Metabolism in tooth enamel and reliability of retrospective dosimetry.

Most of the radiation centers in tooth enamel and bones are formed by the reactions COOH + gamma-->CO2- + H+, and CO2 + e- -->CO2-. These centers can be easily changed by metabolism and have a low stability in living organisms. The efficiency of CO2- radical production by irradiation is substantially different for teeth and bones in living rat, dead rat, and teeth and bone removed from rat. It is shown that the suitability of tooth enamel for retrospective dosimetry can be evaluated from the anisotropy of its EPR signals.     

Radiation caries

Two mechanisms are discussed regarding etiology and pathogenesis: the direct mechanism by radioeffect on teeth, lying in irradiation field, and the indirect mechanism by alteration of the secretion from salivary glands (hypo- and dyssalivation, xerostomia), alteration of the physiological mouth-flora (dominance of Streptococcus mutans) and deficient mouth and tooth hygiene by the patients. Clinically four types of radiogenic tooth defects are discerned: the superficial carious destruction of the necks of the teeth, the change of the tooth-colour to brown-black, an early gradual fuse of the edges and occlusal plane of teeth and generalised superficial defects. With the tumor diagnosis and before the beginning of radiotherapy a total dental examination of the whole mouth-cavity is to do. The therapeutic measures conform to the dimension of dental caries and the bone reduction in consequence of parodontopathies. On principle as many teeth as possible are restored and preserved, only all teeth, that can not be restored in fact and have an uncertain prognosis, are extracted selectively considering a most careful atraumatic surgical technique. The programme for mouth hygienics and tooth prophylaxis carrying out during and for many years after radiotherapy includes a careful and routine cleaning of teeth of films and tartar, frequent rinsing of the mouth with Bepanthene-, Subcutin- or sodium chloride-sodium bicarbonate solution, daily fluoride-dose by mean of fluorine gel or gel carrier, a thorough instruction and motivation of the patients and an after-care in short intervals, to recognize a reduction of cooperation, to diagnose complications as soon as possible and to begin a suitable therapy. Extraction of teeth after radiotherapy was contraindicated absolutely in the past because of the risk of following osteoradionecroses. Recent reports however show, that the risk of a postradiotherapeutic tooth extraction is not so high as suspected primarily, if the indication is paid attention to and the extraction is done according respected technical regulations. Special care has to be given to manufacture and fitting in artificial teeth. It has not to be done until all essential therapeutic effects are eased off, that usually occurs 1 to 1 1/2 years after the end of therapy.     

Humeral head necrosis following irradiation of breast carcinoma. A case report

Radiation-induced osteoradionecrosis of the ribs and brachial plexus lesions following irradiation of breast cancer patients are well known phenomena and have been reported several times in the literature. Damage to the shoulder joint after irradiation is uncommon. The case of a 75-year-old woman with breast cancer is described; she first developed a brachial plexopathy and then necrosis of the head of humerus after therapy with combined ortho-voltage and high-voltage radiation. The differential diagnosis and possible pathogenetic mechanisms are discussed.     

EPR dose reconstruction for bone-seeking 90Sr.

The results of the EPR dose reconstruction in calcified tissues of dog injected with 90Sr are presented. It has been established that there is no essential difference in the values of doses absorbed in tooth tissues of teeth in symmetric positions in the mouth, whereas a significant difference occurs in the values of absorbed doses in teeth in non-symmetric positions. In the case of 90Sr internal exposure the dose reconstruction in crown dentine plays an important role. It has been found that its quantity is close to the dose in diaphyseal cortical bone of the femur, dose at the endosteal bone surface and in femural fatty marrow. The fact that these values exceed doses absorbed in tooth enamel points out the predominant contribution of internal exposure. The highest absorbed doses have been observed in metaphyseal trabecular femur bones, tooth alveolar bone walls, and cortical and trabecular vertebra that can be considered as suitable candidates for biomarkers of internal 90Sr exposure for post-mortal autopsy. The satisfactory correlation has been found between the doses reconstructed in calcified dog tissues and the doses measured by EPR in alanine dosimeters fixed in (or nearby) the sites of autopsy of bones/teeth. The experiments provide support for the view that EPR retrospective dosimetry with calcified tissues for internal exposure is unique in providing useful information on the doses obtained.     

