Investigation of Formalin-Fixed Tissue Optical Characteristics in the Range of 200–500 GHz Using Pulsed Terahertz Reflection Spectroscopy to Differentiate Oral Malignant, Benign, and Cyst

Table 1

Various noninvasive techniques for diagnosing oral tissues.

S.No	Techniques	Specimen	Sensitivity (%)	Advantages	Dis-advantages	Cost (INR)
1	Autofluorescence spectroscopy [13]	Oral tissue	91.1	It is a noninvasive technique and patient-friendly	Nonspecific	500–1000
2	Diffuse reflectance spectroscopy [14]	Oral tissue	94	Low cost, it gives quantitative results with good sensitivity & specificity	The result surrounds the overlapping of bands	500–2000
3	Elastic scattering spectroscopy biopsy [15]	Oral tissue	82	No secondary procedures	Time-consuming
4	Histopathological examination [16]	Oral tissue	NA	The study of large portions of tissues minimal or risk	Chances of human error broader in scope; Cell kinds are difficult to identify.	800–6400
5	Immunohistochemistry [17]	Oral tissue	NA	Used widely	Chances of human error	1500–3500
6	Incisional biopsy [18]	Oral tissue	NA	a little piece of tissue is used. Performed in suspected instances of cancer and precancer.	Increased risk of metastasis of malignant lesions.	1000–2000
7	Laser capture microdissection [19]	Oral tissue	NA	Cell separation is precise and fast	Expensive sample contamination. High level of expertise required	6000
8	Mass spectroscopy [20]	Oral tissue	NA	Molecular profiling of tissues	Expensive instrumentation
9	Optical coherence tomography [21]	Oral mucosa	91	Noninvasive easy-to-use	Hyperkeratosis has a negative impact on image quality.	1000–2500
10	Raman spectroscopy [22]	Oral tissue	90	Minimal sample preparation nondestructive noninvasive	Bands overlap, making it difficult to distinguish specific components.	1500
11	Vital staining techniques [23]	Oral tissue	91	Noninvasive	A significant number of false positive instances are evaluated.	500