ABSTRACT
Objective[s]: radiation therapy for breast cancer can induce myocardial capillary injury and increase cardiovascular morbidity and mortality. A prospective cohort was conducted to study the prevalence of myocardial perfusion abnormalities following radiation therapy of left-sided breast cancer patients as compared to those with right-sided cancer
Methods: to minimize potential confounding factors, only those patients with low 10-year risk of coronary artery disease [based on Framingham risk scoring] were included. All patients were initially treated by modified radical mastectomy and then were managed by postoperative 3D Conformal Radiation Therapy [CRT] to the surgical bed with an additional 1-cm margin, delivered by 46-50 Gy [in 2 Gy daily fractions] over a 5-week course. The same dose-adjusted chemotherapy regimen [including anthracyclines, cyclophosphamide and taxol] was given to all patients. Six months after radiation therapy, all patients underwent cardiac SPECT for the evaluation of myocardial perfusion
Results: a total of 71 patients with a mean age of 45.3 +/- 7.2 years [35 patients with leftsided breast cancer [exposed] and 36 patients with right-sided cancer [controls]] were enrolled. Dose-volume histogram [DVH] [showing the percentage of the heart exposed to >50% of radiation] was significantly higher in patients with left-sided breast cancer. Visual interpretation detected perfusion abnormalities in 42.9% of cases and 16.7% of controls [P=0.02, Odds ratio=1.46]. In semiquantitative segmental analysis, only apical [28.6% versus 8.3%, P=0.03] and anterolateral [17.1% versus 2.8%, P=0.049] walls showed significantly reduced myocardial perfusion in the exposed group. Summed Stress Score [SSS] of>3 was observed in twelve cases [34.3%], while in five of the controls [13.9%],[Odds ratio=1.3]. There was no significant difference between the groups regarding left ventricular ejection fraction
Conclusion: the risk of radiation induced myocardial perfusion abnormality in patients treated with CRT on the left hemi thorax is not low. It is reasonable to minimize the volume of the heart being in the field of radiation employing didactic radiation planning techniques. Also it is advisable to screen these patients with MPI-SPECT, even if they are clinically asymptomatic, as early diagnosis and treatment of silent ischemia may change the outcome
ABSTRACT
We intended to assess the accuracy of re-expressed Modification of Diet for Renal Disease [MDRD] and Cockcroft-Gault [CG] equations to estimate glomerular filtration rate [GFR] in chronic kidney disease in two different etiologies of acute renal failure [ARF]: acute tubular necrosis [ATN] and acute glomerulonephritis [AGN]. Patients admitted for ARF or the patients complicated with ARF during the course of their hospitalization were enrolled to the study [n=21; 14 females and 7 males; 11 ATN and 12 AGN]. When the plasma creatinine reached a steady state [DPSM] using [99m]Tc-DTPA. GFR was also estimated by MDRD [GFRMDRD] and CG [GFRCG] equations. The patients aged 44.8 +/- 19.5 years and weighted 67.8 +/- 10.7kg. GFRDPSM [32.9 +/- 14.7 ml/min] was statistically different from the GFRMDRD [11.6 +/- 8.2 ml/min; pCG was lower than GFRDPSM in patients with either ATN [16.5 +/- 12.5ml/min and pDPSM and GFRMDRD [r=0.34; p=0.13] but GFRDPSM and GFRCG values were correlated [r=0.48; p=0.03]. Out of subjects with GFRDPSM >30, 92.3% had GFRMDRDCG Our results indicate that MDRD and CG equations were substantially inaccurate in patients with ARF. More precise methods of GFR evaluation is recommended in these patients
ABSTRACT
The main purpose of this study was to compare transient ischemic dilation [TID] ratios in SPECT-low dose CT and SPECT Myocardial Perfusion Imaging [MPI] by application of different quantitative programs and quantify the possible shift in the upper normal limits of TID ratio in the SPECT-CT MPI. 149 Patients with low pre-test probability for coronary artery disease [CAD], based upon Diamond and Forrester method entered the study. Each patient underwent both attenuation correction [AC] SPECT-CT MPI and non attenuation correction [NAC] SPECT MPI [two day Tc-99m sestamibi stress-rest protocol]. Normalcy rates were also calculated and compared. The comparison was based on both visual interpretation and quantitative analysis. In the low pre-test probability group visual interpretations lead to a statistically significant improvement in normalcy rate in the SPECT-CT acquisition compared to the SPECT MPI. Regardless of the stress type and software programs used, no significant difference was noted in the upper normal limits of the TID ratios between the AC and NAC acquisitions. The study showed superiority of SPECT-CT MPI to SPECT MPI in terms of normalcy rate. We also propose new upper normal limits of TID ratios for different sets of acquisition-gender-stress modality-software programs
ABSTRACT
The aim of this study was to evaluate the effect of successful kidney transplantation [KT] on myocardial perfusion and left ventricular function by both qualitative [visual] interpretation and semiquantitative parameters, using myocardial perfusion scintigraphy with gated-single photon emission computed tomography [gated-SPECT] in patients suffering from end-stage renal disease. From a total of 38 patients who were candidates of KT, twenty-six patients [16 female, 10 male, mean age: 47.5 yr, range: 24-64 yr] who had successful KT were included. Myocardial perfusion scintigraphy was performed by Gated Single Photon Emission Computed Tomography [Gated-SPECT] method, before and after surgery [mean: 24 months]. Perfusion and function status was evaluated by qualitative and semiquantitative parameters. Our data showed qualitative evidence of perfusion and functional abnormality in pre-transplant scans as follows: Abnormal perfusion in left anterior descending [LAD], left circumflex [LCX] and right coronary artery [RCA] territories in 42.5%, 53.8% and 65.4% of cases, respectively; dilation in 57.7% and inhomogenity of uptake in 53.8% of cases. However no statistically significant change was noted after transplantation, i.e. p value for all semiquantitative values including summed stress score [SSS], summed rest score [SRS] and summed difference score [SDS], summed motion score [SMS], summed thickening score [STS], ejection fraction [EF], end diastolic volume [EDV], end systolic volume [ESV], and stroke volume [SV] was greater than 0.05. Renal transplantation may not have considerable long term effect on myocardial perfusion and function in patients with chronic renal failure. This could be due to either non-reversible myocardial changes or continuing effect of degrading factors on the myocardium
