Ectopic accumulation of99mTc-HMDP in primary lung cancer in comparison with CT findings

The purpose of this study was to evaluate the frequency and the extent of extraosseous^99mTc-HMDP accumulation in 412 patients with primary lung cancer. CT scanning was also performed and we compared the extraosseous uptake by lung cancer with the internal structure of the tumor on CT scans. The extent of ectopic^99mTc-HMDP accumulation was classified as low, moderate or high. CT scans were used to evaluate the size and internal structure of the tumor, including calcification and necrosis. Ectopic^99mTc-HMDP accumulation in primary lung cancer was found in 32 patients (7.7%), and included 2 cases (0.5%) of high uptake, 8 cases (1.9%) of moderate uptake, and 22 cases (5%) of low uptake. No difference in uptake was observed among the histological types, but a relationship between tumor size and^99mTc-HMDP extraosseous accumulation was observed. CT scans of the 32 tumors exhibiting ectopic^99mTc-HMDP accumulation revealed 5 cases of calcification in the tumor and 18 cases of tumor necrosis. The factors promoting ectopic^99mTc-HMDP accumulation were considered to be tumor size and calcification or necrotic change. In patients with neither calcification nor necrosis, other factors such as increased calcium metabolism and altered vascular permeability may be involved.     

Potential of (99m)Tc-MIBI for detecting bone marrow metastases.

In this study, we evaluated the potential of (99m)Tc-hexakis-2-methoxyisobutylisonitrile (MIBI) for detecting bone metastases in comparison with a conventional bone tracer. METHODS: (99m)Tc-MIBI and (99m)Tc-hydroxymethylene diphosphonate (HMDP) scans were obtained from 99 patients with proven malignant diseases and suspected bone metastases. We compared 373 lesions that showed abnormal uptake on (99m)Tc-MIBI scans or (99m)Tc-HMDP scans (or both). RESULTS: Bone metastases were confirmed in 334 of 373 lesions. Thirty-nine lesions on (99m)Tc-HMDP scans had false-positive findings, but only 2 of these lesions had false-positive findings on (99m)Tc-MIBI scans. (99m)Tc-MIBI and (99m)Tc-HMDP scans were equivalent in 168 of 334 lesions (50.3%). (99m)Tc-MIBI scans correctly detected more lesions than (99m)Tc-HMDP scans: 284 lesions (85.0%) versus 218 lesions (65.3%) (P < 0.005), respectively. (99m)Tc-MIBI scans showed a markedly higher sensitivity for detecting metastases in the femur and humerus compared with (99m)Tc-HMDP scans: 97 of 98 lesions (99.0%) versus 35 of 98 lesions (35.7%) (P < 0.005) and 21 of 22 lesions (95.5%) versus 11 of 22 lesions (50.0%) (P < 0.005), respectively. (99m)Tc-HMDP scans of 17 patients showed no abnormal images. However, (99m)Tc-MIBI scans correctly detected bone metastases, and subsequent development of multiple lesions was observed on follow-up (99m)Tc-HMDP scans of 15 patients. (99m)Tc-MIBI scans were superior to (99m)Tc-HMDP scans in the detection of metastases attributed to breast cancer, multiple myeloma, and hepatoma. On the contrary, (99m)Tc-MIBI scans were less sensitive than (99m)Tc-HMDP scans for detecting bone metastases attributed to prostate cancer in the other skeletal sites except for femur and humerus. CONCLUSION: (99m)Tc-MIBI scans have better sensitivity for detecting bone metastases and provide more specific complementary findings than conventional bone scans. (99m)Tc-MIBI accumulation attributed to bone marrow metastases may occur at an early stage, before the bone remodeling process in the surrounding bone can be detected on conventional bone scans.     

