Experimental response function of a 3 in×3 in NaI(Tl) detector by inverse matrix method and effective atomic number of composite materials by gamma backscattering technique.

Response function of a widely used 3in×3in NaI(Tl) detector is constructed to correct the observed pulse height distribution. A 10×10 inverse matrix is constructed using 7 mono-energetic gamma sources ((57)Co, (203)Hg, (133)Ba, (22)Na, (137)Cs, (54)Mn and (65)Zn) which are evenly spaced in energy scale to unscramble the observed pulse height distribution. Bin widths (E)(1/2) of 0.01 (MeV)(1/2) are used to construct the matrix. Backscattered photons for an angle of 110° are obtained from a well-collimated 0.2146GBq (5.8mCi) (137)Cs gamma source for carbon, aluminium, iron, copper, granite and Portland cement. For each observed spectrum, single scattered spectrum is constructed analytically using detector parameters like FWHM, photo-peak efficiency and peak counts. Response corrected multiple scattered photons are extracted from the observed pulse height distribution by dividing the spectrum into a 10 ×1 matrix. Saturation thicknesses of carbon, aluminium, iron, copper, granite and Portland cement are found out. Variation of multiple scattered photons as a function of target thickness are simulated using MCNP code. A relationship between experimental and simulated saturation thicknesses of carbon, aluminium, iron and copper is obtained as a function of atomic number. Using this relation, effective atomic numbers of granite and Portland cement are obtained from interpolation method. Effective atomic numbers of granite and Portland cement are also obtained by theoretical equation using their elemental composition and comparing with the experimental and simulated results.

Relapse of leprosy presenting as nodular lymph node swelling.

Lymphadenopathy is known to be associated with lepromatous leprosy and has also been observed as a feature of type-2 lepra reaction. However, nodular lymph node enlargement is not commonly reported in leprosy patients or as a feature of relapse. We herewith are presenting a case of bacteriological relapse in a patient of lepromatous leprosy treated 22 years before till smear negativity with WHO multidrug therapy (MDT) multibacillary type (MB). She presented with prominent nodular swelling of the cervical group of lymph nodes along with generalized lymphadenopathy, which was mistakenly treated as tubercular lymphadenopathy. A diagnosis of late bacteriological relapse of lepromatous leprosy presenting with prominent lymphadenopathy and ENL was made after relevant investigations. The patient was started on treatment with WHO MDT MB (daily dapsone and clofazimine and monthly rifampicin) and thalidomide (200 mg/day). Nerve pain regressed within 2 weeks of therapy. The lymph nodal swelling regressed within 3 months of starting treatment.

The significance of facial patches and type I reaction for the development of facial nerve damage in leprosy. A retrospective study among 1226 paucibacillary leprosy patients.

Charts of 1226 paucibacillary leprosy patients, registered between 1982 and 1987 were reviewed for recent facial nerve damage, facial patches and the presence of Type I reaction. Twenty-six (2.1%) patients with recent lagophthalmos were identified. In a great majority (85%) patients with recent lagophthalmos showed significant patches over the malar region or around the eye, at the same side as the nerve damage together with clinical signs of Type I reaction. This combination of significant patches in certain locations and Type I reaction seems to be a pre-condition for facial nerve damage. The clinical implication is that a small group of patients may be identified, who are at risk of facial nerve damage. By examining these patients more carefully it will be possible to detect nerve damage early and to prevent permanent damage of the facial nerve by timely treatment with an appropriate steroid regimen.

Treatment of recent facial nerve damage with lagophthalmos, using a semistandardized steroid regimen.

Twenty-seven patients with borderline leprosy and facial nerve damage of less than or equal to 6 months duration (36 eyes) were treated with a semistandardized regimen of steroids (the average starting dose was 25-30 mg, duration 5-6 months) on an outpatient basis. Red and raised reactive patches were usually present in the upper malar area or around the eye(s) in patients with recent lagophthalmos. The lid gap was measured in millimetres during gentle and strong closure. After completion of the steroid course 75% of the eyes had complete closure or only a slight gap of less than or equal to 2 mm on gentle closure. Steroids were found to be beneficial and safe, in the dosage that we prescribed.