Techniques for radioactive decontamination in nuclear medicine

Working with unsealed radioactive sources in nuclear medicine carries the potential risk of contamination. Careful design of a department and its operational procedures will minimize but never completely eliminate the possibility of such incidents occurring. Contingency planning forms as important a part of handling such incidents as the procedures to reduce the hazard once an incident has occurred. It should include anticipating where such incidents are likely to occur, training and exercising staff in the appropriate procedures to deal with these incidents, providing a comprehensive decontamination kit, and implementing a routine contamination monitoring survey. Assessing the magnitude of the radiation hazard and the effect of decontamination efforts, containing the spread of contamination, minimizing the radiation dose to individuals, and continuing to decontaminate to the lowest level possible are principles to follow in managing any incident. Nuclear medicine staff should be familiar with techniques for decontaminating different anatomical sites on the body; for eliminating or reducing the uptake of radioactivity absorbed into the body; and for decontaminating dry and wet surfaces, equipment, clothing, and bedding. Radiopharmaceutical dispensing procedures, ventilation scanning, and decontaminating 131I treatment areas are identified as the most likely causes of body surface and internal contamination of nuclear medicine staff.     

Is it safe to work with iodine-131 if you are pregnant? A risk assessment for nuclear medicine staff involved with cleaning and decontamination

In the UK, Regulation 8(5) of the Ionising Radiation Regulations 1999 (In: Work with ionising radiation. London: HSE Books, 2000) requires employers to ensure that the dose to the foetus of a pregnant worker is unlikely to exceed 1 mSv. Risk assessments are required which are capable of predicting the total foetal dose. Work involving 131I is a particular problem. Foetal dose coefficients from the maternal intake of 131I for all stages of pregnancy have been published (Phipps AW, Smith TJ, Fell TP, Harrison JD. Doses to the embryo/fetus and neonate from intake of radionuclides by the mother. NRPB contract research report 397/2001. Didcot, Oxon.: National Radiological Protection Board (NRPB), 2001. Available on website www.hse.gov.uk/research/crr_pdf/2001/crr01397.pdf), and range from 0.08 microSv x kBq(-1) at conception to 55 microSv x kBq(-1) at week 35. This paper examines one aspect of work in a nuclear medicine department in which the source of 131I is uncontrolled to determine whether the risk assessment indicates that restrictions should apply to a pregnant member of staff. Following in-patient treatment with 131I, rooms are checked and decontaminated before being decontrolled. Cleaning staff were monitored immediately after the cleaning process with hand-held detectors and by whole-body monitoring. Total body contamination ranged up to 3.2 kBq; after a change of clothing, the maximum remaining activity was 0.68 kBq. Acquired contamination correlated with the total activity administered to the patient. Hand-held monitoring rarely detected contamination. Whole-body monitoring indicated that the levels of contamination encountered could lead to a dose limit for the foetus being exceeded. These levels are very difficult to detect with hand-held monitoring. The conclusion to be drawn is that pregnant staff should be excluded from situations in which accidents could arise, or where the source of 131I is uncontrolled or unpredictable.     

Radiation protection issues of treating hyperthyroidism with 131 I in patients on haemodialysis

We report on the cases of two patients referred for 131I treatment of hyperthyroidism who were dependent on haemodialysis. Following 131I administration, all disposable lines and filters from dialysis were collected and measured for 131I radioactivity. The amount of 131I retained by the filters at the end of each successive dialysis session was found to decay with effective half-lives of 6.6+/-0.2 and 6.3+/-0.2 days. Dose rate measurements at 1m from the patients were recorded to find the effective half-life of the radioiodine clearance, which were found to be 6.9 and 7.1 days. From measured dose rates taken at 30 cm, the radiation hazard to ward staff involved in patient management was shown to be negligible.     

