The role of F-18 FDG PET/CT in differentiating benign from malignant pulmonary masses and accompanying lymph nodes.

INTRODUCTION: The aim of this study was to evaluate the usefulness of SUVmax and lesion size to differentiate benign and malignant lesions of the lung and accompanying mediastinal lymph node on F-18 FDG PET/CT imaging. MATERIALS AND METHODS: A retrospective analysis was carried out on 100 patients with suspected lung cancer who were recommended for PET/CT scans for diagnosis and staging. The results of the SUVmax, lesion size and patient's age were compared with histopathology which was considered to be the 'gold standard' and sensitivity and specificity were calculated respectively. Lymph nodes greater than 1 cm in patients with benign pathology were evaluated and the SUVmax values were recorded. RESULT: Of the 100 patients, 38 were found to have benign, whereas 62 had malignant on histopathology. The SUVmax was significantly more elevated in malign masses (13.1 ± 6.4) than in benign masses (8 ± 5.7) (p< 0.05). The dimensions of malignant masses (4.5 ± 2.5 cm) were larger than benign ones (3 ± 1.6 cm) (p< 0.05). SUVmax of 7.6 was determined as the cut-off value, while the sensitivity and specificity were 82% and 55% respectively. The sensitivity was 87% and specificity was 45% for the lesion sizes in differentiation of the malignant and benign lesions. CONCLUSIONS: There are significant overlaps between benign and malignant lesions and specialists must be aware of the various pathological conditions that can give false positives and negatives.

Parathyroidectomy in asymptomatic primary hyperparathyroidism reduces carotid intima-media thickness and arterial stiffness.

OBJECTIVE: Although an International Workshop has suggested that cardiovascular assessment in asymptomatic primary hyperparathyroidism (PHPT) patients is not necessary, improvements in risk factors of subclinical atherosclerosis have been shown following parathyroidectomy. The objectives of this study were to determine whether parathyroidectomy in asymptomatic PHPT patients causes any change in carotid intima-media thickness (CIMT), arterial stiffness [pulse wave velocity (PWV)] and soluble CD40 ligand (sCD40L) levels. DESIGN: Prospective study evaluating female patients diagnosed with asymptomatic PHPT in a single centre over a 6-month period. PATIENTS: A total of 48 subjects were included: 17 hypercalcaemic (HC, mean age: 51 ± 8 years, Ca: 2·73 ± 0·17 mmol/l) and 16 normocalcaemic (NC, mean age: 58 ± 7 years, Ca: 2·30 ± 0·10 mmol/l) PHPT patients, and 15 healthy controls (mean age: 52 ± 4 years, Ca: 2·27 ± 0·07 mmol/l). MEASUREMENTS: Biochemical tests, CIMT, PWV and sCD40L levels were compared at baseline and 6 months after parathyroidectomy (PTx). RESULTS: At baseline, CIMT and PWV values in the HC and NC patients were higher than in the control group. While there was a significant reduction in CIMT (601 ± 91 µm vs 541 ± 65 µm, P = 0·006) and PWV (9·6 ± 1·8 vs 8·4 ± 1·5 m/s, P = 0·000) in the hypercalcaemic group at the end of the 6th month after PTx, no change was observed in normocalcaemic group (P = 0·686 and P = 0·196 respectively). No differences were observed in sCD40L levels between patient and control groups or between baseline and 6 months in patients undergoing parathyroidectomy. CONCLUSION: Parathyroidectomy leads to an improvement in the structural and functional impairment associated with atherosclerosis in the vascular wall in asymptomatic hypercalcaemic PHPT patients.

Is there any relation between PET-CT SUVmax value and prognostic factors in locally advanced breast cancer?