MR imaging of osteoradionecrosis of the mandibula following radiotherapy for head and neck cancers

Magnetic resonance (MR) images of 13 patients with osteoradionecrosis of the mandibula were analyzed. Abnormalities were noted in all patients and could be classified into three groups. In nine patients, MR signals were homogeneously low in intensity on both T1 weighted images (T1WI) and T2 weighted images (T2WI), suggesting fibrosis of bone marrow. These nine patients had suffered radiologically and/or clinically overt osteoradionecrosis more than ten months previously, and inflammatory symptoms had settled down by the time of MR study. Two patients showed low signal intensity on T1WI and an area of inhomogeneous high intensity in a diffuse area of low signal intensity on T2WI, suggesting acute inflammation in the irradiated fibrous bone marrow. Both patients suffered pathologic fracture due to osteoradionecrosis and showed severe inflammatory symptoms at the time MR study. In one of the two patients, these pathologic changes were confirmed in surgically excised mandibulectomy specimens. The other two patients showed homogeneous low signal intensity on T1WI and high signal intensity on T2WI, a finding that may be due to slight inflammation. However, in one of the two patients, this signal feature possibly indicated loose fibrosis with marked cellularity.     

Facial bone scintigraphy. III. Effects of radiation therapy.

The uptake of 99Tcm-DP in normal facial bones was not changed by irradiation of malignant tumors. The intensity of the pathologic uptake into regions with active parodontitis in a few patients increased during irradiation. The uptake of 99Tcm-DP in bone with neoplastic growth varied during the period of treatment, probably depending on the tumor reaction to irradiation.     

Osteoradionecrosis of the Mandibula in Patients Treated with Different Fractionations

PURPOSE: The incidence of osteonecrosis of the mandibula (ON) after irradiation using modern three-dimensional planning as well as hyperfractionation or moderately accelerated irradiation has been evaluated and compared with the incidence of the preceding period. PATIENTS AND METHODS: The records of 268 head and neck cancer patients irradiated between January 1, 1980 and December 31, 1998 with a dose to the mandibula of at least 60 Gy were retrospectively analyzed. All patients had CT-based treatment planning, computerized dose calculation with isodose charts also in several off-axis planes, and regular verification films. RESULTS: The long-term cumulative incidence of ON needing mandibular resection was as follows: after conventional fractionation 6.2% (between 60 and 66.6 Gy target dose) or 20.1% (between > 66.6 and 72 Gy); after hyperfractionated irradiation with a target dose between 72 and 78.8 Gy 6.6%; after concomitant boost irradiation according to the MDA/Houston regime with a dose between 63.9 and 70.5 Gy: no case; after 6 x 2 Gy/week or 7 x 1.8 Gy/week and a total target dose between 66 and 72 Gy approximately 17% or higher (small patient number). CONCLUSION: Comparison of the incidence of ON during the period between 1980 and 1990 with the following period between 1990 and 1998 shows a decrease in risk to a value of approximately 5% using modern three-dimensional techniques as well as hyperfractionation or moderately accelerated fractionation.     

电离辐射致股骨头坏死早期病理特点和机制的研究

目的 观察单次大剂量射线引起大鼠股骨头坏死的早期病理改变,为放射性骨坏死特别是放射性股骨头坏死的早期诊断和防治研究提供依据。方法 ¹³⁷Cs γ射线(30 Gy)体外局部单侧单次照射大鼠股骨头,受照后2、6和12周取双侧股骨头HE染色,光镜观察病理改变;照后2周骨髓间充质干质细胞(bone marrow mesenchymal stem cells ,BMSCs)分离培养,观察BMSCs增殖和集落形成能力;照后12周血管内灌注Microfill造影剂,采用微CT对股骨头毛细血管网进行三维重建和分析。结果 ¹³⁷Cs γ射线局部照射后,受照侧股骨头软骨柱紊乱,骨细胞核皱缩、数量减少、空骨陷窝增多、骨小梁面积减少(P<0.05);受照侧股骨头毛细血管密度由未照侧的12.3%降至6.65%(P<0.05); BMSCs生长缓慢,集落形成率为10%,较对照组(21%)明显下降(P<0.05)。结论 30 Gy单次局部照射后骨组织病理改变主要表现为空骨陷窝增加,照射后6周空骨陷窝率达30%可作为放射性股骨头坏死早期预诊断的指标之一。辐射致股骨头损伤甚至坏死除了射线对骨组织的损伤外,还与射线对骨髓BMSCs和毛细血管的损伤有关。     

Local and systemic effects of radiation on bone metabolism measured by quantitative SPECT.

