Radiolabeled localization of the sentinel lymph node: dosimetric evaluation in personnel involved in the procedure

AIMS AND BACKGROUND: Peritumoral injection of 99mTc-labeled colloids for lymphoscintigraphy and radioguided surgery does not entail any relevant radiation burden to the patients. The real issue about radiation protection concerns the personnel involved in the procedure besides the nuclear medicine personnel. The aim of our study was to evaluate the cumulative doses to personnel involved during the injection of radiolabeled compounds, under ultrasound or stereotactic guidance and the radiation burden to the personnel involved in the surgical incision of the tumor 24 hours after the administration of 99mTc-labeled colloids. METHODS AND STUDY DESIGN: We performed environmental contamination tests (SMEAR TEST) and exposure evaluation in the operating room. RESULTS: In the operating room the removed activity in the analyzed samples was less than 0.5 Bq/g and exposure to the personnel was less than 6 micro Sv/h. The evaluations made during ultrasound guidance demonstrated an equivalent and effective dose less than 20 microSv. CONCLUSIONS: Our results show that during ultrasound or stereotactic administration of radiolabeled compounds the radiation burden to the personnel involved in the procedure is virtually negligible. The surgeons too are exposed to a negligible radiation dose.     

Sentinel lymph node identification in breast cancer: feasibility study

The aim of the study was to evaluate in our institute the technique of sentinel node (SN) identification and biopsy in the surgical treatment of early breast cancer. Between June 1998 and November 1999 54 patients (age range, 31-75 years) where studied. Inclusion criteria were age less than 75 years, indication for conservative surgery, absence of palpable axillary nodes, Karnofksy index >70. Lymphoscintigraphy was performed 16-18 hours prior to surgery, following injection of 0.1-0.2 mL of 99mTc-Nanocoll: the administered activity was 3-4 MBq in group A (44 pts) and 7-8 MBq in group B (10 pts). The colloids were administered by transdermal supralesional injection in 49 patients with palpable nodules and by intraparenchymal ultrasound-guided injection in five patients with non-palpable nodules. Planar projections were performed starting from the 5th until the 80th min (or 180th in the event of late migration). In 10 patients further projections were acquired 14-18 h following tracer administration. All nodes identified by gamma probe (MR 100 Pol.Hi.Tech) were histologically evaluated by immunohistochemistry and standard histology. Scintigraphic visualization of the SN was obtained in 49 patients: in 38 of these patients there was only one SN while in 11 patients there were two or three SNs. The delayed scan made in 10 patients did not show any further nodes. In all patients given US-guided perilesional injections migration was late (after at least 60 min). Our study confirms the validity of the scintigraphic procedure, its safety for patients and health care workers, and the feasibility of interdisciplinary collaboration.     

Sentinel lymph node technique for breast cancer: radiation safety issues

The radiation safety issues in the application of radioguided sentinel lymph node (SLN) biopsy are discussed, particularly the effective dose (ED) for patients undergoing lymphoscintigraphy by taking into account both the internal emission and the external transmission dose. The quantitative result can be compared with other common radiological examinations. Whole body and finger doses of surgical and pathology staff were determined by direct measurement using high-sensitivity thermoluminescent dosimeters (TLDs) and compared with the annual dose limits recommended by the International Commission on Radiological Protection (ICRP). These dosimetric observations for personnel also provide reference information to implement guidelines for the safe handling, storage, and transport of radioactive specimens at all stages of the radioguided surgery effort in order to maintain good work practices while dealing with unsealed radioactive substances.     

Personnel radiation exposure analysis in a radiotherapy center: Fourteen year retrospective study

The radiation exposure to the staff in the Ontario Cancer Institute between 1964–1977 was analyzed based on data from personnel film monitors. The annual collective dose equivalent was found to vary from 320 to 720 person-mSv. Of this, about 75% was attributable to the use of radionuclides for intracavitary and interstitial therapy, about 17% the use of external radiation therapy equipment, and the remaining, about 8% was equally attributable to diagnostic X ray and a mixture of many radiation sources used in research. The most influential factor to the annual collective dose equivalent was the number of patients treated with intracavitary and interstitial therapy. The dose per such application to this population was about .70 mSv, and was further broken down into .48 mSv to nurses in the wards where these patients were admitted, .11 mSv to personnel who handle these sources, .08 mSv to the operating room staff, and .04 mSv to the others. The collective dose per external radiation daily treatment was about .0008 mSv. For a course of 20 treatments, the collective dose equivalent will be in the order of .02 mSv. For diagnostic radiology, the collective dose per patient visit was in the order of 0.0003 mSv.     

