Pakistan Journal of Nuclear Medicine (PJNM) - Jan 2015 - Volume 05 - Issue 01

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More than 1,000,000 women were diagnosed with breast cancer in the last decade worldwide. The prognosis for this disease improves greatly when it is detected early. Detecting the efficacy of treatments in-vivo can not only expedite the development of drugs but also enable treatments to be more individually tailored. Drugs can induce cell apoptosis and can be a biomarker for monitoring the effectiveness of, for example, chemotherapy. It is preferable to undertake this detection using non-invasive techniques and with non-ionising radiation when possible to minimize discomfort and risks to the patient.

Techniques currently used to diagnose or monitor lesions in the breast often require ionising radiation (e.g. x-ray mammography) or are expensive and time-consuming (e.g. MRI). A number of non-ionising imaging techniques have been investigated for the imaging of the breasts including: near-infrared spectroscopy, electrical impedance spectroscopy and tomography, microwave imaging spectroscopy and photoacoustic and thermoacoustic imaging. Optical imaging can detect suspicious lesions and cell apoptosis, and in some cases can be used as an alternative to imaging using ionising radiation. Optical signals in tissues can however be dependent on a number of factors including vascularity, cellularity, oxygen consumption, water concentration, lipid content, oedema, fibrosis and remodelling.

A key challenge to detecting cancer utilizing light has been the ability to differentiate between absorption and scattering. The breast has a high level of scattering and absorption to optical wavelengths. Most of the important physiological information is contained in the absorption processes. However, scattering processes tend to dominate in breast tissue to the extent that signal requiring propagation over more than just a few millimetres will be dominated by diffusely scattered light. This article reviews recent advances in optical techniques as well as combinations with an advanced molecular imaging method for the early detection of breast cancer and assessing the efficacy of response to therapeutic regime(s).

Aims: This work is intended to establish the effect of ambulatory patients undergoing positron emission tomography (PET) imaging on a sensitive gamma counter that is located within the nuclear medicine department and used for in-vitro tests in the department.

Methods: The effect on gamma counts recorded by a stationary 68Ge positron source and of a PET patient (100 minutes post injection of 550 MBq 18F-2-deoxy-D-glucose) walking past the Perkin Elmer WIZARD2 2470 gamma counter's shielded laboratory was measured. Further tests using uniform 68Ge sources both inside and outside the gamma counter laboratory were performed with a 99mTc glomerular filtration rate gamma counting protocol.

Results: The stationary 68Ge sources could be detected by the gamma counter during both a GFR counting protocol and an open energy window protocol at all distances tested, both inside and outside of the shielded laboratory. A single PET patient walking past the laboratory had a negligible effect on an open counting window.

Conclusions: The potential effects of PET patients on the WIZARD2 gamma counter can be mitigated by ensuring these patients are encouraged to exit the department after their scan without lingering outside the shielded laboratory in the Nuclear Medicine department.

The article referenced as Pak J Nucl Med, 2015;5(1):28-36 has been withdrawn by the publishers on the request of editors.

Aims: The combined application of baseline whole-body bone scan (WBBS), followed by more specific techniques such as SPECT-CT fusion is an advanced approach for the diagnosis, differential diagnosis and staging of osseous metastases. The purpose of this work was to assess SPECT-CT images in diagnosis of suspected bone metastases in patients with oncological diseases.

Methods: This study included 89 patients (54 females, 35 males aged 18-92 yrs) with different types of tumours. All patients underwent routine WBBS with 99mTc-MDP as well as target SPECT-CT imaging using a double-headed SPECT-CT camera coupled with a 2-slice CT scanner.

Results: The skeletal findings with previously uncertain character were classified as definitely benign, indeterminate or definitely malignant. These included: 1) 33% benign degenerative lesions, 2) 28% single osseous metastases, 3) 10% direct bone infiltration, 4) 15% cold or osteolytic bone lesions, 5) 12% mixed type lesions and 6) 2% single extraosseous lesions.

Conclusion: The most important clinical application of bone SPECT-CT imaging is for differential diagnosis between degenerative and metastatic foci with abnormal tracer uptake and similar scintigraphic appearance on the WBBS.

Objective: The study was designed to determine the frequency and patterns of bone metastases in renal and urinary bladder carcinomas on skeletal scintigraphy.

Methods: This retrospective cross sectional study included 76 sequential patients with renal and urinary bladder carcinomas referred for a 99mTc-MDP whole-body bone scan to the Nuclear Medical Centre, AFIP Rawalpindi, from Jan 2011 to Jan 2013. Focal increased radiotracer uptake seen on the bone scans was identified as an osteoblastic or 'hot' lesion, whereas a photon-deficient area was labelled as an osteolytic or 'cold' lesion.

Results Out of 76 patients, renal cell carcinoma was the commonest at 64%, followed by urothelial carcinoma at 27%, transitional cell carcinoma at 5% and clear-cell carcinoma 4%. Three-fourths (75%) of the patients were male and a quarter (25%) female with a mean age of 60 years. 52.6% were negative for skeletal metastases and 47.4% positive. Commonly involved sites in decreasing frequency included the lumbar vertebrae (61%), dorsal vertebrae (25%), the ribs (25%), pelvic bones (22%), sternum (5%), proximal femoral and humeral halves (5%), scapula (2%) and skull (2%). Lytic lesions were present in 11% of the cases.

