Predictors of survival for breast cancer patients with a BRCA1 mutation.

PURPOSE: To evaluate in a contemporary cohort the impacts of chemotherapy and oophorectomy on survival for breast cancer patients with a BRCA1 mutation. EXPERIMENTAL DESIGN: We reviewed the pathology reports and medical records of 372 women with breast cancer and a BRCA1 mutation, diagnosed from 2005 to 2017, between the ages of 25 and 65 and followed them for death from all causes and death from breast cancer. Death was ascertained through the Poland vital statistics registry. We performed survival analysis to evaluate the impacts of chemotherapy (including neoadjuvant cisplatinum) and of oophorectomy on survival. RESULTS: After a mean follow-up of 5.6 years (median 5.2), 66 of the 372 women died; 56 of the deaths were from breast cancer and 6 were from ovarian cancer. 127 women received neoadjuvant cisplatinum and 245 women received other chemotherapies. Cisplatinum (versus all other therapies) was associated with a hazard ratio of 0.42 (95%CI 0.20-0.87) on breast cancer-specific survival. The 10-year actuarial all-cause survival for women who had both cisplatinum and an oophorectomy was 94.4%. The 10-year all-cause survival for women who had neither cisplatinum nor an oophorectomy was 65.4% (p < 0.01). CONCLUSIONS: Cisplatinum and oophorectomy are effective therapies for women with breast cancer and a BRCA1 mutation.

Nuclear medicine training and practice in Poland.

In Poland, nuclear medicine (NM) has been an independent specialty since 1988. At the end of 2013, the syllabus for postgraduate specialization in NM has been modified to be in close accordance with the syllabus approved by the European Union of Medical Specialists and is expected to be enforced before the end of 2014. The National Consultant in Nuclear Medicine is responsible for the specialization program in NM. The Medical Center of Postgraduate Training is the administrative body which accepts the specialization programs, supervises the training, organizes the examinations, and awards the specialist title. Specialization in NM for physicians lasts for five years. It consists of 36 months of training in a native nuclear medicine department, 12 months of internship in radiology, 3 months in cardiology, 3 months in endocrinology, 3 months in oncology, and 3 months in two other departments of NM. If a NM trainee is a specialist of a clinical discipline and/or is after a long residency in NM departments, the specialization in NM can be shortened to three years. During the training, there are obligatory courses to be attended which include the elements of anatomy imaging in USG, CT, and MR. Currently, there are about 170 active NM specialists working for 38.5 million inhabitants in Poland. For other professionals working in NM departments, it is possible to get the title of a medical physics specialist after completing 3.5 years of training (for those with a master's in physics, technical physics or biomedical engineering) or the title of a radiopharmacy specialist after completing 3 years of training (for those with a master's in chemistry or biology). At present, the specialization program in NM for nurses is being developed by the Medical Centre of Postgraduate Education. Continuing education and professional development are obligatory for all physicians and governed by the Polish Medical Chamber. The Polish Society of Nuclear Medicine (PTMN) organizes regular postgraduate training for physicians working in NM. Educational programs are comprehensive, covering both diagnostics and current forms of radioisotope therapy. They are aimed not only at physicians specialized/specializing in NM, but also at other medical professionals employed in radionuclide departments as well as physicians of other specialties.

Personalized image-based radiation dosimetry for routine clinical use in peptide receptor radionuclide therapy: pretherapy experience.

Patient-specific dose calculations are not routinely performed for targeted radionuclide therapy procedures, partly because they are time consuming and challenging to perform. However, it is becoming widely recognized that a personalized dosimetry approach can help plan treatment and improve understanding of the dose-response relationship. In this chapter, we review the procedures and essential elements of an accurate internal dose calculation and propose a simplified approach that is aimed to be practical for use in a busy nuclear medicine department.

Small cell carcinoma with neuroendocrine differentiation of subglottic larynx- a case report.