Quantitative bone scintigraphy (QBS), which measures 99mTc-MDP uptake expressed as percent of injected dose per cc, indicates bone metabolism. It is measured in the bones of patients before and after radiation treatment and then compared to normal controls. QBS was performed in a group of 22 normal individuals and was measured twice, 2-10 mo (mean 4.9) apart. There was no significant difference between the two measurements. QBS was performed also in 28 patients before, immediately after and at certain time intervals after radiation therapy for cancer. Both the irradiated and the nonirradiated bones showed significant decreases in bone metabolism at 2-18 mo (mean 8.8) after irradiation. In addition, increases and decreases of 99mTc-MDP uptake were similar in the irradiated and in the nonirradiated bones, and there were significant correlations of the QBS values in the different bones of each individual patient. The etiology of the changes in bone metabolism in the nonirradiated bones is not yet fully understood, but it appears to be the result of a systemic effect of radiation.     

Bone cement used as an embolic agent for active bleeding in vertebroplasty of metastatic lesions

We treated two cases of bleeding by injecting bone cement into tumor-feeding vessels of metastatic hypervascular tumors during a percutaneous vertebroplasty (PV) procedure. When the inner needle was pulled out after puncture of the metastatic vertebral tumor, active arterial bleeding from the outer needle cannula was noticed. Bleeding was not stopped by injection of Gelfoam particles through the cannula. Thus, bone cement was injected, which filled the tumor-feeding vessels, and bleeding stopped. Skin rash and high fever occurred 2-3 hours after the PV procedure, probably due to allergic reaction and massive tumor necrosis. To decrease the risk of active bleeding during PV for hypervascular bone metastases, arterial embolization of the feeding arteries should be performed 1 or 2 days prior to PV. If active bleeding occurs through the outer needle when performing PV, injection of bone cement after confirmation of bleeding from the tumor feeding vessels by vertebrography is effective.     

Radiotherapy of carcinoma of the auditory canal

From 1973 through 1986, twelve patients suffering from carcinomas of the outer auditory canal were irradiated at the Radiologic Hospital of Essen. The five-year survival was 64% after postoperative irradiation and 0% after irradiation alone. Considering the data communicated by other authors, the following therapy recommendations can be deduced: early stages where bones or cartilages are not involved represent an indication for sole operation. These tumors can be successfully treated by sole radiotherapy, too. In case of greater tumors, combined surgery and postoperative radiotherapy is the most favorable method. Besides a high total dose (50 to 60 Gy for microscopic tumor residues, about 70 Gy for macroscopic tumor residues), a sufficiently great target volume has to be chosen which includes the ear, the temporal bone, the preauricular lymph nodes and the angle of mandible. To prevent bone and cartilage necroses, it is recommended to restrict the individual doses to 1.8 to 2 Gy each.     

Hyperbaric oxygen therapy in the treatment of complications of irradiation in head and neck area.

BACKGROUND AND PURPOSE: We have investigated the treatment results of hyperbaric oxygen (HBO2) to patients with radiation-induced tissue complications. MATERIAL AND METHODS: Eight patients (1.4%) from 548 with head and neck cancers treated surgically with post- or preoperative radiotherapy or radiotherapy alone in standard doses who developed postradiation complications (6 patients with laryngeal chondroradionecrosis, 1 patient with osteoradionecrosis of the temporal bone, and 1 patient with soft tissue radionecrosis) are presented. To evaluate radiation reactions occuring in the head and neck region, we used the Chandler grading system for classification of postradiation larynx injuries and SOMA/LENT score for classification of postradiation injuries of mucosa of upper aerodigestive tract. Grades I and II in those grading systems are expected side effects of radiation therapy, thus our cases were all in grades III and IV. The HBO2 was performed after failure of the conventional treatment (antibiotics, steroids, topical therapy). The number of HBO2 expositions was from 8 to 39 and the delay to therapy from 2 to 22 months. RESULTS: Symptoms resolved in all treated patients. Six patients with laryngeal chondroradionecrosis had no symptoms after therapy and in three of them after partial laryngectomy the decannulation was performed. In one patient with mucosal radionecrosis after total laryngectomy, the esophageal fistula was closed and in one patient with osteoradionecrosis of the temporal bone, wound debridement followed. CONCLUSION: The authors' experience supports the increasing clinical evidence that HBO2 is an effective adjunct therapy for treatment of complications of irradiation in head and neck area.     

