Revolutionary impact of PET and PET-CT on the day-to-day practice of medicine and its great potential for improving future health care

In this communication, we present an overview of the impact and advantages of PET and PET-CT fusion imaging in the practice of medicine. We also discuss the evolution of this promising molecular imaging technique since its inception and the future prospects of the combined structure-function approach. Superior contrast resolution, accurate quantification and above all optimal image quality aid in improved diagnosis of many serious disorders including cancer. We speculate that this powerful imaging approach will almost completely replace most other conventional methods in the future. Currently, 18[F]-fluorode- -oxyglucose (FDG) is the main radiopharmaceutical employed for PET studies around the globe. With the availability of high quality PET images on a routine basis in most centres around the world and the likelihood that several other useful PET tracers will be approved in the near future for routine clinical applications, this technique will likely become essential in almost any medical disorder

Estimation of sacroiliac joint index in normal subjects of various age groups: comparative evaluation of four different methods of quantification in skeletal scintigraphy

BACKGROUND: To estimate and compare the sacroiliac joint(SIJ) index in skeletal scintigraphy by four different methodsof quantification employed in normal subjects of different agegroups.MATERIAL AND METHODS: The whole-body skeletal survey of100 subjects, who underwent skeletal scintigraphy three hoursafter injection of 99mTc-Methylene Diphosphonate (MDP), wereselected for this analysis. The patients having previous historyof low back pain, joint pain or any benign bone joint disorders(e.g. ankylosing spondylitis, metabolic bone disease, andosteoarthritis), documented bone lesions or tumors within thepelvis region were excluded from the study. All subjects hadnormal posterior pelvis view on visual assessment in the respectivestudy. Sacroiliac joint index was calculated by quantitative sacroiliac scintigraphy. In each subject, four different methods of quantification were carried out: 1. irregular region of interest(ROI) method, 2. rectangular ROI method, 3. profile peak counts(PPC) method and 4. profile integrated counts (PIC) methodand applied to calculate SIJ index. SIJ indices for left and rightsacroiliac joints were calculated by dividing the count for eachjoint by the count for the sacrum. Results obtained by the fourmethods were compared statistically.RESULTS: The overall SIJ index was found to range from 1.06to 1.36 in the study population of 100 subjects encompassing allage groups. There was no significant difference in the estimatedSIJ index within each age group obtained by the four differentmethods employed in this study. The values of SIJ index wereas follows: in patients aged 2–20 years — they ranged from 1.22to 1.36; in patients aged 21–40 years — from 1.07 to 1.19; forpatients aged 41–60 years — from 1.08 to 1.19 and in patientsaged 61 years and older, SIJ values were slightly lower than inother groups and ranged from 1.06 to 1.13.CONCLUSION: Methods of selecting a region of interest haveno significant effect on the calculation of SIJ index and in healthysubjects its values range between 1.06 and 1.36, depending onthe age of the subject. The maximum value was observed inpatients aged 2–20 years and minimum values were noted inpatients aged 61 and older

Almost Empty Monochromatic Triangles in Planar Point Sets

For positive integers c, s ≥ 1, let M3 (c, s) be the least integer such that any set of at least M3 (c, s) points in the plane, no three on a line and colored with c colors, contains a monochromatic triangle with at most s interior points. The case s = 0 , which corresponds to empty monochromatic triangles, has been studied extensively over the last few years. In particular, it is known that M3 (1, 0) = 3, M3 (2, 0) = 9, and M3 (c, 0) = ∞, for c ≥ 3. In this paper we extend these results when c ≥ 2 and s ≥ 1. We prove that the least integer λ3 (c) such that M3 (c, λ3 (c)) \u3c ∞ satisfies: ⌊(c-1)/2⌋ ≤ λ3 (c) ≤ c - 2, where c ≥ 2. Moreover, the exact values of M3 (c, s) are determined for small values of c and s. We also conjecture that λ3 (4) = 1, and verify it for sufficiently large Horton sets