You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Frequency and intensity of pain related to thyroid nodule fine needle aspiration cytology. Background: Quality of life is an important issue in endocrine tumors because of the high prevalence of benign tumors and the indolent course of most malignant tumors. Objective: To evaluate the frequency and the intensity of pain and anxiety in patients undergoing thyroid nodule fine needle aspiration cytology (FNAC), and to identify factors associated with pain. Method: Single center prospective study in the setting of a one-stop outpatient diagnostic clinic for thyroid nodules. Pain was evaluated using a 100-mm visual analogue scale (VAS) immediately following (VAS1) and 30 minutes after (VAS2) FNAC and was considered significant if ≥30. Anxiety symptoms were assessed prior to FNAC using a self-report measure questionnaire: the state form of Spielberger State-Trait Anxiety Inventory (STAI, form Y-A). FNAC was performed with a 25-Gauge needle and a moderate aspiration and two passes for each nodule. Results: 218 consecutive patients (163 females, 55 males; mean age 53 years, range 12-84) undergoing FNAC of 1 to 3 nodules were included. VAS1 was ≥30 in 24% of the patients and VAS2 was 30 in 13% of the patients. Independent significant factors correlated to a VAS1 30 were age under 25 and the number of nodules being biopsied. Independent significant factors correlated to a VAS2 30 were VAS1 30 and female gender. No correlation was found between pain and nodule size or nodule depth, nor the duration of application of the Eutectic Mixture of Local Anesthetics (EMLA patch) prior to FNAC. The mean STAI score for anxiety was 37  12. The average STAI score was significantly higher in women (39) than in men (33) (p=0.01). There was no significant correlation between STAI score and age under 25, previous FNAC, number of nodules biopsied or acetaminophen administration, but the STAI score was significantly correlated to VAS1 and VAS2 Conclusions: FNAC-related pain is frequent and correlates with the number of nodules biopsied, age under 25, female gender and anxiety.
{"Chemical": []}