125I粒子植入术后辐射防护的最优化研究

目的:通过检测自行设计的含铅穿戴用品对125I粒子植入患者的放射性屏蔽效果,优化辐射防护的个体化方法。方法:125I粒子植入患者69例,术后根据粒子植入的部位和数量选择穿戴不同类型的含铅防护用品。术后24小时内检测患者无屏蔽与穿戴不同铅当量屏蔽用品在不同距离的辐射剂量,并按接触时间计算与患者密切接触的病区医务人员（AAED)及陪护人员（AED）所接受的辐射剂量。结果:患者无屏蔽时,在0.5 m处的医务人员所受的年平均辐射剂量小于放射工作人员限值20 mSv,在2 m处接近公众限值1 mSv,在4 m处接近本底;在1 m处的陪护人员所受的平均辐射剂量接近公众限值1 mSv,在4 m处接近本底。患者穿戴0.25 mmPb含铅屏蔽用品时,零距离有58位患者的辐射剂量高于本底,但对医务及陪护人员产生的平均辐射剂量接近公众限值,其中最高者为1.8 mSv;穿戴0.5 mmPb含铅屏蔽用品时,患者零距离辐射剂量接近本底。结论:125I粒子植入后,患者穿戴0.25 mmPb含铅屏蔽用品时,绝大部分（68/69例）患者不会对医务及陪护人员造成辐射损伤;粒子植入数量较多和/或植入部位距体表较近的患者,若穿戴0.25 mmPb的屏蔽用品在0.3 m处辐射剂量大于本底,则应穿戴0.5 mmPb的含铅屏蔽用品。     

Sentinel node biopsy in 70 unselected patients with breast cancer: increased feasibility by using 10 mCi radiocolloid in combination with a blue dye tracer.

AIMS: Lymphatic mapping and sentinel node (SN) biopsy in breast cancer contribute to more accurate staging, while using less invasive techniques. The aim of this study is to improve the accuracy and feasibility of this concept, increasing the identification rate of the SN, by using an alternative technique. METHODS: In 70 unselected patients with primary breast cancer, of whom 51% had undergone previous excisional biopsy, lymphatic mapping was performed using 10 mCi (370 MBq) 99mTc-nanocolloid peritumorally, combined with an intradermal blue dye tracer. RESULTS: Lymphoscintigraphy showed one or more SN in 97% and harvest of the SN was possible in all patients (identification rate 100%). Axillary metastases were found in 39%. Sensitivity of the SN biopsy was high, both after primary surgery (93%) and after previous surgery (100%). Internal mammary lymph node biopsy following lymphatic mapping was attempted in all 24 patients (34%) with parasternal SN visible on the scan and was successful in 15 patients, revealing metastatic involvement in five patients. CONCLUSIONS: We conclude that SN biopsy, using a higher dose of peritumoral radiocolloid tracer, combined with intradermal blue dye tracer, increases feasibility in breast cancer, making this concept applicable for all patients with primary breast cancer.     

Sentinel node and radioguided surgery in breast cancer of limited size. Preliminary experience at ASL 1, Massa e Carrara

The aim of this study was to evaluate the effectiveness of sentinel node (SN) biopsy in breast cancer. Twenty-five female patients classified as T1N0 according to the TNM system of the UICC were evaluated with this procedure from April to October 1999. The day before surgery a subdermal injection of 99mTc-nanocoll within the tissue overlying the neoplastic lesion and subsequent lymphoscintigraphy were performed. In all patients the SN was detected with a radioguided probe during scintigraphy and surgery. Histological examination of the SN for detection of metastases was positive in four patients who subsequently underwent axillary dissection. In the remaining patients with normal SNs no axillary dissection was performed. The preliminary results confirm the validity of the sentinel node procedure.     

'Low dose' 99mTc-Sestamibi for radioguided surgery of primary hyperparathyroidism.