两例131I体内、体表污染人员的医学处理

目的 通过对2例¹³¹I体内、体表污染人员的事故经过、临床特点、剂量估算、临床救治及医学随访观察结果的报道,为类似病例的医学应急救治提供资料和经验。方法 采用全身测量装置进行放射性监测,通过INDO 2000软件进行估算剂量;医学处理包括问诊与体检、污染部位皮肤的去污洗消及综合治疗等;医学随访项目包括常规检查、肿瘤标志物检测、染色体畸变及微核分析等。结果 INDO 2000软件估算出2例事故受照人员的待积有效剂量分别为0.10~0.19Sv及0.023~0.046Sv,甲状腺的待积当量剂量分别为2.0~3.8Sv及0.46~0.89Sv。对他们进行去污洗消及综合治疗取得了较好的疗效,4年的医学随访观察未见明显异常。结论 成功地对2例¹³¹I体内、体表污染人员进行了剂量估算、医学处理及随访观察。     

Radiation dose rate and urinary activity in patients with differentiated thyroid carcinoma treated with radioiodine-131; a survey in Iranian population

The study was undertaken in order to estimate the radiation doses, that patients from Iran who received Na(131)I for the treatment of differentiated thyroid carcinoma (DTC) emit to their environment and also in order to evaluate the instructions given to these patients after being released from the nuclear medicine department. In 29 patients with DTC following thyroidectomy and immediately after the administration of therapeutic Na(131)I for the ablation of the thyroid remnants, the dose rates from the (131)I radioactivity emitted by these patients was measured at 3 meters. Also in these patients the dose rates from the (131)I were measured before they left the nuclear medicine department, at distances of 0.5 m, 1 m, and 3 m. The urine of these patients was collected for up to 3 days after (131)I administration. Results are as follows: The maximum dose received by the nursing staff was 1.6 mSv/week, less than the dose recommended by the International Committee for Radiation Protection (ICRP). The dose received by family members, as calculated on the basis of the time average dose rate on day 3 after the administration of (131)I was 46.3, 24.63, and 14.78 mSv/h at distances of 0.5, 1, and 3 m respectively. These results indicate that family members should take into consideration the duration and the distance of being in close contact with the above patients. The time-rate curve of urinary excretion of radioactivity in all patients showed multiple peaks due to the retention and redistribution of (131)I within the body and the enterohepatic cycle of radioiodinated thyroid hormones.     

Management of 131I therapy for thyroid cancer: cumulative dose from in-patients, discharge planning and personnel requirements

AIM: To provide a comprehensive overview with regard to the hospitalization/discharge planning and nursing staff requirements for the management of patients treated with radioiodine for differentiated thyroid carcinoma. METHODS: A statistical analysis of the fast clearance phase of 131I was performed in 265 hospitalized patients treated after total thyroidectomy with fixed doses ranging from 2590 to 9250 MBq. RESULTS: Two hundred and twenty-five cases were post-surgical ablation treatments and 40 cases were follow-up treatments. The 131I clearance was studied during hospitalization of 2-4 days. No clearance differences were found between the two groups. The median value of the biological half-time (T1/2bio) was 0.65 days, with a variability range of 0.30-2.03 days. A statistical model for the distribution of T(1/2bio) was reported. Some patients on maintenance haemodialysis were also studied, with T(1/2bio) values ranging from 1.6 to 2.6 days. The weekly cumulative dose to personnel from external exposure, corresponding to the 95th percentile, ranged from 0.1 mSv per GBq of administered activity (mSv x GBq(-1)) with a totally ambulant patient to 5.4 mSv . GBq with a totally helpless patient. With patients on maintenance haemodialysis, these values could increase from 1.2 to 1.7 times. The cumulative dose to close relatives was also estimated. The hospitalization times associated with 75% and 95% probabilities of patient discharge were calculated by varying the residual activity limit from 100 to 800 MBq. Finally, using the median T(1/2bio), personnel requirements were evaluated. With totally ambulant and semi-ambulant patients, about 0.5 and 1.0 personnel units per GBq of weekly administered activity were needed so as not to exceed an annual planning dose of 6 mSv per year. The treatment of patients with higher degrees of dependency was impractical. CONCLUSIONS: On the basis of statistical analysis, a better organization of in-patient treatment may be obtained, as well as more accurate preliminary evaluations of the cumulative doses to nursing staff and attending personnel, for the management of patients treated with radioiodine for differentiated thyroid carcinoma.     