Monitoring of response to radiation therapy for human tumor xenografts using<Superscript>99m</Superscript>Tc-HL91 (4,9-diaza-3,3,10,10-tetramethyldodecan-2,11-dione dioxime)

PURPOSE: Oxygenation status of tumor tissue is an important factor to discriminate it with respect to its radiosensitivity. 99mTc-4,9-diaza-3,3,10,10-tetramethyldodecan-2,11-dione dioxime (99mTc-HL91) is retained in hypoxic tissues, making it possible to use it as hypoxic imaging agent. We evaluated if the accumulation of 99mTc-HL91 in tumors could aid in the prediction of sensitivity of radiation therapy of cancers. METHODS: Human tumors (the gastric cancer cell line: MKN45, the epidermoid carcinoma cell line: KB-31, and the lung adenocarcinoma cell line: HLC) were xenografted into the thigh of athymic mice and irradiated with a 4 MV linear accelerator. Tumor growth was measured and 99mTc-HL91 uptakes in tumors were determined by serial imaging, biodistribution, and autoradiography. RESULTS: 99mTc-HL91 uptake (ratio of ROItumor to ROIwhole body) in HLC ranged from 1.1 to 8.0%, and it did not show any response to radiation therapy. Major variations were observed in 99mTc-HL91 accumulation in MKN45 and KB-31; from 0.7 to 4.7%, and from 1.0 to 7.3%, respectively. Some tumors responded to radiotherapy, while others did not. Tumor response was not dependent on the 99mTc-HL91 uptake, tumor size or radiation dose. Comparing 99mTc-HL91 uptake in tumors before (B) and after (A) their radiation, uptake (B) was always smaller than uptake (A) for HLC, and they did not respond to irradiation at all. For MKN45 and KB-31, tumors responded to radiation when their uptake (A) was not higher than uptake (B). In contrast, the tumors continued to grow when their uptake (A) was higher than uptake (B). Sequential 99mTc-HL91 imaging of KB-31 and their autoradiography indicated that tumors whose 99mTc-HL91 uptakes was increased post irradiation were composed of mainly hypoxic cells. On the other hand, many viable areas were observed in tumors when the increase in 99mTc-HL91 uptake was relatively small. CONCLUSION: 99mTc-HL91 uptake in tumors did not always relate to their sensitivities to radiation therapy. Sequential 99mTc-HL91 imagings post irradiation showed that the increase in 99mTc-HL91 uptake in tumors predicted a poor response to radiation therapy, and that a decrease or no change suggested that radiation therapy would be effective. Monitoring by 99mTc-HL91 imaging is a good tool to predict the radiosentivities of tumors.     

Neuroblastoma: imaging evaluation by sequential Tc-99m MDP, I-131 MIBG, and Ga-67 citrate studies

Fourteen children with histopathologically confirmed neuroblastoma underwent sequential correlative imaging studies using I-131 MIBG, Tc-99m MDP, and Ga-67 citrate during various stages of the disease. Of the patients 86% showed I-131 MIBG accumulation in the primary tumoral site, whereas 71% showed Tc-99m MDP and 79% Ga-67 citrate uptake. In 86% at least one of the two latter radiopharmaceuticals concentrated in the primary tumor. The use of all three radiopharmaceuticals raised the detection rate to 93%. Of the osseous or extraosseous metastases 100% were detected by Tc-99m MDP studies. The I-131 MIBG studies were positive in 71% of the osseous metastases and in 70% of the extraosseous metastases. No Ga-67 citrate uptake was demonstrated in osseous metastases, although one extraosseous lung metastasis concentrated this radiopharmaceutical. Tc-99m MDP bone imaging was the best method for diagnosing metastatic spread of the disease and for monitoring the results of treatment. Primary tumor uptake was best indicated by I-131 MIBG. Both Ga-67 citrate and I-131 MIBG were superior to Tc-99m MDP with regard to accurately demonstrating the extent of primary tumors. Only Tc-99m MDP indicated the relationship of these tumors to the kidneys and neighboring osseous structures, providing early screening of kidney compression. Ga-67 citrate study was mainly indicated in tumors with catecholamine depletion, which failed to concentrate the other two radiopharmaceuticals. I-131 MIBG proved especially useful in detecting neuroblastoma with negative Tc-99m MDP and Ga-67 citrate studies and also proved to be helpful with those cases in which I-131 MIBG was planned for therapy. The following strategy is suggested for evaluating neuroblastoma.(ABSTRACT TRUNCATED AT 250 WORDS)     