AIM: In this study, we evaluated the efficacy of low dose (99m)Tc-Sestamibi administration for radioguided parathyroid surgery in patients with primary hyperparathyroidism (PHPT). METHODS: Three hundred consecutive PHPT patients were studied between September, 1999 and July, 2003. Pre-operative work-up included (99m)Tc-pertechnetate/(99m)Tc-Sestamibi subtraction scintigraphy and high resolution ultrasonography (US). 37MBq of (99m)Tc-Sestamibi was injected i.v. in the operating suite approximately 10 min prior to the beginning of the surgical procedure for intraoperative radiolocalization; quick parathyroid hormone (QPTH) assays were performed. RESULTS: Two hundred and seven of the 211 patients selected for minimally-invasive radioguided parathyroidectomy (MIRP) were successfully treated for a solitary parathyroid adenoma (PA) through a 2-2.5 cm skin incision (mean operative time 35 min, mean hospital stay 1.2 days). In the 89 patients selected for traditional bilateral neck exploration (BNE), radioguided surgery was not as successful in the identification of the PA, especially in patients with (99m)Tc-Sestamibi-avid thyroid nodules. Nevertheless, the combination of probe and QPTH measurement was very helpful in patients with multigland disease. CONCLUSIONS: Low-dose (99m)Tc-Sestamibi administered few minutes before surgery is sufficient for MIRP in patients with high likelihood of a solitary PA and without concomitant (99m)Tc-Sestamibi-avid thyroid nodules. The combination of radioguided surgery and QPTH measurements is very useful in the early identification of unanticipated multigland disease.     

Sentinel lymph node and breast cancer staging: final results of the Turin Multicenter Study

AIM OF THE STUDY: Validation of the sentinel node (SN) technique in breast cancer by means of lymphoscintigraphy. MATERIALS AND METHODS: From December 1996 to January 1999 102 T1-T2 breast carcinoma cases were recruited in Turin. 99mTc-human serum albumin colloids were injected subdermally the day before surgery (mean activity, 5.2 +/- 2.5 MBq). Scintigraphic imaging was performed after injection. After identification of the SN during surgery by a hand-held gamma probe, the SN was excised and sent for histologic examination. SN histology was compared with that of other axillary nodes. RESULTS: The SN detection rate was 86.3%; among 88 cases with an identified SN, 37 (42%) had axillary metastases; the SN was metastatic in 35 cases (sensitivity, 94.6%); in 51.3% of pN+ cases (19/37) the SN was the only metastatic site. In two of the 53 negative SNs, SN histology did not match with that of the remaining axilla (negative predictive value, 96.2%; staging accuracy, 97.7%). CONCLUSIONS: Our results agree with those reported in the literature; however, except in clinical trials and experienced structures axillary lymph node dissection should not be abandoned when mandatory for prognostic purposes, considering that at present SN biopsy alone is not completely accurate for axillary staging, especially in the absence of an adequate learning period.     

Sentinel node biopsy in skin melanoma patients--measurements of absorbed doses of radiation to the hands of medical staff

BACKGROUND AND OBJECTIVES: The goal of this study was to measure absorbed doses of radiation to the hands of medical staff performing sentinel node biopsy (SNB) in skin melanoma patients. METHODS: The study was conducted from January 2004 to May 2004, during SNBs (lymphoscintigraphy-(99m)Tc on albumin carrier, surgery after 24 hr; blue dye; intraoperative detection of gamma radiation) in 22 skin melanoma patients. During lymphoscintigraphy and surgical procedures, 57 highly sensitive thermoluminescent dosimeters (TLDs) were placed on different parts of the hands of the medical staff. RESULTS: Mean doses of radiation recorded on different parts of the hands of the physician injecting the radiotracer ranged from 2.43 to 84.11 microSv for single procedures, ranged from 3.20 to 5.84 microSv for the hands of surgeon, and ranged from 2.65 to 5.47 microSv for the hands of the remaining members of the medical staff. Absorbed doses of radiation to the hands of helping medical staff present in operating room was only slightly lower than absorbed doses to the hands of operating surgeon and assistant surgeon. CONCLUSION: The maximum recorded dose during this study was 1,900 times smaller than the current 1-year dose limit recommended by the International Commission on Radiological Protection (ICRP).     