Optimizing parameters for the use of alternate light sources in detecting fragmentary bones: a pilot study

ABSTRACT

Recent studies have suggested that alternate light sources (ALS) are effective in detecting bone and teeth fragments at crime scenes. These studies, however, are few in number and provide no consensus as to the optimum combination of wavelength and filter for best detecting bone from non-bone material. Additionally, each study has been conducted using different environments, bone species and varying degrees of exposure to taphonomic factors. The aim of this study was to investigate the optimum parameters of ALS for the detection of bone and teeth fragments in a laboratory setting. Human and non-human bone, and tooth fragments were compared with non-bone material using handheld Rofin Poliflares. Temperature-treated bones (frozen, boiled and burnt) were included to assess if taphonomic factors affected fluorescence. Wavelengths ranging from 415 nm–530 nm were used and fluorescence was recorded using photographic images, and intensity analysed in ImageJ. Results of this pilot study found that the 450 nm Poliflare with orange filter provided the best discrimination of bone/tooth versus non-bone when used at a distance of up to 100 cm from the objects. Fluorescence of heat-treated bones is weakened at distances greater than 30 cm, which should be taken into account when temperature modification to remains is suspected.     

介入等综合治疗激素性股骨头坏死的实验研究

目的 :探讨药物介入等综合疗法治疗激素性股骨头坏死的作用机制。方法 :将 32只兔子随机分为对照组、模型组、介入组和综合组。于介入前后行血管造影检查 ,并于治疗后 8周 ,分别进行血脂及病理学观察。结果 :介入组和综合组血管中断现象改善 ,终末小血管数目增多。介入组动物总胆固醇、甘油三脂 ,股骨头空骨陷窝率均明显低于模型组 (P<0 0 5 ) ,软骨下区血管数目增多 (P <0 0 1)。综合组与模型组比较 ,甘油三脂明显降低 ,有显著差异 (P <0 0 1) ,与介入组比较亦有差异 (P <0 0 5 ) ;总胆固醇降低 ,与模型组比较仍有差异 (P <0 0 5 ) ;空骨陷窝率较模型组显著降低 (P <0 0 1) ,软骨下区血管数目明显增多 (P <0 0 0 1)。结论 :介入和综合方法治疗股骨头缺血性坏死均有效 ,通过降低血脂 ,改善微循环 ,增加软骨下区血管数目 ,降低骨内压 ,促进坏死骨的修复和新骨再生 ,综合组疗效优于单纯介入治疗组     

Deciduous teeth development in fetuses using postmortem computed tomography image analysis

Fetal age is estimated widely by body length and weight and skeletal or dental development and maturation. Regarding dental development, dental development charts reported by Schour and Massler and Ubelaker are well known. We tried to calculate the calcification rate of the deciduous teeth, mandibular cortical bone, and clavicle in fetuses utilizing postmortem computed tomography (CT) image analysis. The CT values within the circumferential area of the region of interest were automatically calculated using a software, and the calcification rate was calculated by performing single regression analysis. Our results showed that deciduous tooth calcification could be detected in over 19-week-old fetuses using CT images. The calcification of bones (mandibular cortical bone and clavicle) started earlier than the calcification of deciduous teeth. However, the calcification rate of the bones was slower compared to that of the deciduous teeth. The calcification rate of the deciduous teeth in fetuses using CT value may be effective to estimate fetal age and evaluate deciduous teeth development, suggesting that our established method is effective for age estimation in forensic dentistry.     

牙再植150例临床分析

目的探讨影响再植牙成功的相关因素。方法对175颗再植牙的类型、治疗方法及临床疗效进行分析。结果再植牙成功率为84%;根管治疗后移植组与未进行根管治疗再植组的成功率分别为:90.4%、74.3%,两组相比,差异有统计学意义(P<0.05)。活髓牙再植后牙髓血管再生,根尖完全形成,3年后复查牙髓存活率为8.0%。结论牙髓血管再生是牙再植术成功的关键,而根管治疗是再植牙治疗的重要手段,早期根管治疗可预防或减少再植牙的牙根吸收。     

Radiographic manifestations of bone metastases from renal carcinoma.

From 1964 to 1974, 1,668 patients with renal carcinoma were seen at the Mayo Clinic. Bone metastases were present in 167 of these patients (only lung metastatic involvement ranked higher in frequency). More than one-third of the patients with bone metastasis from renal carcinoma had this as a presenting lesion of occult renal tumor. This group constituted 4% of all patients with renal carcinoma evaluated during the study period. While most bone lesions were in the pelvis and lower lumbar spine, any bone may be involved. All patients with bone metastases from renal carcinoma have a poor prognosis. However, some bone lesions appeared as long as 10 or more years after the initial tumor. The most common radiographic features are a lytic destructive process with indistinct margins, erosion of the cortex, and frequent expansion into the soft tissues. Pathological features are common in the long bones, and calcifications are occasionally seen. The synovial joints are not affected. A well defined sclerotic margin is a common finding after radiation treatment, although it is not a reliable indicator of the stability of the lesion.     