PURPOSE: To investigate the relation between PET-CT SUVmax value and prognostic factors in locally advanced breast cancer. METHODS: Data of 73 patients were retrospectively analyzed. Relations between SUVmax value, clinical stage, tumor grade and breast cancer molecular subtypes were analyzed by using one-way ANOVA and x(2) tests. Correlations between age, ki-67 scores and SUVmax were evaluated by using Pearson's correlation test. A p value <0.05 was considered statistically significant. RESULTS: Median SUVmax values for clinical stages 1, 2 and 3 were 5 (range 2.1-4.1), 10.6 (range 2.9-19.6), and 12.2 (range 3.2-23.3), respectively. Statistically significant difference was noticed between stage 1 and 2 (p=0.014) and stage 1 and 3 (p=0.001). Median SUVmax values of triple negative, luminal A, luminal B and non-luminal HER2 positive groups were 14.4 (range 6.6-23.3), 8.2 (range 2.1-18.2), 10.1 (range 3.5-19.6), and 14 (range 4.1-22.9), respectively. Statistically significant differences were noticed in SUVmax values between triple-negative and luminal A groups (p=0.005) and between non-luminal HER2 positive and luminal A groups (p=0.02). Median SUVmax values of grade 1, 2 and 3 were 5.7 (range 2.1-18.2), 9.5 (range 2.2-21.3), and 11.6 (range 3.5-23), respectively. Statistically significant difference was noticed only between SUVmax values of grade 1 and 3 (p=0.035). There was negative correlation between age and SUVmax value (r=-0.23, p=0.047) and positive correlation between ki-67 and SUVmax value (r=0.43, p=0.016). CONCLUSION: There were significant positive relations between PET-CT SUVmax value and clinical stage, tumor grade, and certain breast cancer molecular subtypes (triple-negative and non-luminal HER2 positive groups. Moreover, positive correlation was found between SUVmax value and ki-67 and negative correlation between SUVmax value and age.

Yttrium-90 radioembolization in patients with unresectable liver metastases: determining the factors that lead to treatment efficacy.

INTRODUCTION: Locoregional treatments, such as radioembolization, can be used to treat patients with unresectable liver metastases. We aimed to determine the progression-free survival and factors that predict survival of patients with liver metastases whose response to selective internal radiation therapy (SIRT) with Y-90 was assessed by positron emission tomography-computed tomography (PET-CT). PATIENTS: Our study included 78 liver cancer patients who were treated with Y-90 radioembolization. RESULTS: The post-treatment response rates were as follows: 7 patients (9%) had stable disease (SD), 26 patients (33.3%) had a partial response (PR), 4 patients (5.1%) had a complete response (CR). The median hepatic progression-free survival (HPFS) was 4.4 months while median overall survival was 10.1 months. Univariate analysis revealed that HPFS is significantly affected by international normalized ratio (INR) levels and age (Hazard Ratio(HR)=0.54 (95%CI:0.30-096), P=0.034, HR=1.03(95%CI:1.00-1.05), P=0.051). However, only INR levels retained significance with multivariate analysis (HR=0.53 (95%CI:0.30-0.93), P=0.028), while age had limited significance (HR =1.02 (95% CI:1.00-1.05), P=0.051). CONCLUSIONS: We determined that Y-90 radioembolization is effective as a salvage therapy in patients with predominant liver metastases. For the first time, we showed that age and INR values reflecting the functional hepatic reserve can be used as positive predictive factors for HPFS.

Intramuscular Granular Cell Tumor Detected on 68 Ga-PSMA PET/CT.

ABSTRACT: Finding of the prostate-specific membrane antigen (PSMA) is highly expressed in prostate cancer (PC) cells that have made it possible to evaluate the patients with PC with a single imaging method. 68 Ga-PSMA PET/CT is now part of the routine in patients with PC. After several years of clinical experience with PSMA tracers, the specificity is satisfactory; however, concerns about the specificity are raising day by day due to the newly laid out nonprostatic malignant and benign lesions with high PSMA expression. Herein, we present an incidental 68 Ga-PSMA uptake in an intramuscular granular cell tumor.

A Rare Case and Atypical Metastatic Regions, Pulmonary Giant Cell Carcinoma.

