ABSTRACT
To measure radiation exposures rate in low-risk patients having stress-only and stress-rest myocardial perfusion imaging. This was a prospective study conducted from January 2012 till November 2012 upon patients with low pre-test probability for coronary artery disease [CAD]. A stress MPI [stress-only if MPI is normal and no resting study] followed by a resting MPI study [same day] if stress study was positive or equivocal. Exposure rates [in milli-Roentgen/hour, mR/hr] from injected patients at 1 meter distance were measured at 10 minutes, 1 hour and at time of releasing patients in both groups. Total 369 patients were included and 104 [28%] patients had stress-only and 265 [72%] had stress-resting studies. Mean administered [99m]Tc-MIBI dose in Stress-only and Stress-rest groups was 8 +/- 1 mCi and 24 +/- 03 mCi respectively [p<0.05]. Exposure rates[in mR/hr] within 10 min, 1 hour and at release time in Stress-only and stress-rest groups were 0.394, 0.294, 0.194and 1.540, 1.431, 1.207 respectively [p<0.05]. Mean stay of patients in laboratory was 90 +/- 39 minute in Stress-only and 156 +/- 53 minute in Stress-Rest group [p <0.0001]. There was a significantly widening gap between exposure rates from patients with Stress-only and stress-rest protocols as 26:74%, 21:79% and 16:84% at 10 min, 1 hour and at time of release respectively. We conclude that adopting a Stress-only MPI protocol in low risk patients ensures significantly lower radiation doses to patients and technologists. A worldwide paradigm shift in nuclear cardiology practice would safe mankind from unjustified radiation exposure
ABSTRACT
Molybdenum-99 breakthrough is a rare but potential cause of enormous and unjustified radiation exposure to patients and technologist in nuclear medicine. Recommended limit of [99] Mo in an eluate is 0.15 uCi of [99] Mo / mCi of [99m]Tc. The purpose of this clinical audit was to measure the Mo-99 concentration in eluate of PAKGEN [[99] Mo-[99m]Tc generator] before administering to patients as a part of Good Medical Practice [GMP]. This clinical audit was conducted at The Aga Khan University Hospital, Karachi from January to May 2012 and during this period we evaluated 44 [99] Mo-[99m] Tc generators [PAKGEN]. In 369 elutions during this audit period, we did not find any evidence of [99] Mo breakthrough. This clinical audit proves that PAKGEN generators supplied by IPD, PINSTECH, Islamabad had good performance and proved generally to be a reliable source of [99m] Tc-pertechnetate. The application was safe and fulfilled the requirements for good medical practice
ABSTRACT
Paraganglioma are tumors originating from paraganglial system and may be associated with parasympathetic [head, neck and anterior mediastinum tumors] or sympathetic [adrenal or extraadrenal or posterior mediastinal tumor] system. Majority of sympathetic paraganglioma and minority of parasympathetic tumor are functional and [131I or [132]I labeled MIBG [Meta Iodio Benzyl Guanidine] is a well established tool with good sensitivity and exceedingly high specificity. We are presenting a case report of a large extradrenal paraganglioma with extensive bony metastases and raised serum Chromogranin-A level. In this case [131]-MIBG was not only helpful in revealing the true burden of functional disease but also showed an overwhelming therapeutic response proven on post-therapy MIBG scan and normalization of serum Chromogranin-A level. This case report is followed by a mini-review about pathology, genetic mutation, diagnosis and treatment of focused on extraadrenal paragangliomas
ABSTRACT