儿童骨外软组织肿瘤摄取99Tcm-MDP的特点与肿瘤组织病理学的关系

目的 探讨肿瘤患儿骨显像中骨外软组织肿瘤摄取99Tcm-亚甲基二膦酸盐（MDP）的特点,以及其与肿瘤组织病理学的关系。 方法 回顾性分析2008年12月至2018年12月在上海交通大学医学院附属新华医院和同济大学附属第十人民医院行骨显像的33例肿瘤患儿的临床资料,其中男患儿21例、女患儿12例,年龄3个月~10岁。根据病理学结果将肿瘤类型分为母细胞瘤、间叶组织肿瘤和生殖细胞肿瘤3大类。根据骨显像等影像学结果,将骨外软组织肿瘤的最高放射性浓聚程度从低到高分为“+”、“++”和“+++”, 分析骨显像的特点及其与肿瘤病理学的关系。软组织肿瘤摄取99Tcm-MDP的多组间比较采用Kruskal-Willis H秩和检验。 结果 33例患儿中母细胞瘤26例（78.8%,包括神经母细胞瘤15例、肾母细胞瘤6例、肝母细胞瘤4例和胰母细胞瘤1例）、间叶组织肿瘤5例（15.2%,包括骨肉瘤肺转移灶3例、恶性肾外横纹肌样瘤1例和左大腿脉管瘤1例）和生殖细胞肿瘤2例（6.0%）,软组织肿瘤的3种类型摄取99Tcm-MDP程度的差异无统计学意义（H=1.993,P=0.369）。所有患儿骨外软组织肿瘤骨显像内部特点为钙化、坏死和其他特点（含有骨化基质或实性肿块无明显坏死及钙化）,摄取99Tcm-MDP为“+” 的6例（6/33,18.2%）、 “++”的11例（11/33,33.3%）和 “+++”的16例（16/33,48.5%）,肿瘤内钙化伴坏死、钙化、坏死和其他原因引起的99Tcm-MDP摄取程度的差异无统计学意义（H=2.313,P=0.315）。不同病理类型的肿瘤摄取99Tcm-MDP为“+”的6例（18.2%,包括母细胞瘤5例、间叶组织肿瘤1例）、“++”的11例（33.3%,包括母细胞瘤9例、间叶组织肿瘤2例）和“+++”的16例（48.5%,包括母细胞瘤12例、间叶组织肿瘤2例、生殖细胞肿瘤2例）。 结论 骨显像时患儿骨外软组织肿瘤摄取99Tcm-MDP多提示为恶性肿瘤,以神经母细胞瘤最常见,其程度与组织病理学分类无明显相关性。     

Unusual extraosseous tumoral accumulation of 99mTc-MDP

Three cases (rhabdomyosarcoma, lymphoma, and metastatic malignant melanoma) of unexpected increased uptake of methylenediphosphonate labelled by technetium 99m sodium pertechnetate (^99mTc-MDP) are described. The possible mechanisms of the extraosseous tumoral accumulation of ^99mTc-MDP in these malignancies are discussed. The usefulness of this method for the diagnosis, localization, and follow-up of some extraosseous tumors is evaluated.     

Intense bone imaging agent uptake in the soft tissues of the lower legs and feet relating to ischemia and cold exposure

We present a patient with diffuse and intense uptake in the soft tissues of both lower legs and feet seen on ^99mTc-HMDP bone scintigraphy. This finding presumably resulted from compromised blood supply to the lower legs plus a cold environment. The extraosseous bone imaging agent localization was presumably related to an existing ischemic condition that was exacerbated by cold. Differential diagnosis of the scan pattern should be differentiated from the artifact of socks contaminated by radioactive urine.     

The complementary role of sequential 99mTc-MDP and 67Ga-citrate scanning in the diagnosis and follow-up of neuroblastoma