Sixty two years old man referred to our clinic due to suspicion of thymic mass. The hypermetabolic nodular lesion in the right lung upper lobe was seen in 18F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography (PET/CT) in addition to the mass in the anterior mediastinum which was found to without malignancy. The patient underwent wedge resection and final diagnosis was pulmonary giant cell carcinoma. In follow-up 18F-FDG PET/CT multiple lesions with pathological activity were observed in the cerebrum, right postauricular region, bilateral adrenal, stomach, pancreas, pelvic soft tissue, mesenteric, left femur and bilateral lung parenchyma 6 months after. The pathology results of the right frontal, pelvic mass and the postauricular region were metastasis.

Intraoperative Parathyroid Hormone Monitoring-Guided Subtotal Parathyroidectomy is an Effective and Valid Surgical Procedure for Secondary Hyperparathyroidism.

Objectives: Secondary hyperparathyroidism (sHPT) is a prevalent complication of end stage renal disease in which serious morbid conditions and mortality can be encountered. Although the best solution of this severe problem is renal transplantation, because of the huge demand and limited resources, this cannot be possible most of the time. Initial treatment alternative is medical treatment in patients with sHPT and parathyroidectomy (PTX) should be applied if does not help. Subtotal PTX, total PTX and total PTX together with autotransplantation are the current surgical options preferred for sHPT. Intraoperative parathyroid hormone (IO PTH) monitoring can increase surgical success in sHPT. We aimed to determine the ideal surgical technique and relation of IO PTH monitoring with surgical success in patients with sHPT through our study. Methods: We analyzed all the data of the 35 patients who had PTX and follow up between January 2001 and December 2021 because of sHPT at General Surgery Department of Akdeniz University Medical Faculty Hospital in retrospective manner. Results: Twenty-seven of the patients had been applied subtotal PTX while six of the cases had experienced limited surgery and two of them had undergone total PTX. Persistance happened to be present in the follow-up of nine patients and recurrence in one of them. Four persistant and one recurrent cases were present in 23 patients with IO PTH monitoring (78.3% surgical success), while there were persistences in each of the three patients with no IO PTH monitoring (0% success of surgery) (p=0.022). IO PTH monitoring data of nine patients could not be reached. In this study, 20 patients had IO PTH decline of 80% or more (90% surgical success) and three patients had IO PTH decline below 80% (0% surgical success) (p=0.006). Subtotal PTX was applied to 17 (94.1% surgical success) of these 20 patients. Conclusion: In surgical treatment of patients with sHPT, IO PTH monitoring should be maintained and operation should not be finished until 80% or more decline in IO PTH level had been detected. Among the surgical alternatives for sHPT, subtotal PTX appears as an effective and valid method when performed together with IO PTH monitoring, provided that there is a decline in PTH level of 80% or more.

Spontaneous periodic hypothermia and hyperhidrosis.

We present a patient diagnosed with Shapiro syndrome without corpus callosum agenesis. A 4-year-old-girl was admitted to the hospital with complaints of sweating, cooling, and drowsiness that continued during the last week of her admission. Attacks occurred almost daily, and lasted for about 1 hour. All laboratory findings, as well as Holter and echocardiography results, were normal. Cranial magnetic resonance imaging demonstrated an intact corpus callosum, and electroencephalography obtained during an attack revealed normal findings. However, technetium 99m-labeled hexamethylpropylene amine oxime brain single-photon emission computed tomography indicated increased perfusion in the right thalamus, basal ganglia, and inferior frontal areas during a hypothermic period. Although oxcarbazepine reduced the frequency of attacks, they were not halted completely. The patient responded better to carbamazepine.

Technetium-99m hexamethyl propylene amine oxime-labeled leukocyte scintigraphy at three different times in active ulcerative colitis: comparison with colonoscopy and clinico-biochemical parameters in the assessment of disease extension and severity.