99m Tc-HYNIC-TOC人体内照射剂量研究

背景与目的：放射性显像药物在人体内的剂量分布、各器官的吸收剂量及全身有效剂量数据非常重要。研究^99mTc标记的经肼基烟酰胺修饰的奥曲肽（^99mTc-Hydrazinonicotinyl-Tyr3-Octreotide,^99mTc-HYNIC-TOC）在人体内各器官的吸收剂量、全身吸收剂量及全身有效剂量。方法：对2018年5—6月复旦大学附属肿瘤医院收治的5例神经内分泌肿瘤患者静脉注射370 MBq^99mTc-HYNIC-TOC后于0.5、1.0、2.0、4.0和8.0 h行全身平面采集,其中2.0 h平面采集后即刻行全身断层采集。断层数据经迭代重建后,将数据导入GE Dosimetry Toolkit处理,在单光子发射计算机断层显像（single photon emission computedtomography,SPECT）/CT融合图像上勾画各器官生成感兴趣区（region of interest,ROI）,获得相应时间-活度曲线并计算曲线下面积得到滞留时间。依据美国核医学会医用内照射剂量学（Medical Internal Radiation Dose,MIRD）委员会提出的内照射剂量计算方法（MIRD体系）,利用OLINDA/EXM软件计算^99mTc-HYNIC-TOC在人体内各器官的吸收剂量、全身吸收剂量和全身有效剂量。结果：脾脏、膀胱、肾脏的单位活度吸收剂量较高,男性分别为0.042、0.019和0.016 mGy/MBq,女性分别为0.026、0.027和0.017 mGy/MBq。大脑、皮肤、甲状腺的单位活度吸收剂量较低,男性分别为0.000 3、0.000 5和0.000 5 mGy/MBq,女性分别为0.000 3、0.000 5和0.000 6 mGy/MBq。对放射线敏感的器官如骨原细胞、胸腺和红骨髓的单位活度吸收剂量均较低,范围为0.001 2~0.002 2 mGy/MBq。全身平均单位活度吸收剂量男性为0.001 7 mGy/MBq,女性为0.0016 mGy/MBq。全身单位活度有效剂量男性为0.004 58 mSv/MBq,女性为0.004 55 mSv/MBq。结论：^99mTc-HYNIC-TOC可安全地用于人体,其有效剂量低于允许范围上限。该研究结果可为临床安全使用^99mTc-HYNIC-TOC提供依据,也为其他放射性药物的安全性评估和加快临床转化提供新的可行方案。     

Blue dye versus combined blue dye-radioactive tracer technique in detection of sentinel lymph node in breast cancer.

BACKGROUND: Sentinel lymph node biopsy in breast cancer can be used to select patients in which axillary lymph node dissection could be avoided. In this study we compared the value of two methods for identification of sentinel node (SN) using either only blue dye or combination of blue dye and radioactive tracer. MATERIAL AND METHODS: All patients were women with clinically T(1-2)N(0)M(0) breast cancer. They were randomized into two groups. In Group A (50 patients) SN marking was performed only with blue dye and in Group B (100 patients) combined SN marking with blue dye and radiotracer was done. We used 2 ml of blue dye Patentblau V (Byk Gulden). Radiotracer was Antimony sulfide marked with Tc 99m and of 0.3 mCy (11.1 MBq) activity. Application method of both contrasts was peritumoral. After SN biopsy all patients underwent mastectomy or conservative surgery with axillary lymph node dissection of levels I and II. RESULTS: In Group A mean of 1.7 SNs were identified (median 1, range 1-4). False-negative rate in this group was 3/17 (17.6%) with negative-predictive value 20/23 (86.9%), sensitivity 14/17 (82%), specificity 20/33 (60%) and accuracy 34/50 (68%). In Group B mean number of SNs excised per case was 1.6 (median 1, range 1-5). False-negative rate was 2/44 (4.5%), negative-predictive value 41/43 (95.3%), sensitivity 42/44 (95%), specificity 41/56 (73%) and accuracy 83/100 (83%). The combination technique was significantly superior to blue-dye alone technique for negative-predictive value (p=0.033) and overall accuracy (p=0.048). CONCLUSIONS: The prediction of axillary lymph node status in breast cancer patients using combined technique has significantly higher accuracy than marking of SN with blue dye alone and therefore should be preferred.     

