Role of various screening techniques in detecting preinvasive lesions of the cervix among symptomatic women and women having unhealthy cervix.

INTRODUCTION: Cervical cancer which is preventable, occurs due to humanpapiloma virus infection and results in a preinvasive condition called cervical intraepithelial neoplasm (CIN) before the development of cancer. Majority of the patients with CIN or early stage of cervical cancer present with symptoms such as abnormal vaginal discharge or bleeding, and unhealthy looking cervix. Selectively screening these symptomatic patients, can detect more number of positive cases and also most effective screening technique for these selective patients can be advocated. MATERIALS AND METHODS: All married women between 21 and 65 years attending gynecology outpatient department of a tertiary care health center in Central India and having unhealthy cervix or abnormal vaginal discharge were included. All women were subjected to Pap smear, visual inspection under acetic acid (VIA), visual inspection under Lugol's iodine (VILI) and colposcopy. Biopsy was taken in all cases. Diagnostic value of each screening method was determined in terms of sensitivity, specificity, positive predictive value and negative predictive value. RESULTS: Out of 352 patients, around 20% of them were found to have abnormal cytology. The sensitivity and specificity of Pap smear was found to be 34% and 94%. But colposcopy has high sensitivity and low specificity, i.e., 99% and 31%, respectively. On the other hand the sensitivity and specificity of VIA and VILI are comparable i.e., 65% and 45% and 64% and 48% respectively. Pap smear shows high positive predictive value among all, i.e., 85% and colposcopy shows 58% for the same. CONCLUSION: Pap smear carries low sensitivity but high positive predictive value. As compared to Pap smear, VIA and VILI are more sensitive and are of low cost. Colposcopy can be considered as a preferred method of screening due to its extremely high sensitivity.

Development and characterization of an all-in-one gamma probe with auto-peak detection for sentinel lymph node biopsy based on NEMA NU3-2004 standard.

BACKGROUND: A gamma probe is a handheld device used for intraoperative interventions following interstitial injection of a radiotracer to locate regional lymph nodes through the external detection of radiation. This work reports on the design and performance evaluation of a novel fully integrated gamma probe (GammaPen), recently developed by our group. MATERIALS AND METHODS: GammaPen is an all-in-one pocket gamma probe with low weight and adequate dimensions, consisting of a detector, a control unit and output all together. The detector module consists of a cylindrical Thallium-activated Cesium Iodide [CsI (Tl)] crystal optically coupled to a Silicon photomultiplier (SiPM), shielded using Tungsten housing on side and back faces. The electronics of the probe consists of two small boards to handle signal processing and analog peak detection tasks. A number of parameters, including probe sensitivity in air/water, spatial resolution in air/water, angular resolution in air/water, and side and back shielding effectiveness, were measured to evaluate the performance of the probe based on NEMA NU3-2004 standards. RESULTS: The sensitivity of the probe in air at distances of 10, 30, and 50 mm is 18784, 3500, and 1575 cps/MBq. The sensitivity in scattering medium was also measured at distances of 10, 30, and 50 mm as 17,680, 3050, and 1104 cps/MBq. The spatial and angular resolutions in scattering medium were 47 mm and 87 degree at 30 mm distance from the probe, while they were 40 mm and 77 degree in air. The detector shielding effectiveness and leakage sensitivity are 99.91% and 0.09%, respectively. CONCLUSION: The performance characterization showed that GammaPen can be used effectively for sentinel lymph node localization. The probe was successfully used in several surgical interventions by an experienced surgeon confirming its suitability in a clinical setting.

Matrix elimination ion chromatography method for the determination of trace levels of anionic impurities in high purity cesium iodide.

In the present study an ion chromatographic method based on matrix elimination has been developed for the determination of anionic impurities in high purity cesium iodide crystals. The presence of impurities has a detrimental effect on the characteristics of detectors based on cesium iodide crystals. In particular, oxygen-containing anions inhibit the resolving power of scintillators and decrease the optical absorption. The quantitative determination of anions (fluoride, chloride, bromide, nitrate, phosphate, and sulphate) simultaneously in the high-purity cesium iodide crystals has not been carried out before. The large concentration of iodide poses a challenge in the determination of anions (especially phosphate and sulphate); hence, matrix elimination is accomplished by adopting a sample pretreatment technique. The method is validated for linearity, accuracy, and precision. The limit of detection for different anions is in the range of 0.3-3 µg/g, and the relative standard deviation is in the range of 4-6% for the overall method.

[Photometric analysis of sodium and cesium iodides in the air of the work area]. / Fotometricheskoe opredelenie iodidov natriia i tseziia v vozdukhe rabochei zony.

The contributors propose a photometric technique for detecting sodium and caesium iodides in the working zone air. The technique is based on the oxidation of I-ions with bromine water, interacting of the educed iodine and redundant potassium iodide with concomitant formation of complex I3- ions, followed by 350-365 mm photometric measurements of the product. Air sample taking is performed by condensating on AFA--VP filtres. The lower limit of I-ions content measurements is 5 micrograms. The measurement range for sodium and caesium iodides is 0.2-50 mg/m3. Data is provided for the reproduction of the technique which can be used both in special laboratory and industrial conditions.