OBJECTIVE: In this study, our objective was to define the usefulness of technetium-99m hexamethyl propylene amine oxime (Tc-99m HMPAO)-labeled leukocyte scintigraphy at three different time points in the assessment of disease extension and severity in patients with active ulcerative colitis (UC). METHODS: Twenty-one consecutive patients (10 women, 11 men; mean age 42.4 +/- 12 years) with active UC were prospectively studied. All patients were diagnosed by colonoscopy and histopathology prior to inclusion. Scintigraphy was performed at 1 h, 2 h, and 4 h after Tc-99m HMPAO-labeled leukocyte injection. Clinic-biochemical activity score, total colonoscopic activity score, and total scintigraphic activity score at 1 h, 2 h, and 4 h were calculated for each patient. RESULTS: Sensitivity, specificity, and accuracy values of Tc-99m HMPAO-labeled leukocyte scintigraphy were calculated as follows, respectively: 1 h imaging 86%, 73%, and 83%; 2 h imaging 89%, 74%, and 86%; 4 h imaging 90%, 58%, and 83% in the detection of active inflammatory segments. Even though no statistically significant difference was found between 1 h, 2 h, and 4 h imaging with respect to the sensitivity, specificity of labeled leukocyte scintigraphy, the largest area under the curve value was found for 2 h imaging. CONCLUSIONS: Tc-99m HMPAO-labeled leukocyte scintigraphy has been found to be correlated well with colonoscopy in the assessment of both the extension and severity of UC. We recommend 2 h scintigraphic imaging because it provides the largest area under the curve value and decreases the number of false-positive results.

Bone metastases without primary tumor: A well-differentiated follicular thyroid carcinoma case.

Metastases to the bone are the most common malignant bone tumors. Prostate, breast, and lung carcinomas are the most common primaries of bone metastases. Bone metastases show poor prognosis in means of median survival; however, some patients with highly curable tumors such as thyroid carcinoma may benefit from treatment. We report and discuss a unique case of a 70-year-old female patient presenting with arm pain, diagnosed with metastatic well-differentiated follicular carcinoma without a primary tumor in the thyroid.

Efficacy of 18F-2-fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computerized Tomography for Bone Marrow Infiltration Assessment in the Initial Staging of Lymphoma.

OBJECTIVE: Currently 18F-2-fluoro-2-deoxy-D-glucose (18F-FDG) positron emission tomography/computerized tomography (PET/CT) is being successfully used for staging and follow-up of Hodgkin's lymphoma (HL) and non-Hodgkin's lymphoma (NHL). Various studies have demonstrated that PET/CT effectively detects bone marrow involvement (BMI) and is concordant with bone marrow biopsy (BMB) findings, thus it is deemed as a complementary method. This study was aimed to evaluate18F-FDG-PET/CT efficiency for detection of BMI in HL and NHL. METHODS: The study included 172 lymphoma cases who were admitted to Akdeniz University Medical School Department of Nuclear Medicine for initial staging with PET/CT. Visual and semiquantitative assessments were performed for PET/CT scan findings of the cases. The maximum standard uptake (SUVmax) value was the quantitative parameter used for 18F-FDG-PET scan. In visual assessment, bone marrow metabolic activity that is greater than the liver was considered as pathologic. For semiquantitative assessment, regions of interest were drawn for SUVmax estimation, which included iliac crest in cases with diffusely increased metabolic activity and the highest activity area in cases with focal involvement. BMB was considered as the reference test. RESULTS: On visual assessment of all the cases, PET/CT was found to yield 31% sensitivity and 85% specificity rate for detection of BMI. On visual assessment of HL cases, sensitivity rate was determined as 80%, and specificity as 78%, while in NHL cases the corresponding values were 24% and 90%, respectively. On semiquantitative assessment of HL cases, considering SUVmax≥4, sensitivity was found as 80% and specificity as 68%. In NHL patients, considering SUVmax≥3.2, sensitivity rate was detected as 65% and specificity as 58%. CONCLUSION: In this study, a moderately high concordance was observed between PET/CT and BMB findings. PET/CT appears to be a significant method for detecting BMI. Although PET/CT is not a substitute for BMB, we suggest it can be used as a guide to biopsy site and a complementary imaging technique for BMB.