Small cell cancer (SCC) is a neuroendocrine neoplasm, which is most frequently found in the lungs. Extrapulmonary location of SCC is rare and may involve 2.5-5% of SCCs. We present a case of a 31-year-old male patient with an extremely uncommon subglottic SCC. The patient was qualified for a radical sequential chemoradiotherapy. After treatment, patient's condition suggested complete remission. Recurrence was detected one year later, and the disease rapidly progressed, despite a second line chemotherapy. The patient died 29 months after initial diagnosis. This case aims to raise awareness on the aggressive laryngeal SCC and its good response to first line chemotherapy composed of cisplatin and etoposide, followed by radiotherapy.

Individualization of Radionuclide Therapies: Challenges and Prospects.

The article presents the problems of clinical implementation of personalized radioisotope therapy. The use of radioactive drugs in the treatment of malignant and benign diseases is rapidly expanding. Currently, in the majority of nuclear medicine departments worldwide, patients receive standard activities of therapeutic radiopharmaceuticals. Intensively conducted clinical trials constantly provide more evidence of a close relationship between the dose of radiopharmaceutical absorbed in pathological tissues and the therapeutic effect of radioisotope therapy. Due to the lack of individual internal dosimetry (based on the quantitative analysis of a series of diagnostic images) before or during the treatment, only a small fraction of patients receives optimal radioactivity. The vast majority of patients receive too-low doses of ionizing radiation to the target tissues. This conservative approach provides "radiation safety" to healthy tissues, but also delivers lower radiopharmaceutical activity to the neoplastic tissue, resulting in a low level of response and a higher relapse rate. The article presents information on the currently used radionuclides in individual radioisotope therapies and on radionuclides newly introduced to the therapeutic market. It discusses the causes of difficulties with the implementation of individualized radioisotope therapies as well as possible changes in the current clinical situation.

Optimized method for normal range estimation of standardized uptake values (SUVmax, SUVmean) in liver SPECT/CT images with somatostatin analog [99mTc]-HYNIC-TOC (Tektrotyd).

BACKGROUND: 99mTc-hydrazinonicotinyl-Tyr3-octreotide ([99mTc]-HYNIC-TOC [Tektrotyd]) is a radiopharmaceutical used for the diagnosis of lesions with overexpression of somatostatin receptors. The purpose of this study was to optimize the method and estimate normal ranges for standardized uptake values of Tektrotyd in healthy livers. MATERIAL AND METHODS: An analysis of standardized uptake value (SUVs) normal ranges was performed for images acquired in a selected "healthy group" of 42 patients evaluated for neuroendocrin tumors. The "pathological group" comprised 20 patients with liver lesions detected by scintigraphic imaging. Normal ranges for radiopharmaceutical uptake values were estimated based on the quantitative analysis of images acquired with a GE Healthcare NM/CT 850 gamma camera. RESULTS: The method for healthy liver segmentation in single photon emission computed tomography/computed tomography (SPECT/CT) was optimized. The normal range of SUVs for the liver was: standardized uptake value body weight (SUVbw) max [5.2-14.0] g/mL and standardized uptake value lean body mass (SUVlbm) [3.5-9.5] g/mL. The relative standard error (relative SE) of activity concentration estimated in the phantom study for the largest hot spheres was: ϕ = 37 mm - 5.9%, ϕ = 28 mm - 7.1%, ϕ = 22 mm - 11.4%, and ϕ = 17 mm - 22%. CONCLUSIONS: Segmentation in the mid-coronal computed tomography (CT) image, at one-fourth of the height of the liver measured from the top, with a medium-sized volume of interest (VOI) outlined on a given transverse SPECT slice was regarded as the optimal method for estimating normal ranges for standardized uptake values. It is necessary to standardize quantification methods in the SPECT/CT studies. Our work is a step forward in obtaining standardization of SPECT/CT SUV calculation methods. Calculations for radiopharmaceutical uptake in tumors with volumes smaller than 5 mL are biased with a significant measurement error.

What validation tests can be done by the clinical medical physicist while waiting for the standardization of quantitative SPECT/CT imaging?