Obesity is generally considered as a risk factor for coronary artery disease [CAD] and cardiac deaths but some reports suggest better survival in obese with CAD. The objective of this study was to find out predictive value of body mass index [BMI] and waist circumference [WC] for CAD and its outcome using gated myocardial perfusion imaging [GMPI]. This was a prospective study conducted at Nuclear Cardiology Department of Karachi Institute of Heart Diseases [KIHD], Karachi, Pakistan from August 2011 till May 2013. 400 patients who qualified study criteria were included and were divided in [a] to Obese [BMI30 Kg/m[2]] and Non-obese [BMI<30 Kg/ m[2]] and [b] Low-WC group [male<90 cm and female < 80 cm] and High-WC group [male 90 cm and female 80 cm]. Rest and stress GMPI using Tc-99m MIBI was performed in all patients and abnormal GMPI was followed by coronary angiogram. These patients were followed for 12-18 months regarding fatal and non-fatal events. Non-Obese group included 281 patients [Male: Female = 131:150] with a mean age of 58 +/- 12 years and mean WC 100 +/- 15 cm. Obese group included 119 patients [Male: Female = 36:83] with a mean age of 55 +/- 11 years and mean WC 101 +/- 13 cm. Normal GMPI was found in 172 non-obese and 85 obese patients [p<0.05]. GMPI was abnormal in 109 non-obese and 34 obese patients [p<0.05]. WC was not found independent predictor of abnormal GMPI but high WC was found to a significant predictor of CAD in non-obese females [Odd ratio 8.04; 1.041 - 62.127]. At 18 months event-free survival in normal GMPI group for non- fatal MI was 99.4% in non-obese group and 94.1% for obese [significant P value]. For fatal MI, event-free survival was 99.4% in non-obese and 100% for obese [non-significant P value]. In patients with abnormal GMPI event-free survival for non-fatal events was 95.4% in non-obese group and 82.3% in obese group [significant P value]. While event-free survival for fatal MI was 96.3% in non-obese group and 98.1% for obese [significant P value]. We conclude that CAD was found less prevalent in obese group and High-WC predicted CAD in non-obese females only and was not found an independent predictor. A normal GMPI predicted very high event free survival for fatal events in obese and non-obese but significantly lower for non-fatal events in obese group. Obese group with abnormal GMPI had lower risk for cardiac deaths but higher risk for non-fatal events than non-obese patients with abnormal scans
ABSTRACT
Solitary metastasis involving sternum in breast cancer is very uncommon and less is known about the possible mechanism. Similarly, clinical significance of this uncommon presentation is elusive. We are presenting a case of breast cancer with isolated sternal metastasis on radionuclide bone scan which was also documented on chest CT study. In this mini-review we will be discussing the possible mechanisms for isolated sternal metastasis in breast cancer, its clinical significance and therapeutic approaches used
ABSTRACT
To assess early nephrotoxicity of CDDP [Cis-diamminedichloroplatinum] manifested by a decline in the glomerular filtration rate [GFR] estimated by plasma two sample clearance method [PSC 2] after 99mTc.DTPA injection. Descriptive study. Department of Nuclear Medicine, Karachi Institute of Radiotherapy and Nuclear Medicine, Karachi, from September 2004 to January 2005. The renal function was assessed on 36 patients suffering from different types of cancer and receiving CDDP in doses of >/= 50 mg/m[2] before and after in each of six CDDP cycles. The GFR was determined by PSC 2 method after 99mTc-DTPA injection]. A paired sample t-test was used for comparison of the mean value with significance at p < 0.01. There were [28 males and 8 females; age range being 16-68 years]. The average decline in GFR baseline to the end of sixth cycles was 43.86 ml/min/1.73m[2] [p=0.000] as estimated by PSC 2 method. There was a significant fall of average 9.36 ml/min/1.73m[2] [p <0.01] in GFR as observed in each cycle of CDDP estimated by the PSC 2 method. In the initial four cycles, CDDP produced a major nephrotoxic effect of average 10.27 ml/min/1.73m[2] [p <0.01] fall in GFR. This then gradually declined to a plateau of an average decline in GFR of 7.76 and 7.31 ml/min/1.73m[2] [p=0.000] after the 5[th] and 6[th] cycle respectively. CDDP produced an early nephrotoxicity which was manifested by a significant decline in GFR in each cycle. Tc-99m PSC 2 method for GFR estimation should be used periodically for the early detection of nephrotoxicity induced by CDDP
Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Aged , Kidney/drug effects , Glomerular Filtration Rate/drug effects , Kidney Function Tests , Radioisotope Renography , Early DiagnosisABSTRACT