Leptin levels and body composition in children and adolescents with type 1 diabetes.

The purpose of this study was to determine the relationship between serum leptin levels and body composition and to evaluate the variables related to disease in children and adolescents with type 1 diabetes. We studied 49 diabetic patients aged 6-16 years (age: 11.2+/-2.9 years, M/F: 26/23), and 37 healthy controls. Body composition was determined by dual-energy X-ray absorptiometry. Serum leptin, glycated hemoglobin (HbA1c), free thyroxin, thyrotropin, testosterone and estradiol levels were measured in patients and controls. We did not observe significant difference in serum leptin levels between patients and controls. Girls had significantly higher serum leptin levels than boys in both patient and control groups. Serum leptin levels did not correlate significantly with HbA1c, disease duration or daily insulin dose but, correlated positively with body mass index (BMI) and fat mass (FM) in patients as in controls. Body composition in diabetic girls and boys was similar with respective controls. When analyzed by pubertal stage, BMI, lean body mass (LBM), FM, and total bone mineral density (BMD) were significantly higher in pubertal girls with type 1 diabetes compared to prepubertal ones. In pubertal boys with type 1 diabetes, LBM and FM were significantly higher than prepubertal ones. The results of the present study showed that neither serum leptin levels nor body composition was significantly altered in children and adolescents with type 1 diabetes managed with intensive insulin therapy.

Bone mineral density and alterations of bone metabolism in children and adolescents with type 1 diabetes mellitus.

OBJECTIVES: To analysis bone mineral density (BMD) and bone turnover markers in children and adolescents with type 1 diabetes mellitus (DM1) and to establish possible correlations with duration of the disease and degree of metabolic control. PATIENTS AND METHODS: Fifty-eight (26 prepubertal, 32 pubertal) children (29 boys) with DM1 (age: 11.7 +/- 3.1 years) and 44 (20 prepubertal, 24 pubertal) healthy children (21 boys) as controls (age: 10.8 +/- 3.2 years) were included in the study. BMD was measured by dual energy X-ray absorptiometry (DEXA). Scans of the lumbar spine (LS2-4) and femoral neck (FN) were carried out. Serum levels of osteocalcin, amino-terminal propeptide of type I procollagen (PINP), and alkaline phosphatase, as markers of bone formation, and urinary calcium/creatinine (Ca/Cr) ratio and levels of N-telopeptide (Ntx), as markers of bone resorption, were assessed. Anthropometrics, duration of DM1, presence of complications, insulin dose, and degree of metabolic control were obtained from the patients' records. RESULTS: In children with DM1 and controls, the mean measurements of LS2-4 BMD were 0.698 +/- 0.178 g/cm2 and 0.669 +/- 0.192 g/cm2, respectively (p >0.05), and FN-BMD measurements were 0.743 +/- 0.147 g/cm2 and 0.744 +/- 0.170 g/cm2, respectively (p >0.05). Children with DM1 had lower serum levels of calcium, intact parathyroid hormone, osteocalcin and PINP, and higher serum levels of 25-hydroxyvitamin D and urinary Ca/Cr (p <0.05). BMD was not related to any of the markers of bone resorption or formation, duration of the disease, or degree of metabolic control. CONCLUSIONS: Although we did not establish decreased LS2-4 and FN-BMD measurements in patients with DM1, we found reduced bone formation and increased bone resorption markers in children with DM1. Measurements of serum osteocalcin, PINP, urinary Ntx and Ca/Cr might be useful for long-term follow-up in children and adolescents with DM1.

Tc-99m HMPAO brain SPECT findings in mild and moderate Alzheimer's disease: correlation with event related potentials.