OBJECTIVE: The aim of the study was to assess the accuracy of quantitative SPECT/CT imaging in a clinical setting and to compare test results from two nuclear medicine departments. METHODS: Phantom studies were carried out with two gamma cameras manufactured by GE Healthcare: Discovery NM/CT 670 and NM/CT 850, used in two nuclear medicine departments. The data were collected using a cylindrical uniform phantom and a NEMA/IEC NU2 Body Phantom, filled with 99mTc-pertechnetate. RESULTS: The convergence of activity concentration recovery was validated for the two gamma cameras operating in two medical centers using the cylindrical uniform phantom. The comparison of results revealed a 5% difference in the background calibration factor Bg. cal; 6% difference in COV, and a 0.6% difference in total activity deviation ∆Atot. Recovery coefficients (RCmax) for activity concentration in spheres of the NEMA/IEC NU2 Body Phantom were measured for different image reconstruction techniques. RCmax was in the range of 0.2-0.4 for the smallest sphere (ϕ 10 mm), and 1.3-1.4 for the largest sphere (ϕ 37 mm). Conversion factors for SUVmax and SUVmean for the gamma camera systems used were 0.99 and 1.13, respectively. CONCLUSIONS: (1) Measurements taken in our study confirmed the clinical suitability of 5 parameters of image quality (Bg. cal-background calibration factor, ∆Atot-total activity deviation, COV-coefficient of variation used for image noise assessment, QH-hot contrast, AM-accuracy of measurements, or RC-recovery coefficient) for the validation of SPECT/CT system performance in terms of correct quantitative acquisitions of images. (2) This work shows that absolute SPECT/CT quantification is achievable in clinical nuclear medicine centers. Results variation of quantitative analyses between centers is mainly related to the use of different reconstruction methods. (3) It is necessary to standardize the technique of measuring the SUV conversion factor obtained with different SPECT/CT scanners.

Physical quantities useful for quality control of quantitative SPECT/CT imaging.

SPECT/CT imaging is transitioning from solely qualitative applications to quantitative analysis. Quantitative SPECT/CT systems require proper calibration, optimization and quality control. Various types of modern SPECT/CT scanners have different software for calibration and quality control (QC). There is still no standardization in this regard for quantitative SPECT/CT. This issue hinders the exchange of obtained results across centers and stunts the development of repeatable and reproducible measurements. The unification and standardization of calibration and quality control techniques for quantitative SPECT/CT systems is currently a pressing need for nuclear medicine departments. The present study presents three selected physical quantities characterizing the quality of quantitative SPECT/CT system and seven quantities, currently used in the literature, to assess the quality of quantitative SPECT/CT images. The measurement of these parameters requires the use of standard gamma camera software for QC, external programs for quantitative analysis of recorded data and clinical software. The authors hope this will help physicists who are willing to perform quantitative SPECT/CT in their departments.

Influence of high tissue-absorbed dose on anti-thyroid antibodies in radioiodine therapy of Graves' disease patients.

BACKGROUND: The results of radioactive iodine (RAI) treatment for Graves' disease (GD) are related to the choice of diagnostic and dosimetry protocols, the steroid protection used, and the subsequent 131I dose. The effect of a high tissue-absorbed dose on the level of anti-thyroid antibodies (ATA) has been rarely considered. OBJECTIVES: To estimate the effect of the first RAI therapy with a dose of 250 Gy on anti-thyreoperoxidase (anti-TPO) and anti-thyroid-stimulating hormone (TSH) receptor thyrotropin receptor antibody - TRAb levels in GD patients. MATERIAL AND METHODS: The analysis encompassed 46 consecutive patients with clinical presentation of GD. We examined the serum levels of TSH, free thyroxine (FT4), anti-TPO, TRAb, thyroid volume (ThV), 131I effective half-life (EHL), introduction of steroid protection, levothyroxine dose used in thyroid replacement therapy - TRT, and effectiveness of treatment. RESULTS: As a result of RAI treatment, hypothyroidism was found in 35 patients (76.1%), euthyroidism in 7 patients (15.2%) and hyperthyroidism in 4 patients (8.7%). After RAI, we observed ThV reduction and increased anti-TPO (p = 0.001 and p = 0.001, respectively). It was found that a shorter EHL correlated with a higher baseline TRAb concentration and lower final anti-TPO serum concentration (p = 0.03 and p = 0.01, respectively). Lower final TRAb was found in patients with steroid protection (p = 0.049). Intergroup comparison of patients without steroid protection showed significantly higher final anti-TPO concentation (p = 0.02). Intergroup comparison of patients with TRT revealed significantly higher final anti-TPO concentration (p = 0.04). CONCLUSIONS: The application of a high absorbed dose of 250 Gy in GD resulted in high efficacy of RAI therapy at 1-year follow-up. An increased ATA level and its relationships with EHL and ThV reduction were observed at 1-year follow-up. There is a possible relationship between steroid protection and anti-TPO concentration.

