans for patients.Research into the identification of biomarkers of radiation exposure is an emerging and developing area with multiple possible benefits for patients, doctors and the general public. A radiation biomarker is a biological entity that changes after exposure to radiation, allowing exposed individuals to be identified and, with some biomarkers, a dose to be estimated. There are different types of biomarkers, including chromosome aberrations, protein expression or gene expression. Some can measure accurately the dose received, while others can only indicate if a dose was received. Biomarkers can help clinicians manage treatment for a patient exposed accidentally to the wrong radiation dose or on purpose through radiotherapy. They may be able to predict the treatment response of a tumour and estimate the risk of acute or late effects in normal tissues. Biomarkers can also identify the dose received by the patient in a full or partial body exposure. Such information can help inform the necessary medical treatment plan for the patient, and it may also identify patients with a high likelihood of developing cancer in the future so that regular monitoring can be set up.     

Survey of tangential field planning and dose distribution in the UK: background to the introduction of the quality assurance programme for the START trial in early breast cancer

A background survey of UK breast radiotherapy techniques was performed prior to the introduction of the quality assurance programme for the Standardization of Radiotherapy (START) trial in breast cancer, a UK multicentre randomized trial of different dose fractionations for breast radiotherapy. Analysis of patient treatment plans was performed at this initial stage of the quality assurance programme to ensure eventual uniformity of treatment within the randomized trial and hence ensure reliable end results. As an integral part of this initial survey, three patient outlines of different size and shape were circulated between November 1997 and January 1998 to 56 UK radiotherapy centres. Dose distributions were produced according to the routine planning protocol of each department to provide information on treatment planning techniques. Criteria used for treatment plan production and the resultant dose distributions were analysed. The dose distributions varied between centres. Dose inhomogeneity of no more than 10% was achieved, on the central axis, for all chest wall and medium breast size plans. The number of larger breast size distributions exceeding a 10% dose gradient across the treatment volume was 54% (26). Most centres in the UK determine the breast dose distribution by planning on a two-dimensional contour taken along the central plane of the breast. Variation in the breast contour either side of this central plane is not taken into account. Care with plan optimization by selecting the most appropriate beam parameters can lead to an improvement in breast dosimetry.     

TLD linearity vs. beam energy and modality

Thermoluminescent dosimetry (TLD) is considered to be a valuable dosimetric tool in determining patient dose. Lithium fluoride doped with magnesium and titanium (TLD-100) is widely used, as it does not display widely divergent energy dependence. For many years, we have known that TLD-100 shows supralinearity to dose. In a radiotherapy clinic, there are multiple energies and modality beams. This work investigates whether individual linearity corrections must be used for each beam or whether a single correction can be applied to all beams. The response of TLD as a function of dose was measured from 25 cGy to 1000 cGy on both electrons and photons from 6 to 18 MeV. This work shows that, within our measurement uncertainty, TLD-100 exhibits supralinearity at all megavoltage energies and modalities.     

Treatment planning and delivery in neutron radiotherapy of soft tissue sarcomas

Well differentiated soft tissue sarcomas may benefit from fast neutron radiotherapy, in particular inoperable and recurrent tumors and tumors with residual disease after non-radical surgery. Treatment planning in a multidisciplinary pretherapeutic approach has to be based on tumor size and site and histopathology. Target volume definitions for potential microscopic spread and for the high risk region of local recurrence have to consider the preoperative tumor localization (imaging), the biological behavior and the extent of surgery. GI/II, T1-3 tumors after intralesional or marginal resection are indications for neutron therapy. Treatment planning and delivery has to take into account the narrow therapeutic range of fast neutrons and include individual immobilization devices, manufacturing of bolus and CT based computed dose calculations. Neutron radiotherapy techniques at the d, T generator are comparable to photon techniques except individual beam shaping, field size and portal verification. Total dose is 16 Gy neutrons in the high risk region and 12 to 13 Gy in the region of potential microscopic spread.     

Novel radiotherapy techniques for involved-field and involved-node treatment of mediastinal Hodgkin lymphoma

Purpose

Hodgkin lymphoma (HL) is a highly curable disease. Reducing late complications and second malignancies has become increasingly important. Radiotherapy target paradigms are currently changing and radiotherapy techniques are evolving rapidly.

Design

This overview reports to what extent target volume reduction in involved-node (IN) and advanced radiotherapy techniques, such as intensity-modulated radiotherapy (IMRT) and proton therapy–compared with involved-field (IF) and 3D radiotherapy (3D-RT)– can reduce high doses to organs at risk (OAR) and examines the issues that still remain open.

Results

Although no comparison of all available techniques on identical patient datasets exists, clear patterns emerge. Advanced dose-calculation algorithms (e.g., convolution-superposition/Monte Carlo) should be used in mediastinal HL. INRT consistently reduces treated volumes when compared with IFRT with the exact amount depending on the INRT definition. The number of patients that might significantly benefit from highly conformal techniques such as IMRT over 3D-RT regarding high-dose exposure to organs at risk (OAR) is smaller with INRT. The impact of larger volumes treated with low doses in advanced techniques is unclear. The type of IMRT used (static/rotational) is of minor importance. All advanced photon techniques result in similar potential benefits and disadvantages, therefore only the degree-of-modulation should be chosen based on individual treatment goals. Treatment in deep inspiration breath hold is being evaluated. Protons theoretically provide both excellent high-dose conformality and reduced integral dose.

Conclusion

Further reduction of treated volumes most effectively reduces OAR dose, most likely without disadvantages if the excellent control rates achieved currently are maintained. For both IFRT and INRT, the benefits of advanced radiotherapy techniques depend on the individual patient/target geometry. Their use should therefore be decided case by case with comparative treatment planning.