Fourteen children with histopathologically confirmed neuroblastoma underwent 38 studies using ^99mTc-methylene-diphosphonate (MDP) and galliumcitrate Ga67 whole-body scintigraphy during various stages of the disease. Ten patients (71%) showed ^99mTc-MDP accumulation in the primary tumoral site, whereas 11 patients (78.6%) showed ⁶⁷Ga concentration. In 12 patients (86%), at least one of these two radiopharmaceuticals concentrated in the primary tumor. Nine patients had osseous or extraosseous metastases. All of these metastases (100%) were positive on ^99mTc-MDP sctintigraphy. No ⁶⁷Ga-citrate uptake was demonstrable in osseous metastases; only one extraosseous lung metastasis concentrated this radiopharmaceutical. ⁶⁷Ga-citrate was superior to ^99mTc-MDP with regard to accurately demonstrating the extent of primary tumors. Only ^99mTc-MDP indicated the relationship of the tumor to the kidneys and neighbouring osseous structures, prividing early screening of kidney compression and possible damage caused by the tumor. From these results, we found these two methods to be complementary for the diagnosis and follow-up of neuroblastoma; their combined use resulted in high diagnostic accuracy and a considerable gain of information. We therefore recommend sequential ^99mTc-MDP and ⁶⁷Ga-citrate scans for the diagnosis and evaluation of the primary tumor; periodic ^99mTc-MDP wholebody scans should be used in the follow-up of treatment, and for discovering disease exacerbations and metastases.Presented in part in the European Congress of Nuclear Medicine, London, England, September 1985     

Development of a novel 99mTc-chelate-conjugated bisphosphonate with high affinity for bone as a bone scintigraphic agent.

In bone scintigraphy using (99m)Tc with methylenediphosphonate ((99m)Tc-MDP) and hydroxymethylenediphosphonate ((99m)Tc-HMDP), it takes 2-6 h after an injection before imaging can start. This interval could be shortened with a new radiopharmaceutical with higher affinity for bone. Here, based on the concept of bifunctional radiopharmaceuticals, we designed a (99m)Tc-mercaptoacetylglycylglycylglycine (MAG3)-conjugated hydroxy-bisphosphonate (HBP) ((99m)Tc-MAG3-HBP) and a (99m)Tc-6-hydrazinopyridine-3-carboxylic acid (HYNIC)-conjugated hydroxy-bisphosphonate ((99m)Tc-HYNIC-HBP). METHODS: (99m)Tc-MAG3-HBP was prepared by complexation of MAG3-HBP with (99m)Tc using SnCl(2) as a reductant. The precursor of (99m)Tc-HYNIC-HBP, HYNIC-HBP, was obtained by deprotection of the Boc group after the coupling of Boc-HYNIC to a bisphosphonate derivative. (99m)Tc-HYNIC-HBP was prepared by a 1-pot reaction of HYNIC-HBP with (99m)TcO(4)(-), tricine, and 3-acetylpyridine in the presence of SnCl(2). Affinity for bone was evaluated in vitro by hydroxyapatite-binding assays for (99m)Tc-HMDP, (99m)Tc-MAG3-HBP, and (99m)Tc-HYNIC-HBP. Biodistribution experiments for the 3 (99m)Tc-labeled compounds were performed on normal rats. RESULTS: (99m)Tc-MAG3-HBP and (99m)Tc-HYNIC-HBP were each prepared with a radiochemical purity of >95%. In the in vitro binding assay, (99m)Tc-MAG3-HBP and (99m)Tc-HYNIC-HBP had greater affinity for hydroxyapatite than (99m)Tc-HMDP. In the biodistribution experiments, (99m)Tc-MAG3-HBP and (99m)Tc-HYNIC-HBP had higher levels of radioactivity in bone than (99m)Tc-HMDP. (99m)Tc-MAG3-HBP was cleared from the blood slower than (99m)Tc-HMDP, whereas there was no significant difference in clearance between (99m)Tc-HYNIC-HBP and (99m)Tc-HMDP. Consequently, (99m)Tc-HYNIC-HBP showed a higher bone-to-blood ratio than (99m)Tc-HMDP. CONCLUSION: We developed a novel (99m)Tc-chelate-conjugated bisphosphonate with high affinity for bone and rapid clearance from blood, based on the concept of bifunctional radiopharmaceuticals. The present findings indicate that (99m)Tc-HYNIC-HBP holds great potential for bone scintigraphy.     

The detection of local recurrent head and neck cancer with fluorine-18 fluorodeoxyglucose dual-head positron emission tomography.