A proposal to improve radioactive waste disposal following metabolic radio-iodine therapy]

After metabolic radio-iodine treatments of carcinomas of the thyroid, increased activities of I 131 are secreted from the patient's body by the renal route. The highly radioactive urine represents a serious danger of contamination for the nursing staff and third persons. The ideal conditions for the isolation of treated patients in a department disposing of a sewage disposal system of its own are not fulfilled at our hospital. Collection of radioactive urine of the patients for the purpose of annihilating radioactivity over several half-lifes of I 131 is extremely intricate. For this reason, we developed a filter system by means of which we were able to free the radioactive urine of the first five female patients treated from more than 99% of radioactivity. The contaminated locked filter patterns can be stored as "closed radio-sources" essentially more securely and space saving. The advantages of this system and their practical possibilities of use are discussed.     

Hospital discharge of patients with thyroid carcinoma treated with 131I.

A dose limit-based criterion was proposed to authorize hospital discharge of thyroid carcinoma patients treated with 131I. Evaluation of accumulated doses to determine the effective half-life, the expected accumulated dose at 1 m, and the hospitalization time was performed to ensure that the dose limit was satisfied for each patient. Situations involving different dose limits and occupancy factors were analyzed. This study dealt only with external exposure; the problem of internal contamination was not considered. METHODS: Fourteen patients treated postoperatively with 131I were studied. The range of activity was 1,110-8,175 MBq. Electronic dosimeters and thermoluminescent dosimeter chips were placed on the left pectoral muscle. Dose was measured for a mean of approximately 2.5 d. The accumulated doses were plotted as a function of time and then fitted using an exponential model to obtain the parameters of total accumulated dose and effective half-life. The doses to the public and relatives at 1 m were calculated with point source approximation and several occupancy factors. RESULTS: The fit function parameters of accumulated doses in the first 36 h predicted the behavior of the total accumulated dose within a 5% error in the parameters. Estimated values of the accumulated dose 1 m from the patient were generally <5 mSv, even for an occupancy factor of 100%. For more restrictive dose constraints, hospitalization times were calculated according to different occupancy factors, as suggested in the European Commission guide. From the fit of the measured data, values of effective half-life for each patient were obtained. CONCLUSION: To apply the dose limit-based criterion, one must calculate the patient-specific parameters, as can be done using the accumulated dose. Knowledge of patient-specific parameters ensures that the patient will not expose any individual to levels greater than the dose limit. The calculated hospitalization times were less than those recommended, especially for countries with more restrictive dose limits. The type of measurements performed in this study reveals more realistic doses for the treatment of thyroid carcinoma with 131I.     

The outcome of 131I treatment in Graves' patients pretreated or not with methimazole

Despite extensive use of iodine-131 ((131)I) treatment for Graves' hyperthyroidism, the optimal regimen of pretreatment with antithyroid drugs is still a matter of discussion. Our aim was to evaluate the success of (131)I treatment in patients with Graves' disease without and with pretreatment with methimazole (MMI). In a prospective randomized study 156 patients with Graves' disease were treated with fixed activity of 550 MBq (131)I. First group of 59 patients received only (131)I. The second group of 50 patients received MMI which was stopped seven days before (131)I. The third group of 47 patients received MMI until (131)I application. Patients were followed clinically and biochemically 1, 3, 6 and 12 months after (131)I treatment. Absorbed dose of (131)I and thyroid volume were measured in each patient. Our result showed that (131)I treatment success after twelve months was equally effective in the first and second group (96.6% and 96%, respectively), while in the third group, success was significantly lower (63.8%). Accordingly, the absorbed dose of (131)I was significantly higher in the first and in second group (144±104 Gy and 164±107 Gy, respectively), and lower in the third group (105±58 Gy). Thyroid volume gradually decreased without any significant difference between the three groups. In conclusion, our study provides evidence that application of (131)I is equally effective in the nonpretreated with MMI group and in the group discontinuing MMI one week before (131)I treatment, and it is more effective in these two groups as compared to the group in which pretreatment with MMI was administered till the day of (131)I application.     

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.     

Radioiodine-131 therapy for well-differentiated thyroid cancer--a quantitative radiation dosimetric approach: outcome and validation in 85 patients.

For almost five decades, 131I treatment of thyroid cancer has been based empirically on administered activity rather than on actual radiation doses delivered. In 1983, we defined radiation dose thresholds for successful treatment. This report is concerned with the subsequent validation of those thresholds in 85 patients. The successful ablation of thyroid remnants occurred after a single initial 131I administration in 84% of inpatients and in 79% of outpatients when treatment was standardized to a radiation dose of at least 30,000 cGy (rad). Administered activities low enough to permit outpatient therapy could be used in 47% of the patients. Lymph node metastases were treated successfully in 74% of patients with a single administration of 131I calculated to deliver at least 8,500 cGy (rad). For athyrotic patients with nodal metastases only, success was achieved in 86% of patients at tumor doses of at least 14,000 cGy (rad). These success rates are equal to or better than those reported with empiric methods of 131I administration. The individualized treatment planning selectively allocates hospitalization and higher exposures to 131I to those patients who require them.     