We investigated whether brain SPECT findings show any differences between patients with mild and moderate Alzheimer's disease (AD) and to compare results with event related potentials (ERPs). Twenty-two patients with mild to moderate AD diagnosed according to NINCDS-ADRDA criteria and 10 age-matched control subjects were included in this prospective study. All subjects underwent ERP recordings and Tc-99m HMPAO brain SPECT study. Cortical perfusion index (CPI) was calculated as the ratio of cortical activity to the cerebellum activity. CPI was found to be statistically lower in bilaterally posterolateral temporal cortex and precuneus in the moderate AD compared to the control group. There was no statistically significant difference between the mild AD and control groups for CPI in any cortical areas. The mean P300 latency was statistically prolonged in the mild and moderate AD compared to the control group. In addition, in moderate AD P300 latency was longer than in mild AD. While the mean P300 amplitude was statistically reduced in moderate AD compared to the control and mild AD, there was no statistically significant difference between the mild AD and control groups. There was a strong negative correlation between P300 latency and CPI in the right and left precuneus in the moderate AD group. The present study suggested that Tc-99m HMPAO SPECT study is the more appropriate technique for patients with moderate AD rather than mild AD. Our results indicated that alterations in ERPs, especially prolongation of P300 latency could be a finding that occurred earlier than the deterioration in cerebral blood flow. We thought that precuneus is closely related to cognitive function and may have an important role in the pathophysiology of AD.

Assessment of percutaneous coronary intervention on regional and global left ventricular function in patients with chronic total occlusions.

BACKGROUND: The improvement of regional and global ventricular function following percutaneous coronary intervention (PCI) with reperfusion of the artery supplying the infarct area in acute myocardial infarction is well-described. However, little is known of the potential effects of late recanalization of chronic coronary artery occlusion on left ventricular function. OBJECTIVE: To determine whether PCI improves regional and global left ventricular function in patients with chronic coronary artery occlusions. PATIENTS AND METHODS: Thirty-five patients having at least one coronary artery occluded for six weeks or longer were included in the present prospective study. Exercise thallium-201 myocardial perfusion scintigraphy, multiple-gated acquisition ventriculography and two-dimensional echocardiography were performed in 19 patients (16 men; mean age of 58+/-5 years) who underwent a successful PCI to assess both regional and global left ventricular function before and six weeks following the procedure. RESULTS: The mean ejection fractions before and after reperfusion were 51+/-7% and 58+/-6% using Simpson's method (P<0.001) by echocardiography, and 45+/-1% and 53+/-1% (P=0.01) by multiple-gated acquisition ventriculography, respectively. The echocardiographic wall motion score was 24+/-9 before and 15+/-6 after PCI (P<0.001). The exercise perfusion score (21+/-1 and 14+/-1 [P=0.01]), rest perfusion score (15+/-1 and 12+/-1 [P=0.02]) and reinjection perfusion score (14+/-1 and 11.1+/-1 [P=0.07]) also improved after PCI. The presence of angina was strongly associated with an improvement in left ventricular function and wall motion score (P<0.01). CONCLUSIONS: PCI significantly improved the regional and global left ventricular function in patients with chronic total coronary occlusion. This procedure may provide symptom benefits in selected patients.

A case of plastron appendicitis mimicking malignant cecal tumor in flourodeoxyglucose-positron emission tomography/computed tomography study.

In recent years, flourodeoxyglucose-positron emission tomography/computed tomography (FDG PET/CT) has been used intensively in the field of oncology. However, an increase in FDG uptake has been observed both in malignant tissues, and inflammatory processes. Therefore false-positive results have appeared. We present a 70-year-old male patient who presented to the hospital with right lower quadrant pain. A right lower quadrant mass was observed with conventional methods, and PET/CT was performed which revealed a hypermetabolic mass in the right lower quadrant. The patient was referred to the surgery with a suspect malignant mass whose histopathological report indicated plastron appendicitis. Although FDG PET/CT is a reliable method in the evaluation of oncological cases, false-positivities should be taken into consideration in inflammatory processes.

Left Vocal Cord Paralysis Detected by PET/CT in a Case of Lung Cancer.