Primary tumors of the larynx and hypopharynx are preferably treated with high-dose radiation therapy. In these patients, it may be difficult to distinguish recurrent disease from post-treatment reactions. The aim of the present study was to assess the value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in the detection of local relapses of laryngeal or hypopharyngeal carcinoma after radiotherapy using a dual-head PET camera. Forty-eight patients (43 male, 5 female; mean age +/-SD, 61+/-9.5 years) with suspected recurrent laryngeal or hypopharyngeal cancer were prospectively studied. The mean interval between initial treatment and suspicion of recurrent disease was 14.6 months (range: 3-100 months). FDG dual-head PET was followed by endoscopy with or without biopsy under general anaesthesia within a period of 2 months in all patients. The mean period of follow-up after FDG dual-head PET was 13.7 months. In 19 out of 31 patients with focally increased uptake, tumour recurrence (mean diameter: 2.4 cm; range 0.4-6.5 cm) was found at initial endoscopy. In five patients recurrence was found during follow-up with a mean interval of 6.6 months. Seven patients had a false-positive study due to benign lesions or swallowing artefacts. In none of the patients with a normal PET study was tumour recurrence found during follow-up. The sensitivity and specificity of FDG dual-head PET were 100% and 71%, respectively. It is concluded that FDG dual-head PET is highly sensitive for the detection of local recurrence of laryngeal and hypopharyngeal carcinoma after radiotherapy. Some lesions were detected with a mean interval of 6.6 months before histological confirmation. In patients suspected of having recurrent laryngeal or hypopharyngeal cancer in whom FDG-PET is negative, endoscopy may be omitted for at least 6 months and possibly for up to 1 year.     

Usefulness of 99mTc-pertechnetate single-photon emission computed tomography in remnant mass estimation of postsurgical patients of differentiated thyroid cancer during internal dosimetry

OBJECTIVE: No satisfactory methods exist for postsurgical remnant mass estimation required for dosimetric calculations in differentiated thyroid cancer patients undergoing I-131 remnant ablation. We estimated the remnant mass by Tc-99m pertechnetate single-photon emission computed tomography to calculate the radiation dose delivered. MATERIALS AND METHODS: Thyroid phantoms of known volumes (1.1-6 cm3) were fabricated, filled with different concentrations of Tc-99m pertechnetate activity, and single-photon emission computed tomography acquired on a dual head camera and processed with Hanning filter. Area of the organ on coronal slices was calculated at different thresholds and the sum was multiplied by slice thickness to get the volume. A threshold of 50% was found to distinguish the organ from the background activity and give the most accurate results. Remnant mass was calculated by this method in 50 patients of differentiated thyroid cancer after thyroid surgery. Effective half-life (EHL) of I-131 and 24 h radioactive iodine uptake (RAIU) were calculated by repeated neck count measurements for 4 days. After administering I-131 for therapy, 39 patients were followed up at 6 months and the effects of various parameters in achieving complete ablation were analyzed. RESULTS: Mean values of remnant mass, RAIU, and EHL were 6.6+/-4.3 g, 8.8+/-6.1%, and 4.5+/-0.9 days, respectively. Type of surgery, remnant mass, and RAIU were the most important predictors of complete ablation (P<0.05). Radiation-absorbed dose, EHL, and the administered activity had no significant effect on complete ablation. CONCLUSION: Remnant thyroid mass estimation by Tc-99m pertechnetate single-photon emission computed tomography is a simple technique and allows overcoming the dependence on structural imaging techniques or making empirical assumptions during dosimetry.     

Tc-99m MIBI to evaluate children with Ewing's sarcoma

PURPOSE: Tc-99m MIBI has been used increasingly to evaluate benign and malignant tumors because of its tumor-seeking properties and ability to provide an imaging assessment of multiple-drug resistance. This study investigated the clinical utility of Tc-99m MIBI in the management of Ewing's sarcoma in children. METHODS: Thirteen Tc-99m MIBI studies in nine (six male, three female) patients ages 6.5 to 20 years (mean, 13.4 years) with Ewing's sarcoma were reviewed. All patients had imaging studies at diagnosis, and four had follow-up studies during or after therapy. Scintigraphy was evaluated for Tc-99m MIBI uptake within the tumor and in metastases, which other imaging modalities had shown to be present in four patients. Scintigraphic results were correlated with the clinical course in all patients and with tumor P-glycoprotein status in six patients. RESULTS: Tc-99m MIBI accumulated in 6 of 9 primary tumors and did not accumulate in one recurrent tumor. No metastases showed Tc-99m MIBI uptake. The presence or absence of Tc-99m MIBI uptake at diagnosis or after therapy carried no prognostic significance. Tc-99m MIBI was present in the two tumors that were P-glycoprotein positive and in only one of four tumors that were P-glycoprotein negative. CONCLUSION: Tc-99m MIBI imaging does not appear to be useful in Ewing's sarcoma.     

