Radiation safety survey on a flattening filter-free medical accelerator

Dose rates at several locations outside a treatment room were measured for 6 and 18 MV photon beams from a Varian Clinac 21EX accelerator operated with and without a flattening filter. Also, dose rates in the treatment room due to activation were measured at 18 MV. An analysis of the measured data is presented. The results suggest that substantial reduction in doses outside the treatment room and lower activation can be achieved with a flattening-filter free accelerator.

The evidence base of complementary and alternative therapies in depression

BACKGROUND

Depression is one of the leading indications for using Complementary and Alternative Medicine (CAM). This paper reviews the evidence of efficacy of different types of CAM in depression with the aim of identifying the highest level of evidence.

METHODS

We conducted literature searches restricted to the English language for studies on CAM as monotherapy in depression. All papers were reviewed by two researchers and the evidence was ranked according to a widely referenced hierarchy of evidence.

RESULTS

19 papers formed the final review. We found Grade 1 evidence on the use of St. John's wort, Tryptophan/5-Hydroxytryptophan, S-adenosyl methionine, Folate, Inositol, Acupuncture and Exercise in Depressive disorders, none of which was conclusively positive. We found RCTs at the Grade 2 level on the use of Saffron (Herbal medicine), Complex Homoeopathy and Relaxation training in Depressive disorders, all of which showed inconclusive results. Other RCTs yielded unequivocally negative results. Studies below this level yielded inconclusive or negative results.

LIMITATIONS

Searches were restricted to the English language. Our list of CAM approaches may not have been comprehensive. We excluded studies on the use of CAM as an adjunctive treatment and this review aimed to identify only the highest level of evidence.

CONCLUSIONS

None of the CAM studies show evidence of efficacy in depression according to the hierarchy of evidence. The RCT model and the principles underlying many types of CAM are dissonant, making its application in the evaluation of those types of CAM difficult. The hierarchy of evidence we used has limited utility in grading trials of CAM.

Structural, spectral, linear and nonlinear optical properties of new nonlinear optical L-histidinium trichloroacetate crystals

Single crystals of a new histidinium salt: L-histidinium trichloroacetate {abbreviated as LHTCA; [(C(3)N(2)H(4))CH(2)CH(NH(3))(CO(2))](+)CCl(3)COO(-)} were grown by slow evaporation of an aqueous solution at room temperature. The compound crystallizes in a non-centrosymmetric space group P2(1) of monoclinic system with cell parameters a=5.4505(18) A, b=25.769(8) A, c=9.210(2) A and beta=99.98(2) degrees. The vibrational structure of the compound confirms the presence of various functional groups in the molecule. The UV-vis-NIR spectrum shows a good transparency in the whole of the region from ultraviolet to near IR. The Kurtz powder SHG measurement confirms the frequency doubling of the crystal. Thermal behaviour of the crystals has been investigated by DSC analysis. These preliminary results suggest that LHTCA crystal can act as a potential and promising candidate for frequency doubling applications even from the near UV region to the near IR.