To determine the role of dual phase 99mTc-MIBI scintimammography in predicting chemotherapeutic response in breast cancer. Cross-sectional study. Karachi Institute of Radiology and Nuclear Medicine [KIRAN], from September 2004 to March 2005. Female patients with locally advanced breast cancer being planned for the anthracycline-based neoadjuvant chemotherapy were included in this study. All subjects received a 740 MBq bolus intravenous injection of 99mTc-MIBI. Ten minutes and 3 hours post-injection planar images were obtained in prone, lateral and supine positions using double head gamma camera. MIBI washout was scored as follows: > 30% as a positive prognostic test [predicting a poor response to chemotherapy] and < 30% as negative prognostic test [predicting a good response to chemotherapy]. Qualitative analysis of MIBI scans was also performed and categorized as visual wash-out or no visual washout as apparent on the early and delayed images. The criterion for the good and bad response was the reduction of > 50% and < 50% in the tumour burden respectively. Accuracy analysis, Chi-square test and Wilcoxan sign rank test were applied. There were 32 females [mean age: 46.3 years; median age 46 years; age range 33-65 years]. Quantitative dual phase 99mTc-MIBI scintimammography was found to be a good predictor of chemotherapeutic response in breast cancer. These were true positive in 8 patients and true negative in 19 patients with sensitivity [Sens.] 72%, specificity [Spec.] 90%, Positive Predictive Value [PPV] 80%, Negative Predictive Value [NPV] 86.5%, p < 0.03. Receiver Operating Characteristics [ROC] curve analysis demonstrates 30% as a cut-off value for the wash-out in quantitative dual phase MIBI for the prediction of the chemotherapeutic response. In comparison, qualitative scintimammography had Sens. 82%, Spec. 53%, PPV 29%, NPV 93% and p < 0.38. Statistical difference was found between early and delayed uptake ratios in the responders and non-responders. Quantitative dual phase 99mTc-MIBI scintimammography is a simple, reliable, non-invasive and effective tool for predicting the response to neoadjuvant chemotherapy. Furthermore, quantitative assessment is more precise than qualitative [visual wash-out] approach
Subject(s)
Humans , Female , Neoadjuvant Therapy/methods , Technetium Tc 99m Sestamibi , Radionuclide Imaging , Chemotherapy, Adjuvant , Cross-Sectional StudiesABSTRACT
To compare diagnostic accuracy of predicted clearance method, Gates method. Cockcroft-Gault method and plasma 1-sample clearance method with plasma 2-samples clearance method with Tc-99m DTPA for the estimation of glomerular filtration rate[GFR]. This study included 91 consecutive patients who were referred for evaluation of renal function to the Nuclear Medicine section of Karachi Institute of Radiotherapy and Nuclear Medicine [KIRAN] from September 2004 to September 2005. The GFR was determined simultaneously by 5 methods including Plasma two-Sample Clearance method after Tc-99m DTPA injection [PSC 2]; Plasma one-Sample Clearance method after Tc-99 m DTPA injection [PSC I]; Gamma camera uptake method after Tc-99m DTPA injection [Gates method]; Predicted Creatinine Clearance by Modification of Diet and Renal Diseases [MDRD]: and Cockeroft-Gault's equation for GFR estimation [CG]. PSC 2 was chosen as a reference, Out of the 91 patients, 71 were males and 20 females with age ranging from 16-68 years. The regression equation of the PSC 1, Gates, MDRD and CC method against the NC 2 was Y = 1.884+0.970X [r=0.90, p<0.001, SEE value-10, 23 ml/min/1.73m2]. Y = - 9.944 + l.083X [r=0.82, p<0.001, SEE valuel=11.02 mI/min/1.73m2], Y=25.606+0.640X [r=0.71, <0.002, SEEvaIuc=15.56 ml/min/1.73m2], and Y=14.9811-0.714X [r=0.77, p=0.002, SEE value=14.44 mI/min/1.73m2] respectively. In comparison with the GFR by PSC 2, the PSC I and Gates tended to overestimate by 1% [p=0.359] and 2% [p=0.265] respectively, MDRD and CC tended to underestimate GER by 11% and 14% respectively [p<0.001] PSC I correlate well with PSC 2 and either can be substituted for the other as ideal GFR markers. The Gates method shows good correlation with PSC 2 however it is less precise than PSC I. MDRD and CG methods due to significant underestimation are not considered as ideal GFR marker