鼻咽癌放射治疗后~(99m)Tc-MIBI SPECT显像的临床价值

目的:评价99mTc-MIBI SPECT显像对鼻咽癌患者放疗后局部残余或复发病灶的鉴别价值。方法:48例经病理证实的原发性鼻咽癌患者于放疗后3个月行99mTc-MIBI SPECT显像,与同期的CT结果对照,并分别计算鼻咽部与头皮的放射性计数比值作为99mTc-MIBI摄取指数(MUI)。以接受器工作特性曲线(ROC)分析确定MUI判别阈值。鼻咽内镜检查、病理活检及18个月的临床随访资料作为鼻咽癌病灶残余或鼻咽癌复发的依据。结果:以MUI≥1.33为阳性标准,99mTc-MIBI SPECT显像监测鼻咽癌病灶残余或复发的敏感度73.33%,特异度93.94%,诊断符合率87.50%。CT监测鼻咽癌病灶残余或复发的敏感度73.33%,特异度84.85%,诊断符合率81.25%。99mTc-MIBI SPECT显像与CT联合鉴别鼻咽癌病灶残余或复发的敏感度、特异度和诊断符合率分别为100%、96.55%和97.30%。结论:99mTc-MIBI SPECT显像对鼻咽癌患者放疗后局部残余或复发病灶的鉴别有一定价值;与CT联合可有效提高对放疗后鼻咽癌病灶残余或复发的早期诊断效能。     

Evidence for early and persistent impairment of salivary gland excretion after irradiation of head and neck tumours

Salivary gland scintigraphy with technetium-99m pertechnetate was used to follow changes in the excretion and uptake function of the major salivary glands until 1 year after irradiation. Twenty-five patients who received radiotherapy for head and neck tumours were included in the study. Seventy-nine salivary glands (39 parotid and 40 submandibular) were evaluated in relation to the average received radiation dose. Salivary gland scintigraphy was performed before and 1, 6 and 12 months after radiotherapy. For each gland the excretion response to carbachol, evaluated by calculation of the salivary excretion fraction (SEF), the cumulative gland uptake (CGU) and the absolute excreted activity (AEA) at various intervals after radiotherapy were compared with the baseline values. The excretion response decreased in 20 of 25 patients at 1 month after radiotherapy. One month after radiotherapy both SEF and AEA decreased significantly in relation to the radiation dose. These decreases in excretion parameters persisted during the follow-up period. Parotid excretion was affected significantly more than submandibular excretion. CGU values did not change significantly until 6 months after radiotherapy, but at 12 months a significant decrease related to radiation dose was observed. Xerostomia was assessed during radiotherapy and on the days of the scintigraphic tests. The incidence of xerostomia did not correspond to the effects observed in the scintigraphy studies. It is concluded that radiotherapy induces early and persistent impairment of salivary gland excretion, related to the radiation dose. This impairment is stronger in parotid glands than in submandibular glands.     

The detection of local recurrent head and neck cancer with fluroine-18 fluorodeoxyglucose dual-head positron emission tomography