We report a patient with lung cancer. The first PET/CT imaging revealed hypermetabolic mass in the left aortopulmonary region and hypermetabolic nodule in the anterior segment of the upper lobe of the left lung. After completing chemotherapy and radiotherapy against the primary mass in the left lung, the patient underwent a second PET/CT examination for evaluation of treatment response. This test demonstrated, compared with the first PET/CT, an increase in the size and metabolic activity of the primary mass in the left lung in addition to multiple, pathologic-sized, hypermetabolic metastatic lymph nodes as well as multiple metastatic sclerotic areas in bones. These findings were interpreted as progressive disease. In addition, an asymmetrical FDG uptake was noticed at the level of right vocal cord. During follow-up, a laryngoscopy was performed, which demonstrated left vocal cord paralysis with no apparent mass. Thus, we attributed the paralytic appearance of the left vocal cord to infiltration of the left recurrent laryngeal nerve by the primary mass located in the apical region of the left lung. In conclusion, the knowledge of this pitfall is important to avoid false-positive PET results.

Evaluation of factors affecting tumor response and survival in patients with primary and metastatic liver cancer treated with microspheres.

OBJECTIVE: Radioembolization with the yttrium-90 (Y-90) microspheres is being used increasingly more often in the treatment of patients with primary or metastatic liver cancer. Although technetium-99m macroaggregated albumin (Tc-99m MAA) scintigraphy performed following diagnostic angiography has an important role in predicting the effectiveness of treatment and in dose estimation, the number of studies using quantitative assessment of Tc-99m MAA scintigraphy is limited in this field. In the present study, the aim was to assess whether a tumor dose is required to obtain objective tumor response and to check whether this threshold value is predictive in terms of tumor response, survival, and liver toxicity by using Tc-99m MAA single-photon emission computed tomography (SPECT) images. MATERIALS AND METHODS: Overall, 54 patients (20 women and 34 men; median age: 60 years) who underwent Y-90 Resin (SIR-Spheres) and Glass (TheraSphere) microsphere treatment with a diagnosis of unresectable liver cancer between August 2010 and April 2013 were included in the study. The mean doses to normal liver and tumor were estimated for each patient using Tc-99m MAA SPECT images and the medical internal radiation dosimetry method. The responses were assessed according to Response Evaluation Criteria In Solid Tumors (RECIST) and European Organisation for Research and Treatment of Cancer (EORTC) criteria. Kaplan-Meier survival curves and univariate Cox regression analysis were used in survival analysis. The relationship between treatment response and other parameters included was assessed using logistic regression analysis. The variables with a P value less than 0.01 in univariate analysis were assessed with multivariate analysis. RESULTS: Fifty-four Y-90 microsphere treatments (eight by using a Y-90 glass microsphere and 46 by using a Y-90 resin microsphere) were performed. In the multivariate analysis, the only parameter related to response was tumor dose (P<0.01). With a tumor dose of 280 Gy or higher, objective tumor response was observed in 59 and 77% of the patients according to RECIST and EORTC criteria, respectively, and the tumor control rate was found to be 95% according to both criteria. In addition, it was found that only tumor dose was correlated with progression-free survival (PFS) (P<0.001) and overall survival (OS) (P=0.018). When the tumor dose was 280 Gy or higher, median PFS increased from 2 to 10.7 months (P<0.001), whereas median OS increased from 9 to 17.6 months (P=0.018). However, reversible ≥ G2 liver toxicity was observed in 3.7% (2/54) of the patients within 3 months after radioembolization with a median normal liver dose of 40 Gy (10-102 Gy). There was reversible ≥ G3 liver toxicity in 3.7% (2/54) of patients, but no G4 liver toxicity was observed. Clinical radiation hepatitis and treatment-induced liver failure were not observed in any of these patients. CONCLUSION: Tc-99m MAA SPECT has a predictive value in terms of response to radioembolization, PFS, and OS. Dosimetry based on Tc-99m MAA SPECT images can be used in the selection of patients and, in particular, to adaptation of treatment plan in selected patients.