The Epidemiology and Clinical Presentations of Atopic Diseases in Selective IgA Deficiency.

Selective IgA deficiency (sIgAD) is the most common primary immunodeficiency disease (PID), with an estimated occurrence from about 1:3000 to even 1:150, depending on population. sIgAD is diagnosed in adults and children after the 4th year of age, with immunoglobulin A level below 0.07 g/L and normal levels of IgM and IgG. Usually, the disease remains undiagnosed throughout the patient's life, due to its frequent asymptomatic course. If symptomatic, sIgAD is connected to more frequent viral and bacterial infections of upper respiratory, urinary, and gastrointestinal tracts, as well as autoimmune and allergic diseases. Interestingly, it may also be associated with other PIDs, such as IgG subclasses deficiency or specific antibodies deficiency. Rarely sIgAD can evolve to common variable immunodeficiency disease (CVID). It should also be remembered that IgA deficiency may occur in the course of other conditions or result from their treatment. It is hypothesized that allergic diseases (e.g., eczema, rhinitis, asthma) are more common in patients diagnosed with this particular PID. Selective IgA deficiency, although usually mildly symptomatic, can be difficult for clinicians. The aim of the study is to summarize the connection between selective IgA deficiency and atopic diseases.

The occurrence of malignant thyroid lesions in patients after radioiodine treatment due to benign thyroid diseases.

INTRODUCTION: Radioiodine treatment (RT) of benign thyroid diseases is a well-known, safe, and effective treatment. In a group of patients after RT, who remained in long-term follow-up, sporadic cases of malignant thyroid lesions occurred. The aim of the study was to estimate how often it happened despite the exclusion of malignancy before RT. MATERIAL AND METHOD: A group of 4314 patients (7438 person-years) underwent RT and subsequently were followed-up for 1-8 years (mean 20.69 months). Apart from thyroid function estimation, if needed, fine needle aspiration biopsy (FNAB) of the thyroid or neck focal lesions was performed based on ultrasonographic or clinical examination. Patients with pathological FNAB were analyzed and histopathologically verified. RESULTS: In 12 out of 4314 cases (0.27%) suspicious FNAB results were found. Suspicious thyroid lesion results were found in 9 patients (8 F, 1 M), aged 46-73 (average 56 years) followed up for 3-57 months after RT: papillary cancer in two patients, Hürthle cell tumour in one patient, and suspicious cells in two patients (with benign lesions on postoperative histopathology). Two patients refused surgery (a suspicion of papillary cancer in one case and suspicious cells in FNAB in the second case). A follicular tumour in FNAB was suspected in two cases (no data about the first, and the second with lung cancer was not operable). In the remaining 3 cases FNAB revealed lymph node metastases due to other cancers. CONCLUSIONS: Malignant thyroid lesions in patients after RT due to benign thyroid diseases are seldom detected. However, periodical clinical and ultrasonographic evaluation is recommended.

The application of SPECT/CT scintigraphy with MIBI-Tc99(m) in the diagnosis of thyroid nodules - a preliminary report.