Primary tumors of the larynx and hypopharynx are preferably treated with high-dose radiation therapy. In these patients, it may be difficult to distinguish recurrent disease from post-treatment reactions. The aim of the present study was to assess the value of fluorine-18 fluorodeoxyglucose positron emission tomography (FDG-PET) in the detection of local relapses of laryngeal or hypopharyngeal carcinoma after radiotherapy using a dual-head PET camera. Forty-eight patients (43 male, 5 female; mean age ±SD, 61±9.5 years) with suspected recurrent laryngeal or hypopharyngeal cancer were prospectively studied. The mean interval between initial treatment and suspicion of recurrent disease was 14.6 months (range: 3–100 months). FDG dual-head PET was followed by endoscopy with or without biopsy under general anaesthesia within a period of 2 months in all patients. The mean period of follow-up after FDG dual-head PET was 13.7 months. In 19 out of 31 patients with focally increased uptake, tumour recurrence (mean diameter: 2.4 cm; range 0.4–6.5 cm) was found at initial endoscopy. In five patients recurrence was found during follow-up with a mean interval of 6.6 months. Seven patients had a false-positive study due to benign lesions or swallowing artefacts. In none of the patients with a normal PET study was tumour recurrence found during follow-up. The sensitivity and specificity of FDG dual-head PET were 100% and 71%, respectively. It is concluded that FDG dual-head PET is highly sensitive for the detection of local recurrence of laryngeal and hypopharyngeal carcinoma after radiotherapy. Some lesions were detected with a mean interval of 6.6 months before histological confirmation. In patients suspected of having recurrent laryngeal or hypopharyngeal cancer in whom FDG-PET is negative, endoscopy may be omitted for at least 6 months and possibly for up to 1 year. Received 27 January and in revised form 15 March 1999     

Extraosseous accumulation of<Superscript>99m</Superscript>Tc-MDP in lymph node metastases of small cell carcinoma of the esophagus

We report a case of esophageal carcinoma that showed extraosseous accumulation of 99mTc-MDP in lymph node metastases to the cervical and paracardial lymph nodes. There are few cases showing abnormal extraosseous accumulation of 99mTc-MDP in esophageal cancer lesion. The patient was a 53-year-old man with advanced esophageal cancer. Bone scintigraphy demonstrated extraosseous accumulations in left supraclavicular and paracardial lymph node metastases. The histopathological diagnosis was small cell carcinoma of the esophagus, which is a rare disease with aggressive behavior and poor prognosis. Our patient underwent 2 courses of systemic chemotherapy (CDDP + VP16), but died of rapidly growing systemic metastases 5 months after the initial treatment.     

The complementary role of sequential 99mTc-MDP and 67Ga-citrate scanning in the diagnosis and follow-up of neuroblastoma

Fourteen children with histopathologically confirmed neuroblastoma underwent 38 studies using 99mTc-methylene-diphosphonate (MDP) and galliumcitrate Ga67 whole-body scintigraphy during various stages of the disease. Ten patients (71%) showed 99mTc-MDP accumulation in the primary tumoral site, whereas 11 patients (78.6%) showed 67Ga concentration. In 12 patients (86%), at least one of these two radiopharmaceuticals concentrated in the primary tumor. Nine patients had osseous or extraosseous metastases. All of these metastases (100%) were positive on 99mTc-MDP scintigraphy. No 67Ga-citrate uptake was demonstrable in osseous metastases; only one extraosseous lung metastasis concentrated this radiopharmaceutical. 67Ga-citrate was superior to 99mTc-MDP with regard to accurately demonstrating the extent of primary tumors. Only 99mTc-MDP indicated the relationship of the tumor to the kidneys and neighbouring osseous structures, providing early screening of kidney compression and possible damage caused by the tumor. From these results, we found these two methods to be complementary for the diagnosis and follow-up of neuroblastoma; their combined use resulted in high diagnostic accuracy and a considerable gain of information. We therefore recommend sequential 99mTc-MDP and 67Ga-citrate scans for the diagnosis and evaluation of the primary tumor; periodic 99mTc-MDP whole-body scans should be used in the follow-up of treatment, and for discovering disease exacerbations and metastases.     

Altered regional clearance of 99Tcm-DTPA in radiation pneumonitis.