ABSTRACT
Monte Carlo [MC] is the most common method for simulating virtual SPECT projections. It is useful for optimizing procedures, evaluating correction algorithms and more recently image reconstruction as a forward projector in iterative algorithms; however, the main drawback of MC is its long run time. We introduced a model based method considering the effect of body attenuation and imaging system response for fast creation of noise free SPECT projections. Collimator detector response [CDR] was modeled by layer by layer blurring of activity phantom using suitable Gaussian functions. Using the attenuation phantom, in each angle, attenuation factor [AF] was calculated for each voxel. This calculated AF is the weight for the emission voxel and states the detection probability of photons that are emitted from that voxel. Finally weighted ray sum of the blurred phantom was driven to create a projection. For the next projection, our phantom was rotated and the procedure was repeated until all projections were acquired. Root Mean Square error [RMS] between all 60 modelled projection and real MC simulated projections was decreased from 0.58 +/- 0.15 using simple Radon to 0.19 +/- 0.03 using our suggested model. This value was 0.56 +/- 0.16 using blurred Radon without attenuation modelling, and 0.21 +/- 0.03 using attenuated Radon without CDR modelling. Our suggested model that considers the effect of both attenuation and CDR simultaneously results in more accurate analytical projections compared with conventional Radon model. Creation of 60 primary SPECT projections in less than one minute may make this method as a proper alternative for MC simulation. This model can be used as a forward projector during iterative image reconstruction for correction of CDR and attenuation that is necessary for quantitative SPECT
ABSTRACT
Radioiodine therapy is the safest, simplest, least expensive and most effective method for treatment of hyperthyroidism. The method employed in this research was a systematic bibliographic review, in which only valid studies or the clinically detailed enough open-labeled studies using validated scales were used. Iodine-131 [I-131] acts by the destructive effect of short-range beta radiation on thyroid cells. Indications for radioiodine therapy include toxic nodules [in which I-131 is the first choice of treatment], recurrent hyperthyroidism after antithyroid treatment or surgery, intolerance to antithyroid therapy due to side-effects and patient preference. Due to difficulties in previous methods for dose determination, fixed dose method of I-131 is now considered the best practical method for radioiodine therapy in primary hyperthyroidism. Absolute contraindications for radioiodine treatment are pregnancy and lactation. In pediatric patients, radioiodine therapy can be used, but is mainly considered in recurrent toxic goiter and when antithyroid medication is ineffective. There is no clear evidence indicative of carcinogenic or teratogenic effect of this agent
Subject(s)
Humans , Iodine Radioisotopes/adverse effects , Iodine Radioisotopes/administration & dosage , Iodine Radioisotopes , Hyperthyroidism/diagnosisABSTRACT
Ubiquicidin [UBI] 29-41 is a synthetic antimicrobial peptide that binds with the microbial cell membrane at the location of infection. This study was conducted to evaluate its probable efficacy as an infection-imaging agent with potential to differentiate bacterial infection from sterile inflammation in humans. Fifteen diabetic foot patients [10 males and 5 females] with suspected bacterial infection, prior to starting antibiotic treatment, were selected for this study. First a routine three phase bone scan and later a [99m]Tc-UBI scan was performed for all the patients. 555-740 MBq of [99m]Tc-UBI was injected intravenously. A 10 minute dynamic study was followed by spot views of the suspected region of infection and corresponding normal areas [liver and kidneys] at 60 and 120 min. Whole-body anterior and posterior images were also acquired. To interpret the studies as positive or negative, visual score [0 -3] was used, with scores of 0 [minimal or no uptake; equivalent to soft tissue] and 1 [mild; less uptake than in liver] being considered negative and scores of 2 [moderate; uptake equal to or greater than that in liver] and 3 [intense uptake equal to or greater than that in kidneys] being considered positive. Of 15 studies performed with [99m]Tc-UBI, all had positive bacterial cultures. The result of bone scan was positive for osteomyelitis in 12 patients [80%]. [99m]Tc-UBI Scintigraphy was positive in 6 patients, but negative in nine. The sensitivity of [99m]Tc-UBI for detection of infection was therefore 40%. From 12 patients who had positive bone scans, only 6 had a positive [99m]Tc-UBI [50%] indicating the sensitivity of 50% for [99m]Tc-UBI in osteomyelitis cases. 99mTc-UBI was not positive in any patient who had evidence of soft tissue infection in the bone scan. Although [99m]Tc-UBI 29-41 was well tolerated by all the patients without any side effects, considering low sensitivity of this agent, this radiopharmaceutical is not of great value for diabetic foot infection diagnosis
ABSTRACT
A 57-year-old male with history of prostatectomy, cyctectomy, cecal urinary diversion for invasive prostate cancer and with a recent rise in PSA level, was referred for bone scintigraphy to rule out osseous metastatic disease. An interesting finding was abnormal tracer accumulation throughout the large bowel, which was proved to be due to urinary diversion