INTRODUCTION: Thyroid cancer diagnosis is based mainly on fine needle aspiration biopsy (FNAB) performed under ultrasonography guidance. Questions arise in cases of an inconclusive FNAB result - when there is no clear evidential data to support the existence of a malignant lesion or when there are any other reasons which make the decision process difficult, such as the patient's age or coexisting diseases. To clarify this issue the patient should be encouraged to undergo surgery treatment or to be followed up. Thyroid scintigraphy with an oncophilic tracer such as MIBI-Tc99(m) may be helpful. MATERIAL AND METHODS: The study comprised a group of 12 patients, aged 54-75 (av. 63.5) years, who, in 2009, underwent planar and SPECT/CT thyroid scintigraphy with MIBI-Tc99(m) using washout method. The tumour/background ratio in early and delayed images was calculated and the wash-out ratio was estimated. Patients with increased focal lesion uptake were operated on and the lesions were histopathologically verified. RESULTS: Abnormal scintigraphy results were obtained in 8 patients (10 lesions) and normal results in 4 patients (5 lesions). Out of 15 studies, in 13 cases the washout from the lesion was observed within 2 hours. It was noticed that the images obtained with SPECT/CT washout method were clearer and easier to read in comparison to planar studies. Three patients with an abnormal results underwent surgery and had benign histopathology results after the operation, in 3 patients the observation is being confirmed without any increase in malignancy suspicions, and 2 were lost for observation. CONCLUSIONS: Our preliminary results do support the use of MIBI-Tc99m in the evaluation of indeterminate thyroid nodules. To validate the hypothesis that MIBI-Tc99(m) may be used to exclude malignancy in lesions indeterminate by FNAB we propose to use SPECT-CT derived images and standardized evaluation criteria.

The diagnostic value of dual-phase SPECT/CT scintigraphy based on transport kinetics of 99mTc-sestamibi confirmed with histopathological findings in patients with secondary hyperparathyroidism - practical consideration.

BACKGROUND: Dual phase 99mTc-sestamibi SPECT/CT preoperative parathyroid scintigraphy (PPS) is seldom discussed in terms of the transport kinetics of the tracer. OBJECTIVES: To assess the relationship between the characteristic type of tracer transport in particular PPS and histopathological findings in patients with secondary hyperparathyroidism (sHPT). MATERIAL AND METHODS: The study comprised 27 patients (13 females and 14 males) with sHPT. Based on tracer accumulation in early phase (EP) and delayed phase (DP), the following types of accumulation for PPS(+) lesions were identified: EP(-)/ DP(+) (type I), EP(+)/DP(+) (type II), EP(+)/DP(-) (type III). EP(-)/DP(-) (type IV) lesions constituted PPS(-) group invisible in SPECT/CT. Overall, 69 lesions 59 PPS(+) and 10 PPS(-) were evaluated histopathologically. RESULTS: Among SPECT/CT PPS(+), types I, II and III occurred in 9 (15%), 49 (83%), and 1 (2%) lesions, respectively. The frequency of histopathological diagnosis of normal and abnormal (APG - adenoma or hyperplasia) parathyroid gland, as well as non-parathyroid (thyroid, lymph nodes, or fat) lesions differed significantly between type I, II, and III lesions (p = 0.036). APG histopathological diagnosis was significantly more frequent in lesions with type II uptake than in lesions with type I uptake (76% vs. 33%, p = 0.0197). Type II lesions had significantly higher odds for histopathological diagnosis of APG or NPG than type IV, PPS(-) lesions [odds ratio = 13.1 (95% CI: 2.75 to 63.27)]. CONCLUSIONS: For SHP patients evaluated with SPECT/CT PPS accumulation type I is a weak premise for surgeon to find parathyroid pathology. Only persistent 99mTc-sestamibi accumulation in both phases - equivocal with accumulation type II - effectively differentiates parathyroid and non-parathyroid lesions as well as indicates with high probability the presence of adenoma or hyperplasia. Type III consistent with washout pattern is rare in sHPT.

Newborn Screening for SCID and Other Severe Primary Immunodeficiency in the Polish-German Transborder Area: Experience From the First 14 Months of Collaboration.