99Tcm-diethylene triaminepenta-acetic acid (99Tcm-DTPA) lung scintigrams were investigated in 11 patients with radiation pneumonitis to assess the alteration of clearance of this small solute. Thirty minutes after the injection of 99Tcm-DTPA, all 11 patients showed abnormal accumulation. This uptake was seen in the areas with reduced 99Tcm-macroaggregated albumin activity. The curves of the lung/heart ratios obtained after 1 min after injection of 99Tcm-DTPA in areas showing abnormal accumulation were of three types. Comparison of the slope for the initial 5 min of the lung/heart curves between the abnormal accumulation sites and the contralateral non-irradiated lung revealed a significant difference. The uptake ratio (the mean counts of the last frame divided by initial peak count) was related to the degree of abnormal accumulation in the radiation pneumonitis. Moreover, study of rabbits with radiation pneumonitis revealed similar behaviour by 99Tcm-DTPA as observed clinically. This simple and rapid method may be useful in detecting and monitoring the altered regional kinetics of 99Tcm-DTPA in radiation pneumonitis.     

Utility of Tc-99m human polyclonal immunoglobulin G scintigraphy for assessing the efficacy of yttrium-90 silicate therapy in rheumatoid knee synovitis

PURPOSE: The aim of this study was to determine the utility of Tc-99m human polyclonal immunoglobulin G (HIG) scintigraphy for evaluating the efficacy of yttrium-90 (Y-90) silicate therapy in rheumatoid knee synovitis. MATERIALS AND METHODS: Fifteen patients (13 women, 2 men; mean age, 53.5 +/- 8.4 years) with rheumatoid arthritis had radionuclide synovectomy using 185 MBq (5 mCi) Y-90 silicate to evaluate 24 knee joints with chronic persistent synovitis. Radiologic and clinical evaluations and Tc-99m HIG scans were performed in each patient before radionuclide synovectomy. Each patient was reassessed 3, 6, 9, and 12 months after therapy using clinical examination and Tc-99m HIG scintigraphy. RESULTS: In 14 of 24 knee joints (4 Larsen stage I, 10 Larsen stage II) that had excellent or good clinical responses to Y-90 silicate therapy, the Tc-99m HIG index values 3 months after treatment were significantly lower than the pretreatment index values (P < 0.001). In 13 of these 14 joints, these low index values and clinical results remained constant throughout the 1 year of follow-up. One patient (1 of the 14 knee joints) experienced severe pain and swelling as a result of recurrent arthritis at 9 months, and the Tc-99m HIG index value increased at 9 months and remained high 12 months after therapy. In 10 of 24 knee joints (4 Larsen stage II, 6 Larsen stage III) that had a fair or poor clinical response, Tc-99m HIG index values were statistically similar before and after radionuclide therapy. CONCLUSIONS: Quantitative Tc-99m HIG scintigraphy is a valuable method for assessing the efficacy of Y-90 silicate therapy in rheumatoid knee synovitis.     

99 Tcm-MIBI SPECT在原发性鼻咽癌诊断、放疗后残余或复发监测中的应用

目的：评价^99Tc^m-甲氧基异丁基异腈(MIBI)SPECT显像对原发性鼻咽癌的诊断和鼻咽癌放疗后局部残余或复发的鉴别价值。方法：20例经病理检查证实的原发性鼻咽癌患者于治疗前、放疗后3和6个月分别行^99Tc^m-MIBI SPECT显像，与同期CT和(或)MRI结果对照，分别计算肿瘤或正常鼻咽部与头皮的放射性计数比值，作为^99Tc^m-MIBI摄取指数(MUI)。以接受器工作特性(ROC)曲线确定MUI判别阈值。以鼻咽部内镜检查、病理活组织检查及18个月的临床随访资料作为鼻咽癌残余或复发的依据。结果以MUI≥2．15为阳性标准，^99Tc^m-MIBISPECT显像诊断原发性鼻咽癌的灵敏度、特异性和准确性均为95％。以MUI≥1．32为阳性标准，^99Tc^m-MIBI SPECT显像监测鼻咽癌残余或复发的灵敏度为3／4例，特异性93．8％，准确性90．0％。CT和(或)MRI监测鼻咽癌残余或复发的灵敏度为3／4例，特异性81．3％，准确性80．0％。^99Tc^m-MIBISPECT显像与CT和(或)MRI联合鉴别鼻咽癌残余或复发的灵敏度、特异性和准确性分别为2／2例、92．9％和93．8％。结论:^99Tc^m-MIBI SPECT显像对确定鼻咽癌原发灶范围有一定价值；与CT和(或)MRI联合，可提高对放疗后鼻咽癌残余或复发的早期诊断效能。