Conclusion: Skeletal metastases were found in 47.4% of the cases of renal/urinary bladder carcinomas with the lumbar spine being the commonest site involved. In addition to typical 'hot' osteoblastic lesions, 'cold' osteolytic lesions were also present in a small with significant number of cases, which appear deceptive and warrant a meticulous survey of bone scan images in patients with renal and bladder cancers.

Objective: Cisplatin is an effective chemotherapeutic drug for the treatment of solid tumours. However, its nephrotoxic side effects limit its optimal use and renal scintigraphy may be a reliable diagnostic tool for detecting, evaluating, and quantifying any cisplatin-induced nephrotoxicity. This crosssectional retrospective study was designed to determine the frequency of cisplatin-induced severe renal injury by radionuclide renal scintigraphy in patients with solid tumours undergoing chemotherapy with cisplatin-based regimens. The at the Nuclear Medical Centre, Armed Forces Institute of Pathology (AFIP).

Methods: 62 patients (48 male, 14 female) who were candidates for cisplatin-based chemotherapy and had normal renal function as evidenced by normal serum urea and creatinine levels and a normal value of ageadjusted GFR on 99mTc-99m-DTPA renal scintigraphy as per guidelines of National kidney Foundation, were subjected to post chemotherapy 99mTc-DTPA renal scintigraphy within 02 weeks of completion of 06 cycles cisplatin-based chemotherapy.

Results: The frequency of severe renal injury was calculated as 2/62 (3.2%) as determined by 99mTc-DTPA scintigraphy after completion of 6 cycles of chemotherapy

Conclusion: 3.2% of all patients developed severe renal injury at the completion of 6 cycles of cisplatin based chemotherapeutic regimen. This included patients with severe renal injury (GFR 15-29 ml/min) as well as patients with severe renal injury leading to absolute renal failure (GFR < 15 ml/min).

Objective: The study details our work in managing radiation doses to our workers and comforters when dealing with 18F-FDG under the ALARA principle.

Methods: Pakistan's first PET-CT suite with on-site cyclotron was designed under the guidelines of AAPM Task Group Report #108 in 2009. Concrete, Perspex and lead were used as shielding materials to justify cost and space availability. The controlled areas were designed for permissible dose limit of =< 2 microSv/hr. The staff members who have direct contact with 18F-FDG are given thermolumiscence dosimeters to record their monthly wholebody and extremities doses.

Results: Once operational, the maximum prevailing exposure is =< 10 microSv/ hr in FDG Synthesis unit at 5 Ci. The prevailing exposure in the PET-CT Console and injection room is =< 2 microSv/ hr, Prescanning room =< 5 microSv/ hr, post scanning room =< 0.2 microSv/ hr; cyclotron vault surrounding is =< 0.1 microSv/ hr. Nursing staff, injecting and dispensing 18F-FDG are rotated once in a week to inject ten patients per day/week using lead shielding to cover syringe, lead bricks and movable trolley. A short interaction between the patients are the technologists reduces the technologist's dose to =< 0.6 mSv/ month (=< 17 mSv/month). Three radio-chemists produce up to 5 Ci radioactive 18F-FDG on a daily basis in an automated shielded synthesis unit. The average radiation dose for each radiochemist is =< 0.7 mSv/month (=< 27 mSv/month). Medical Physicists and cyclotron engineers receive =< 0.5 mSv/month (=< 10 mSv/month). The comforters receive =< 1.5 mSv/scan recorded by the electronic pocket dosimeter (EPD). Each patient is released when the radiation exposure is reduced to =< 20 microSv/hr at 1 meter.

Conclusion: In the last five years (2009 to 2013), 10,000 patients were scanned with an average of 330 MBq injected dose. The maximum average dose received was 4 mSv/year for some members of nursing staff and radiochemists, whereas the least average dose of 1 mSv/year was received by technologists and the rest of the staff received doses =< 1 mSv/ year.

Hiatus hernia is not an uncommon condition. Its true incidence is difficult to estimate since a proportion of the cases are not demonstrated radiologically, and an equal number of clinical diagnoses are made without radiological demonstration.

We report a case of a 4-year-old boy being investigated for severe anaemia, abdominal pain and maleana who was referred to our institute for a technetium-99m pertechnetate Meckel's scan. The scan revealed a pertechnetate-avid area in the chest. Lateral views of the chest and SPECT images showed this area to be localized to the posterior mediastinum. CT images and barium swallow examination confirmed the diagnosis of hiatus hernia.

Adrenocortical gland carcinoma (ACC) is a rare tumour with an incidence of about one case per million population. Silent ACC are difficult to diagnose as they are asymptomatic until development of mass effects or other related symptoms. We present a case of a silent ACC in a female who was being planned for platinum-based chemotherapy. CT scan showed partial thrombosis of IVC confirmed by Doppler ultrasound. Radionuclide venography (RNV) was used to confirm inferior vena cava (IVC) flow. Blood flow in the IVC was seen to be reduced; however, there were well developed superficial collateral venous channels in the patient. This case shows that RNV is an effective tool for pre-chemotherapy assessment of venous blood flow, which may help in planning on the type of chemotherapy.

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