核医学场所空气中131I浓度监测及工作人员内照射剂量评价探讨

目的 了解医疗机构¹³¹I治疗工作场所空气中¹³¹I核素的活度浓度水平，探讨通过空气采样方法估算工作人员内照射剂量的方法并分析其影响因素。方法 选取郑州市10家开展¹³¹I核素治疗的工作场所，采用空气采样方法采集¹³¹I治疗工作场所中放射性气溶胶，用高纯锗γ能谱仪进行γ放射性核素测定并推算工作场所空气中¹³¹I核素的活度浓度水平，根据测量结果和现场调查结果估算放射工作人员因¹³¹I核素吸入导致的内照射剂量。结果 19个分装间空气样品的¹³¹I活度浓度为0.087~570 Bq/m³，平均为（51.04±128.58）Bq/m³；11个病房空气样品的¹³¹I活度浓度为0.162~54.6 Bq/m³，平均为（7.97±15.89）Bq/m³。根据GBZ 129-2016《职业性内照射个人监测规范》推荐的典型工作时间估算，放射工作人员由于吸入¹³¹I核素导致的年待积有效剂量范围为2 μSv~10 mSv，平均为（0.61±1.80）mSv，年有效剂量均未超过国家标准所规定的剂量限值。结论 郑州市10家医疗机构核医学工作场所中¹³¹I核素活度浓度较高的样品多分布在甲状腺癌住院患者较多、核素操作量较大的三甲医院，由此导致的工作人员内照射剂量不容忽视。根据空气样品的测量结果估算内照射剂量带有很大不确定度，但空气采样方法可及时发现异常或事故情况下的放射性污染，为工作人员开展体外直接测量和内照射评价提供预警。     

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。     

Unexpected dose to the daughter of a patient treated with iodine-131 for hyperthyroidism

Patients treated with radioiodine for thyrotoxicosis and hyperthyroidism are a source of radiation exposure and represent a potential radiation hazard for the people in their environment. Doses to the relatives can be estimated from dose rates of the patient or measured with a proper dosimeter. Sensitive thermoluminescent dosimeters have been used to measure the doses absorbed by the family members of patients treated with iodine-131 ((131)I) for thyrotoxicosis. In the present case, a 12 year old daughter of a female patient, aged 41 years, treated with 592 MBq of (131)I, received a dose of 7.79 mSv during the first seven days. This value is well above the dose constraints proposed by the International Commission on Radiological Protection, i.e 1 mSv for children and fetuses and 3 mSv for carers. Obviously, the patient and her daughter didn't follow the given restrictions. That was unexpected for a 12 year old child who didn't need special care and was able to understand and follow certain instructions. It is the opinion of the authors that if there are children in the family of a hyperthyroid patient treated with (131)I, they should stay in another house for at least a week. If this is impossible for social reasons, hospitalization of the patient should be considered, although treatment of thyrotoxicosis is held in an out-patient basis.     