Age assessment at the time of death based on panoramic radiography

BACKGROUND: The determination of age at the time of death is an important method in forensic anthropology and paleodemography. The possible postmortem investigation of the teeth and jaws enables the determination of age at the time of death, as the bones and teeth are both resistant to degradation in soil and characterized by age-related morphological changes. The aim of this study was to determine whether the age-related changes visible on panoramic radiography correlated with age, and enabled the assessment of individual age. METHODS: Seven radiographic parameters were used in the study: tooth loss, occlusal tooth wear, pulp stones, carious teeth, periapical disease, tooth restoration, and alveolar bone loss associated with periodontal disease. RESULTS: The material comprised 314 dental panoramic tomograms of living patients of both sexes with documented age (18 to 77 years). Multiple regression equations were constructed for the age estimation, including four parameters (the number of missing teeth, the number of intact teeth, the distance of cement-enamel junction from the alveolar ridge, the number of abraded teeth). The nature of data treated by regression analysis required the careful choice of parameters, appropriate functional model for each parameter, and the experience of the investigator. With the four parameters included in equations, the error was +/- 2.55 years. CONCLUSION: This preliminary analysis showed that the conventional regression technique could be appropriate for the age estimation based on panoramic radiography, and that an additional study with a larger sample and on wider population was required.     

Osteomyelitis of the foot in diabetic patients: evaluation with plain film, 99mTc-MDP bone scintigraphy, and MR imaging

Diagnosis of osteomyelitis of the foot in diabetic patients may be difficult because of the coexistence of chronic cellulitis, vascular insufficiency, and peripheral neuropathy. This study compared the diagnostic accuracies of plain films, bone scans, and MR imaging studies in diabetic patients with suspicion of osteomyelitis of the foot. Twenty-nine plain radiographs, 20 bone scans, and 30 MR studies were obtained in 24 patients. Twenty-nine bones from 14 patients were pathologically proved either positive (25 bones) or negative (four bones) for osteomyelitis. Another 15 bones (10 patients) studied with MR had no pathologic proof, but the bones healed with only local wound care and/or a short course of oral antibiotics. These patients had trauma, cellulitis, or unhealed ulcers. The sensitivity and specificity of plain films were both 75%. Bone scans had a very low specificity (100% false-positive rate). A negative bone scan should strongly exclude the probability of osteomyelitis. Unlike the findings in previous reports, MR had much higher sensitivity and specificity than bone scans in detecting osteomyelitis in diabetic patients. When the 10 patients without pathologic proof (those who presumably had neuroarthropathy, vascular insufficiency, and/or cellulitis) were included, the sensitivity and specificity of all three techniques decreased. Our experience with this small group of patients suggests that MR is a useful imaging technique for diagnosing osteomyelitis of the foot in diabetic patients.     

Role of Interstitial PDR Brachytherapy in the Treatment of Oral and Oropharyngeal Cancer

PURPOSE: To evaluate the role of pulsed-dose-rate interstitial brachytherapy (PDR IBT) in patients with head-and-neck malignancies. PATIENTS AND METHODS: From October 1997 to December 2003, 236 patients underwent PDR IBT for head-and-neck cancer at the authors' department. 192 patients received brachytherapy as part of their curative treatment regimen after minimal non-mutilating surgery, 44 patients were treated with irradiation alone. 144 patients had sole IBT (median D(REF) = 56 Gy), in 92 patients IBT procedures (median D(REF) = 24 Gy) were performed in combination with external irradiation. The pulses (0.4-0.7 Gy/h) were delivered 24 h a day with a time interval of 1 h between two pulses. The analysis of tumor control, survival and treatment-related toxicity was performed after a median follow-up of 26 months (6-75 months). RESULTS: At the time of analysis permanent local tumor control was registered in 208 of 236 patients (88%). At 5 years overall survival and local recurrence-free survival of the entire group were 82-73% and 93-83% for T1/2, and 56% and 83% for T3/4, respectively. Soft-tissue necrosis was seen in 23/236 patients (9.7%) and bone necrosis in 17/236 patients (7.2%). No other serious side effects were observed. CONCLUSION: PDR IBT with 0.4-0.7 Gy/h and 1 h between pulses is safe and effective. These results confirm that PDR IBT of head-and-neck cancer is comparable with low-dose-rate (LDR) brachytherapy - equally effective and less toxic.