Ethics statement
The present study was approved by the ethics committee of Shanxi Bethune Hospital. All patients provided written informed consent for their clinical information to be reviewed and the study was carried out in accordance with approved guidelines.
1.1 Research subjects and grouping
(1) Patients: Between June 2018 and March 2021, 31 cases of thyroid cancer with nasolacrimal duct obstruction were selected during follow-up of 131I therapy in the Department of Nuclear Medicine, Shanxi Bethune Hospital. The male: female ratio was 1:14.5 and mean age of onset was 54 ± 13 years (range: 17-71 years). 61 patients with thyroid cancer and without nasolacrimal duct obstruction were also enrolled and had mean age of onset of 46 ± 11 years (range 16-78 years). Those with epiphora and those without were subdivided into those ≤ 55 years and those > 55 years old. Groupings were also subdivided by dosage of iodine into those receiving ≤ 5.55GBq and those receiving > 5.5GBq. Following 131I therapy, whole-body imaging was performed to evaluate the presence of metastases and nasal uptake concentrations.
1) Exclusion criteria were as follows: allergy, nasal cavity/ sinus problems or facial trauma. Patients with contact lenses, autoimmune diseases, medications that may cause tear discharge syndrome and all eye diseases were also excluded from the study.
2) Nasolacrimal duct obstruction was diagnosed by an ophthalmologist according to the following criteria: lacrimal duct irrigation indicating complete obstruction of the lacrimal passage, all flushing fluid flowed back from upper/lower lacrimal dots, the obstruction site was located in the nasolacrimal duct, with or without sticky or purulent secretion. Other secondary factors were excluded.
1.2 Method
(1) Anti thyroglobulin antibodies (TGAb) were determined by electrochemiluminescence immunoassay (Roche) with a detection range of 10-4000 Ku / L. The upper limit of TGAb normal range is 115 Ku / L. If the upper limit of the normal range was exceeded, TGAb was positive.
(2) After therapy, whole body 131I(131I-WBS) imaging was performed:
1) All patients completed the whole body anteroposterior plane imaging (RX- WBS) and neck-chest SPECT / CT fusion imaging on the third day after oral ingestion of 131I(Atomic HighTech Co. Ltd., Guangzhou, China). After the 131I-WBS, a nuclear medicine specialist evaluated the images on the workstation immediately to decide whether to add other parts of tomographic fusion imaging on the basis of SPECT / CT fusion imaging of neck and chest.
2)131I-WBS and SPECT/CT acquisition: Discovery NM / CT 670 dual probe SPECT / CT instrument (GE , USA). The probe is equipped with high energy and low resolution parallel hole collimator. The photopeak was 364kev, the window width was 20%, the matrix was set at 256x1024 and the imaging speed was 5cm / min.
3) SPECT / CT tomographic fusion imaging: the acquisition parameters were as follows: tube voltage 140 kV, tube current 200 mA, slice thickness 375mm and matrices 512×512.JET stream workstation (GE Medical Systems) was applied to obtain the SPECT/CT fusion images .
(3) Image analysis: radionuclide images (WBS and SPECT/CT) were independently evaluated by 2 experienced nuclear medicine physicians blinded to patients’ clinical condition with interpretation in consensus, using diagnostic software (Compass viewer H 4.0, Medivoly Technology Co. Ltd., Shanghai, China).
1.3 Statistical analysis
Clinical data and imaging features were examined. Normally distributed quantitative data is presented as X ± s with count data being described by constituent ratio. Chi square test was used to analyze count data. Logistic regression model was used to analyze related factors. Variables with statistical significance from univariate analysis were included in multivariate regression analysis. All data was analyzed by SPSS 23.0 for windows (SPSS Chicago, IL, USA) software with a p value<0.05 being considered statistically significant.