In 2017, in the Polish-German transborder area of West Pomerania, Mecklenburg-Western Pomerania, and Brandenburg, in collaboration with two centers in Warsaw, a partnership in the field of newborn screening (NBS) for severe primary immunodeficiency diseases (PID), mainly severe combined immunodeficiency (SCID), was initiated. SCID, but also some other severe PID, is a group of disorders characterized by the absence of T and/or B and NK cells. Affected infants are susceptible to life-threatening infections, but early detection gives a chance for effective treatment. The prevalence of SCID in the Polish and German populations is unknown but can be comparable to other countries (1:50,000-100,000). SCID NBS tests are based on real-time polymerase chain reaction (qPCR) and the measurement of a number of T cell receptor excision circles (TREC), kappa-deleting recombination excision circles (KREC), and beta-actin (ACTB) as a quality marker of DNA. This method can also be effective in NBS for other severe PID with T- and/or B-cell lymphopenia, including combined immunodeficiency (CID) or agammaglobulinemia. During the 14 months of collaboration, 44,287 newborns were screened according to the ImmunoIVD protocol. Within 65 positive samples, seven were classified to immediate recall and 58 requested a second sample. Examination of the 58 second samples resulted in recalling one newborn. Confirmatory tests included immunophenotyping of lymphocyte subsets with extension to TCR repertoire, lymphoproliferation tests, radiosensitivity tests, maternal engraftment assays, and molecular tests. Final diagnosis included: one case of T-BlowNK+ SCID, one case of atypical Tlow BlowNK+ CID, one case of autosomal recessive agammaglobulinemia, and one case of Nijmegen breakage syndrome. Among four other positive results, three infants presented with T- and/or B-cell lymphopenia due to either the mother's immunosuppression, prematurity, or unknown reasons, which resolved or almost normalized in the first months of life. One newborn was classified as truly false positive. The overall positive predictive value (PPV) for the diagnosis of severe PID was 50.0%. This is the first population screening study that allowed identification of newborns with T and/or B immunodeficiency in Central and Eastern Europe.

SHOULD PERSONNEL OF NUCLEAR MEDICINE DEPARTMENTS USE PERSONAL DOSIMETERS FOR EYE LENS DOSE MONITORING?

Staff at nuclear medicine departments receive doses of ionising radiation higher than the staff of radiotherapy and radiology departments, with the exception of interventional radiologists. Due to the updated lower occupational exposure limit for the lens of the eye, we measured eye exposure in workers of the Nuclear Medicine Department, Pomeranian Medical University in Szczecin, Poland. EYE-D™ dosimeters were used for 3 months by 10 employees working with sources of ionising radiation. Personal dosimeters also measured the exposure of the whole body and hands. The 3-month dose equivalents for the lens of the eye in the employees was 0.20-0.72 mSv. Staff at NMD PMU do not require regular routine eye lens dose monitoring. Eye lens doses were well within the new annual limit of 20 mSv. Doses to the whole body may be used as an indicator of the eye lens doses in the monitored department.

XVI Congress of the Polish Society of Nuclear Medicine. 23-26 May 2018, Szczecin, Poland.

Radioisotope diagnosis and therapy in personalised medicine.

Patient-specific dosimetry of 99mTc-HYNIC-Tyr3-Octreotide in children.

