The bone scan is the accepted initial imaging modality for skeletal metastases. Some patients use chemotherapy in the initial stages before and after surgery for breast cancer patients according to the international protocol; this study aimed to evaluate the time elapsed between the bone scan and chemotherapy dose that effected on renal function using GFR measurement. It is a retrospective study designed and conducted in the Nuclear Medicine Department, King Abdulla medical city (KSA) which included 150 female breast cancer patients with age ranged between 25-75 years, and their weight ranged 40-120 kg. All patients were diagnosed with breast cancer according to the histopathology report and were received chemotherapy treatment except group control. The results of this study revealed that the most common drugs used for adjuvant and nan adjuvant is (cisplatin combination ) chemotherapy, the effects of this types of drugs on GFR is with significant correlation of - 0.07 when the GFR after chemotherapy treatment id measured compare to the GFR values of the same patients before the chemotherapy treatment was given , also the result revealed that all counts from the bone target in the bone scan was decreased after treatment in all groups and there are a direct linear relationship between the acquired counts and the elapse time after chemotherapy, the coefficient of this relationship indicates that the researcher applied the specific threshold segmentation in order to increase the image quality by decreasing the values of the counts per background pixel and increased the value of counts per bone region pixel and increasing the ratio between the background counts to the bone region counts per pixel, the result showed a strong significant correlation of 0.733 between the applied threshold significant and the ratio of bone counts to the background counts, the researcher set a values of recommended threshold segmentation which should be applied for bone scan image to the patients treated with chemotherapy, these set of segmentation values depended on the time intervals between the bone scan and the chemotherapy treatments in order to increase the image quality to be quite diagnosable, the threshold segmentation should be increased by a factors of 54.4%, 130%, 218.2% and 278.2% form the threshold segmentation of the normal control groups of patients for bone scan after 4,3,2 and 1 weeks from chemotherapy treatments respectively, this study concluded that the suitable time for bone scan posts chemotherapy is four weeks unless a care of image processing are taken into consideration in term of threshold values in order to increase the bone target counts Vs. the background non target counts.
