A randomized comparative study of levonorgestrel-releasing intrauterine device (LNG-IUD) and Norplant-2 implants was carried out in 200 women for 36 months. Three thousand one hundred woman-months of use were observed with each device. Only one pregnancy occurred in users of LNG-IUD at the 12th month of use. The change in bleeding pattern was the most frequent reason for discontinuation. The discontinuation rate for irregular bleeding with Norplant-2 was 17.3 and 26.8 at 24 and 36 months, respectively, as compared to 3.3 with LNG-IUD at both 24 and 36 months. The differences were statistically significant. Removal for amenorrhea and pain only occurred in acceptors of LNG-IUD. About 20-40% of women using Norplant-2 had prolonged bleeding through 36 months. The percentage of amenorrhea in LNG-IUD was the highest (29.3%) at the end of two years of use. More than 97% of subjects reported satisfaction with the methods used by themselves.
for the prostate and lung tumors. Niemierko model produced marginally different (< 4%) TCPs than that from the Poisson model for the DVH whose minimal dose are less than 20 Gy than the mean dose; however, for DVHs with differences between minimal dose and mean dose greater than 30 Gy, linearly depending on the dose differences, Niemierko-calculated TCPs were substantially smaller than those from Poisson model. For DVHs with Poisson model-calculated TCPs less than 40%, the "Marsden" model produced TCPs < 1%, but linearly increasing from 0 to100% with Poisson model TCPs for the other DVHs. Conclusion: IMRT for prostate and H&N cancers showed higher TCPs than lung cancer treatment calculated using the three TCP models. Poisson and Niemierko model-calculated TCPs were significantly different when the minimal dose was >30 Gy less than the median dose in a DVH. "Marsden" Model showed much sharper dose response than the Poisson and Niemierko models. The radiobiological models should be assessed when applying in IMRT treatment plan and evaluation of prescription models (D100 or D95).
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