Subareolar injection of 99m-Tc sulfur colloid for sentinel nodes identification in multifocal invasive breast cancer

The objective were to study the relevance of the subareolar injection for sentinel node [SN] detection in multiple foci breast cancer. Seventy-nine patients with infiltrative breast carcinoma (diagnosed pre-operatively by core biopsy) and a mean age of 55 (31-78) years were enrolled. All patients were free of previous homolateral surgery, chemotherapy, locoregional radiotherapy or prevalent axillary lymph node. Using four 0.1 ml injections of 1.8 MBq, the technetium-99m 100 nm filtered sulfur colloid was injected by subareolar way (group I) in 16 cases of radiologically cancer with multiple invasive foci and 31 cases of radiologically unifocal cancer, and by peritumoral way (group II) in 32 cases of radiologically unifocal cancer. Scintigrams were obtained 2 to 4 hours after the injections and radioactive nodes were detected peroperatively 18 hours after the injection by intraoperative detection probe. Individual removal of all radioactive nodes was followed by axillary dissection at levels I and II of Berg including Rotter area control. All sentinel nodes were submitted to standard histopathological analysis on serial sections at 500 mu intervals completed by immunohistochemistry for cytokeratin on negative SN. SN were detected by scintigrams in 85% and 88% of the cases of group I and group II respectively, but in 98% and 97% of the cases of respectively both groups by intraoperative probe. Group I was composed of 69% ductal, 22% lobular and 9% tubular carcinomas, and group II of 87% ductal, 10% lobular and 3% tubular carcinomas. Seven and 5 radiologically unifocal tumors were in fact with multiple invasive foci at histology in groups I and II respectively. The complete scintigraphic procedure permitted the detection of a mean number of 2.7 (1-7) SN in group I and 2.3 (1-4) in group II (NS). In group I, the SN were metastatic in 22 patients (48%), 15 of them with the metastases being restricted to the SN, whereas in group II, the SN were metastatic in 9 patients (28%), 5 of them with the positivity restricted to the SN. No false negative result (SN negative and other axillary nodes positive) was observed in group I and only one false negative result in group II which was related to a cancer with histological multiple invasive foci. Sensitivities were 100% and 90%, and negative predictive values were 100% and 95%, for groups I and II respectively. Subareolar injection of radiocolloid allows identification of SN in cases of unifocal and multiple cancer. The mean number of SN detected by the subareolar method is not significantly different, although higher, to that detected by peritumoral injection.     

Sentinel node study in early breast cancer

Since October 1997 60 patients with early breast cancer (T <3 cm) were studied. All patients underwent lymphoscintigraphy with two types of colloid: the first (17 pts) with a particle size <1,000 nm; the second (43 pts) with a particle size <80 nm. The standard procedure consists of injection, on the day before surgery, of 70 MBq of the smaller nanocolloid in 0.4 cc saline divided over four sites, around the lesion or subdermally around the surgical scar. We utilize a low-energy, high-resolution LFOV camera for scintigraphy and a probe specific for the sentinel node during surgery. In 56/60 patients (93.3%) lymphoscintigraphy showed the sentinel node (SN). In two cases the SN was not detected presumably because of lymphatic interruption by an old surgical scar; in the other two cases the sites of injection were too close to the SN, thus masking it. In five cases (9%) the SN was not visualized with the surgical probe but in two of these drainage to the internal mammary chain was observed. The apparently lower sensitivity of intraoperative localization was due to the extra-axillary lymphatic drainage or to the vicinity of the SN to the primary lesion. The SN proved to be metastatic in 12 cases. No false-negative SNs were found. In five cases (10%) the radiolabeled lymph node was the only node containing tumor cells (micrometastases): this result depends on the combined use of hematoxylin-eosin and rapid cytokeratin staining. The application of blue dye was useful for easier identification of the SN but did not allow detection of more SNs. Our preliminary results are extremely encouraging. Considering that at the early stages of breast cancer the likelihood of lymph node metastases is low (20% in our series) and no false negative were reported in this study, we conclude that with SN biopsy axillary lymph node dissection can be avoided, making surgery less aggressive but maintaining accuracy.     