BACKGROUND: Technetium-99m-hydrazinonicotinamide-Tyr3-octreotide (99mTc-HYNIC-TOC) is recognized as a promising radiopharmaceutical for diagnosing neuroendocrine tumors (NETs). However, 99mTc-HYNIC-TOC dosimetry has been investigated only for adults. As pediatric radionuclide therapies become increasingly common, similar dosimetric studies for children are urgently needed. The aim of this study is to report personalized image-based biodistributions and dosimetry evaluations for children studies performed using 99mTc-HYNIC-TOC and to compare them with those from adult subjects. Eleven children/teenage patients with suspected or diagnosed NETs were enrolled. Patient imaging included a series of 2-3 whole-body planar scans and SPECT/CT performed over 2-24 h after the 99mTc-HYNIC-TOC injections. The time-integrated activity coefficients (TIACs) were obtained from the hybrid planar/SPECT technique. Patient-specific doses were calculated using both the voxel-level and the organ-level approaches. Estimated children doses were compared with adults' dosimetry. RESULTS: Pathologic uptake was observed in five patients. TIACs for normal organs with significant uptakes, i.e., kidneys, spleen, and liver, were similar to adults' TIACs. Using the voxel-level approach, the average organ doses for children were 0.024 ± 0.009, 0.032 ± 0.017, and 0.017 ± 0.007 mGy/MBq for the kidneys, spleen, and liver, respectively, which were 30% larger than adults' doses. Similar values were obtained from the organ-level dosimetry when using OLINDA with adapted organ masses. Tumor doses were 0.010-0.024 mGy/MBq. However, cross-organ contributions were much larger in children than in adults, comprising about 15-40% of the total organ/tumor doses. No statistical differences were found between mean doses and dose distributions in patients with and without pathologic uptakes. CONCLUSION: Although the children TIACs were similar to those in adults, their doses were about 30% higher. No significant correlation was found between the children's doses and their ages. However, substantial inter-patient variability in radiotracer uptake, indicating disparity in expression of somatostatin receptor between different patients, emphasizes the importance and necessity of patient-specific dosimetry for clinical studies.

Semi-quantitative method for the assessment of focal lesions in parathyroid scintigraphy with relation to histopathology: a prospective study.

BBACKGROUND: The aim of this paper was to analyse our own semi-quantitative method of assessing focal lesions localised in pre-operative diagnostic scintigraphy of primary hyperparathyroidism (PHPT) using 99mTc-MIBI with washout and comparing these data with the result of the histopathological examination (HP). MATERIAL AND METHODS: A total of 40 (37 female, 3 male, average age 58.7 years) patients with a suspicion of PHPT were enrolled for prospective analysis. Dual phase planar and SPECT/CT examination with 99mTc-MIBI were performed. The tumour to background ratios in the 10th and 120th minute were calculated (TBR10 and TBR120) on the basis of the planar acquisition. PTH, ionised calcium and phosphate levels were measured. Parathyroid surgery alone or combined with subtotal/total thyreoidectomy was conducted in 23 (57.5%) and 17 (42.5%) patients, respectively. A HP was performed in all patients. RESULTS: Average concentration of PTH in the whole group was 243.95 pg/ml. There was a statistically significant correlation between medians of PTH concentration and parathyroid histopathological results (p = 0.01). A total of 45 lesions of increased uptake were found in 32 (80.0%) and 34 (85%) patients in the early phase and the delayed phase, respectively. The post-operative material contained 20 (44.5%) parathyroid adenomas, 11 (24.5%) cases of hyperplasia, 2 (4.4%) cancers, 4 (8.9%) cases of normal parathyroid tissue, 2 (4.4%) lymph nodes and 6 (13.3%) cases of thyroid gland tissue. The medians of TBR10 and TBR120 for lesions examined in the HP were respectively: 3.64 and 2.59 for adenoma; 3.08 and 2.18 for hyperplasia; 7.7 and 5.5 for parathyroid cancer, 4.89 and 3.16 for normal tissue and 5.26 and 2.95 for lymph nodes or thyroid gland tissue. A high correlation coefficient of TBR10 to TBR120 in the parathyroid adenoma and parathyroid hyperplasia groups was observed with r = 0.867 and r = 0.964, respectively. The ρr correlation coefficient of TBR10 to TBR120 for normal parathyroid was 0.4. There was a statistically significant association between the HP and TBR10 medians (p = 0.047), but not between histopathology and TBR120 medians (p = 0.840). CONCLUSIONS: The washout technique in pre-operative 99mTc-MIBI scintigraphy is effective in detecting lesions of the parathyroid (cancer, adenoma, hyperplasia, normal tissue of the parathyroid). Parathyroid cancers in semi-quantitative analysis were characterised by a slightly higher TBR. However, it is impossible to differentiate lesions based on this data. Histopathology results are significantly associated with TBR and PTH.