基层医院分化型甲状腺癌131I规范化诊疗的临床体会

目的 分析安庆地区分化型甲状腺癌（DTC）的131I规范化治疗过程及现状,评价DTC在基层医院的治疗效果。 方法 收集2015年7月至2018年7月中国人民解放军海军安庆医院收治的219例DTC患者[男性48例、女性171例,年龄22~68（44.6±5.4）岁],观察131I治疗（所有患者行131I治疗前均停服左旋甲状腺素3~4周,无碘饮食,经过检查排除131I治疗禁忌后给予DTC个体化剂量口服131I治疗）后不同病理类型和是否出现转移的患者临床治疗效果,以及在治疗过程中存在的一些不规范现象;同时根据“皖西南地区核医学规范化治疗与诊断”学习班发放问卷调查表调查基层医院核医学科建设和规范化治疗开展现状,以及基层医师对DTC规范化治疗知识的掌握程度;结合门诊随访患者甲状腺球蛋白（Tg）的水平,以及甲状腺功能、甲状腺摄碘率、影像学检查的结果进行总结分析。 结果 219例DTC患者131I治疗后的平均有效率为98.6%（216/219）。在治疗过程中出现了57例患者不规范治疗现象,其中38例患者经二次手术再行131I治疗,7例转移患者经放疗或放疗后再行手术+131I治疗,8例患者“清甲”后颈部发现淋巴结转移,2例患者因促甲状腺激素（TSH）抑制不到位出现转移,2例患者（外院）未行Tg及 甲状腺球蛋白抗体的定期监测而发生转移。DTC规范化诊疗知识调查结果显示,安庆地区成立核医学的医院有2家,可以开展核素治疗的只有1家。在基层医院的医务人员中能掌握 DTC的规范化治疗知识者仅有30%（62/128） 。 随访患者Tg水平阴性187例、阳性32例,患者TSH水平控制均较理想。门诊患者甲状腺摄碘率检查结果均<1%,影像学检查结果多数为阴性。 结论 131I规范化治疗效果明显,虽然在治疗过程中还存在着一些不规范现象,但通过严格执行治疗制度,加强规范化诊疗意识,可以避免或减少不规范治疗现象的出现。     

Spurious thyroid cancer metastasis: saliva contamination artifact in high dose iodine-131 metastases survey

The use of high dose 131I for workup of thyroid cancer patients increases the chance of contamination artifact which may mimic metastases. Two elderly male patients with follicular carcinoma of the thyroid had salivary contamination artifacts on metastatic survey scans. These patients received a 1 and 10 mCi dose of 131I, respectively. The artifacts were recognized only retrospectively when follow-up scans were obtained and compared. The characteristics of contamination artifacts and several methods to confirm these are discussed.     

Radiation dose to the testes after 131I therapy for ablation of postsurgical thyroid remnants in patients with differentiated thyroid cancer.

Radioiodine-131 is used in differentiated thyroid cancer (DTC) for ablation of postsurgical thyroid remnants and destruction of metastases. The question may be raised of whether 131I treatment of DTC in male patients may give an irradiation dose to the testes that could impair fertility. Few data in the literature concern the dose absorbed by the testes after 1311 therapy for DTC. Because 131I kinetics may be altered by the hypothyroid condition commonly present at the time of treatment and by the radioiodinated iodoproteins released by the damaged thyroid tissue, the dose values reported in the International Commission on Radiological Protection (ICRP) tables for euthyroid men may not be appropriate. To clarify this problem, three male subjects undergoing 131I therapy for ablation of thyroid remnants shortly after thyroidectomy for DTC were studied. METHODS: The mean administered activity was 1256 MBq, and the duration of the study was 2 wk. The gamma dose was measured by thermoluminescent dosimeters (TLDs) applied to the lower poles of the testes. Correction factors were calculated for the distance of the TLD from the center of the testes and for attenuation by the testes of the gamma rays reaching the TLD. After correction, the gamma dose to the testes ranged from 21 to 29 mGy. The gamma dose calculated by the Medical Internal Radiation Dose (MIRD) method from blood and urine samples was similar (18-20 mGy) to that measured by TLDs. The beta dose was estimated by the MIRD method from blood activity and testicular volume and ranged between 14 and 31 mGy. Results: The total (beta and gamma) doses to testes were 30, 33 and 43 microGy/MBq in the three subjects. CONCLUSION: These values are close to those derived from the ICRP tables (26-37 microGy/MBq 131I) for euthyroid subjects. The present data indicate that significant irradiation is delivered to the testes after the administration of the 131I ablative dose to thyroidectomized patients. The relevance of the radiation absorbed by testes on fertility remains to be established.     

Dosimetry of radioiodine therapy in patients with nodular goiter after pretreatment with a single, low dose of recombinant human thyroid-stimulating hormone.