Biodistribution and dosimetry of (99m)Tc-depreotide (P829) in patients suffering from breast carcinoma

OBJECTIVE: This paper reports on the biodistribution and dosimetry of (99m)Tc-depreotide in patients. METHODS: Whole body planar images were acquired 30 minutes, 1, 2, 4, 9, and 24 hours after intravenous injection of 555-740MBq (99m)Tc-depreotide in 5 breast cancer patients. Urine was collected up to 24 hours after injection, allowing for a calculation of renal clearance and an interpretation of whole body clearance. Time activity curves were generated for the thyroid, lungs, liver, spleen, kidneys, colon, thoracic vertebrae/sternum, and whole body by fitting the organ-specific geometric mean counts, obtained from regions of interest (ROIs). The Medical Internal Radiation Dose (MIRD) formulation was applied to calculate the absorbed radiation dose for various organs. RESULTS: The whole body images show most of the activity distributed in the liver, spleen, and kidneys. Nearly all excretion of activity occurred by the renal system, and hepatobiliary excretion was negligible. Elimination of administered activity occurred predominantly through physical decay. The mean cumulative measured urinary excretion at 24 hours postinjection was 14.0% (standard deviation; 11.8%) of the administered activity. The highest absorbed dose was received by the kidneys, thyroid, and spleen. The average effective dose was estimated to be 1.15E-02mSv/MBq (standard deviation; 1.41E-03mSv/MBq). CONCLUSION: The biodistribution of (99m)Tc-depreotide demonstrated low lung and myocardial uptake allowing early imaging of the supradiaphragmatic region and this with a dosimetry favorable for clinical whole body and single photon emission computed tomography (SPECT) imaging.     

Sentinel node biopsy in cutaneous melanoma patients: technical and clinical aspects

The role of the patent blue dye (PBD) technique and intraoperative probe-guided lymphoscintigraphy (LS) in detecting the sentinel node (SN) was investigated in a group of 130 consecutive stage I cutaneous melanoma patients. The preoperative workup included high-resolution US scanning and LS performed 15-18 hours before surgery. On the basis of preoperative LS, in the group of examined patients a total of 143 lymphatic drainage basins were identified and surgically explored: 41.6% in the axilla, 52.8% in the groin, and 5.6% in the head/neck. A total of 228 SNs were intraoperatively detected and removed; 110 lymphatic basins contained histologically negative SNs, while 33 basins had metastatic SNs. The sensitivity for SN detection using PBD alone was 93%, while it was 100% when PBD was combined with intraoperative LS. Preoperative and intraoperative LS appears to be a highly sensitive technique for SN detection in cutaneous melanoma patients. Furthermore, in view of the limited skin incision when radioguided surgery is performed, SN biopsy could be feasible under local anesthesia.     

脂质体的局部淋巴结靶向富集

目的 探讨脂质体的局部淋巴结靶向性和富集性.方法 18只兔分为3组,每组6只.在兔双侧第一趾蹼皮下注射99mTc-氟尿嘧啶脂质体(99mTc-FL)各18.5 MBq,然后在注射后不同时间(第1组3 h,第2组6 h,第3组8 h)检测局部淋巴结、非引流淋巴结、血、尿、肝、脾、肺、肾、心、肠等组织的放射性.结果3、6和8 h组的每克局部淋巴结摄取率分别为(2.32±0.75)%、(5.37±1.73)%和(8.61±1.89)%(P＜0.05);3 h组每克局部淋巴结与非引流淋巴结、血、尿、肝、脾、肺、肾、心、肠等组织摄取率的均数比分别为232.00、16.57、23.20、29.00、19.33、25.78、46.40、46.40和25.78,6 h组分别为89.50、41.31、18.52、67.13、41.31、25.57、134.25、59.67和59.67,8 h组分别为86.10、61.50、16.56、53.81、57.40、10.01、107.63、107.63和86.10,差异有统计学意义(P＜0.01).结论 FL可经淋巴途径缓慢流向局部淋巴结,并不直接进入血液循环,造成局部淋巴结靶向富集.脂质体的淋巴结靶向富集提示胸部恶性肿瘤局部淋巴靶向化疗的可行性.     

Long-term biokinetics and radiation exposure of patients undergoing 14C-glycocholic acid and 14C-xylose breath tests

The (14)C-glycocholic acid and (14)C-xylose breath tests are clinically used for the diagnosis of intestinal diseases, such as bacterial overgrowth in the small intestine. The two tests have in earlier studies been thoroughly evaluated regarding their clinical value, but due to the long physical half-life of (14)C and the limited biokinetic and dosimetric data, which are available for humans, several hospitals have been restrictive in their use. The aim of this study was to investigate the long-term biokinetics and dosimetry of the two (14)C compounds in patients and volunteers, using the highly sensitive accelerator mass spectrometry (AMS) technique. Eighteen (18) subjects were included, 9 for each compound. The (14)C content in samples from exhaled air, urine, and, for some subjects, also feces were analyzed with both liquid scintillation counting (LSC) and AMS. The results from the glycocholic acid study showed that, up to 1 year after the administration, 67%+/-6% (mean+/-standard deviation) of the administered activity was recovered in exhaled air, 2.4%+/-0.4% was found in urine, and 7.6% (1 subject) in feces. In the xylose study, the major part was found in the urine (66%+/-2%). A significant part was exhaled (28%+/-5%), and the result from an initial 72-hour stool collection from 2 of the subjects showed that the excretion by feces was insignificant. The absorbed dose to various organs and tissues and the effective dose were calculated by using biokinetic models, based on a combination of experimental data from the present study and from earlier reports. In the glycocholic acid study, the highest absorbed dose was received by the colon (1.2 mGy/MBq). In the xylose study, the adipose tissue received 0.8 mGy/MBq. The effective dose was estimated to 0.5 (glycocholic acid) and 0.07 mSv/MBq (xylose). Thus, from a radiation protection point of view, we see no need for restrictions in using the two (14)C-labeled radiopharmaceuticals on adults with the activities normally administered (0.07-0.4 MBq).     

Sentinel node biopsy in patients with breast cancer--evaluation of exposure to radiation of medical staff.

AIM: To measure the absorbed doses of radiation to hands of medical staff performing sentinel node biopsy in breast cancer patients. METHODS: The study was conducted in 2004, during sentinel node biopsies in 13 breast cancer patients (T1/T2N0). Sentinel nodes were identified with the use of combined radiotracer/blue dye technique (lymphoscintigraphy--99mTc on albumin carrier, surgery after 24 h; blue dye; intraoperative detection of gamma radiation). Highly sensitive thermoluminescent dosimeters (TLD) made of LiF were used to assess the absorbed doses of radiation during the procedure. During lymphoscintigraphy and during surgical procedure a total of 57 TLDs was placed on different parts of hands of medical staff. RESULTS: Maximal dose recorded during lymphoscintigraphy by TLDs placed on the hands of the physician injecting the radiotracer was 164 microSv. Mean recorded doses were higher for non-dominant hand, especially for distal parts of the index finger, third finger and thumb. During the surgical procedure, TLDs placed on the hands of medical staff recorded much lower doses of radiation than during lymphoscintigraphy. The highest dose was recorded by TLD placed on the pulp of the dominant hand index finger (22 microSv) of the operating surgeon. Mean doses recorded by TLDs placed on the hands of the operating surgeon ranged from 2 to 8 microSv. The absorbed dose of radiation to hands of the scrub nurse was similar to that absorbed to hands of the operating surgeon. CONCLUSION: The maximum recorded dose during sentinel node biopsy in this study was 2200 times smaller than current 1-year dose limit.     

Lymphoscintigraphy and gamma probe tracing in detecting breast cancer lymph node involvement: can they replace axillary lymph node dissection?

BACKGROUND: Axillary lymph node status is the most important pathological determinant of prognosis in early breast cancer. However, axillary lymph node dissection (ALND) performed for pathological assessment is not without costs and morbidity. Recently, radioisotope-guided sentinel node biopsy (SNB) has been proposed as a promising technique for staging breast cancer patients. AIM OF THE STUDY: In this study we report our experience (76 patients) in radioguided sentinel node (SN) biopsy in breast cancer. The study was divided into two phases: the first represents our learning curve, necessary to establish our guidelines for its use in clinical practice, while the second phase was aimed at assessing the feasibility of SN localization using preoperative lymphoscintigraphy and intraoperative gamma probe (GP) detection. METHODS: All patients underwent lymphoscintigraphy (LS) up to two hours after tracer delivery (99mTc-micro-nanocolloid, four i.d. injections of 200 microCi/200 miccroL around the primary lesion) 24 hours before surgery and GP tracing during surgery. Subsequently ALND was performed for pathological assessment. RESULTS: SNs were identified in 73/76 patients using LS and in 72/76 using GP. In one case the SN was detected by GP alone while in two cases GP was not able to locate the SN although it had been identified by means of LS. Thirty-three of these 73 patients had axillary node involvement. In 31/33 cases the SN was the only positive node. No positive nodes were found in the remaining 40 ALNDs where SNs were identified. Thus, according to our experience 40/73 ALNDs could have been avoided. SNB seems to be a very interesting technique but further experience in lymph node radioisotope tracing is needed.