A single, low dose of recombinant human thyroid-stimulating hormone (rhTSH) doubles 24-h RAIU and causes a more homogeneous distribution of radioiodine on thyroid scintigrams of patients with nodular goiter. Pretreatment with rhTSH allows the therapeutic dose of (131)I to be reduced by 50%-60% without compromising the result of thyroid volume reduction. The present study focused on the dosimetric aspects of therapy with a reduced dose of (131)I after pretreatment with rhTSH in patients with nodular goiter. METHODS: Thirty-six patients were treated with (131)I to reduce thyroid volume. Nine patients were pretreated with a single dose of 0.01 mg of rhTSH, and 9 patients, with 0.03 mg of rhTSH. Two control groups of 9 patients, matched for thyroid weight and 24-h radioactive iodide uptake, were not pretreated with rhTSH. The therapeutic dose of (131)I was aimed at being sufficient to result in retention of 3.7 MBq of (131)I per gram of thyroid tissue at 24 h. Thyroid radioactivity after (131)I administration was measured every 24 h for 3 d and on days 7, 10, 14, 21, and 28. A model of iodine biokinetics was used to estimate absorbed doses in organs. Protein-bound (131)I activity was measured at 1, 2, 3, 7, and 10 d and at 2, 3, and 4 wk after (131)I therapy. RESULTS: The administered activities were 1.5 times lower in the 0.01-mg rhTSH group and 1.9 times lower in the 0.03-mg rhTSH group than in the control groups. The absorbed dose in the thyroid was similar in the rhTSH-pretreated groups and in the control groups. In the organs of excretion (bladder) and uptake (stomach) of inorganic iodide, the absorbed doses were 2- to 3-fold lower in the pretreated groups than in the control groups. The effective dose equivalent outside the thyroid was considerably lower in the rhTSH-pretreated groups than in their respective control groups (1.6-fold in the 0.01-mg rhTSH group and 2.3-fold in the 0.03-mg rhTSH group). The time course of protein-bound (131)I activity in serum and the cumulated protein-bound (131)I activity in serum did not differ significantly between rhTSH-pretreated and control groups. CONCLUSION: (131)I therapy after pretreatment with a single, low dose of rhTSH, with the dose reduced according to the rhTSH-induced increase in 24-h radioactive iodide uptake, caused lower radiation-absorbed doses in extrathyroidal organs and tissues, especially bladder and stomach, and no significant increase in the release of (131)I-labeled thyroid hormones into the circulation of patients with nodular goiter. Thus, this mode of therapy can be recommended, especially when the dose of radioiodine to be administered without rhTSH pretreatment is high.     

RETRACTED ARTICLE: Radiation Sialadenitis Induced by High-dose Radioactive Iodine Therapy

Radioactive iodine (¹³¹I) is accumulated in the thyroid tissue and plays an important role in the treatment of differentiated papillary and follicular cancers after thyroidectomy. Simultaneously, ¹³¹I is concentrated in the salivary glands and secreted into the saliva. Dose-related damage to the salivary parenchyma results from the ¹³¹I irradiation. Salivary gland swelling and pain, usually involving the parotid, can be seen. The symptoms may develop immediately after a therapeutic dose of ¹³¹I and/or months later and progress in intensity with time. In conjunction with the radiation sialadenitis, secondary complications reported include xerostomia, taste alterations, infection, increases in caries, facial nerve involvement, candidiasis, and neoplasia. Prevention of ¹³¹I sialadenitis may involve the use of sialogogic agents to hasten the transit time of the radioactive iodine through the salivary glands. However, studies are not available to delineate the efficacy of this approach. Treatment of the varied complications that may develop encompass numerous approaches and include gland massage, sialogogic agents, duct probing, antibiotics, mouthwashes, good oral hygiene, and adequate hydration. Recently interventional sialoendoscopy has been introduced an effective tool for the management of patients with ¹³¹I-induced sialadenitis that is unresponsive to medical treatment.     

High thyroid radiation dose associated with 131-I-19-iodocholesterol adrenal scanning.

We have examined two patients undergoing 131I-19-iodocholesterol adrenal scans in order to assess thyroidal radiation dose. Thyroid uptakes of 3--5% of the administered 2 mCi dose were found despite prior administration of Lugol's iodine. Analysis of serum samples over a ten day period after iodocholesterol injection indicated that less than 10% of the radioactivity was free iodide. Kinetic results showed a high value for the thyroid/plasma 131I ratio indicating thyroid retention of 131I. This was substantiated by thyroid scintigrams. The thyroid radiation dose was estimated to be 200--250 rad for the two patients. The associated carcinogenic risk is of sufficient magnitude, in our opinion, to warrant regular follow-up of all patients who have undergone 131I-19-iodocholesterol adrenal scanning.