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Halving the radiation dosage in cardiac perfusion scan is practicable. New image processing software facilitates for vital radiation dose reduction.

 

These are the findings according to a study was conducted to examine if radiation dosage could be trimmed down, without affecting resolution of medical images. The research was lead by Professor Nili Zafrir, Director of Nuclear Cardiology, Rabin Medical Center in Petah Tikva, Israel.

The results of the study were put forward at the International Conference of Non-Invasive Cardiovascular Imaging (ICNC) in Amsterdam, which is one of the world’s key scientific events in cardiac computed tomography imaging and nuclear cardiology.

 

Of diverse imaging modalities for perfusion scanning – SPECT scans facilitate for non invasive assessment of myocardial blood flow, for detecting coronary artery syndrome.

Cardiac imaging (Cardiology) is generally carried out twice to assess cardiac muscle blood flow on stress and rest conditions, where blood flow is visualized on scan through radioisotope tracers passed by coronary arteries, which is administered in the middle muscular layer of the heart wall (myocardium), where the diagnostic images are established on gamma rays emitted by the tracer substance. The healthy myocardial tissues assimilate radioactive isotopes, but in case of lessened blood flow to cardiac muscles, perfusion defects can be observed. This refers to myocardial ischemia when there is poor balance amongst demand and supply of myocardial oxygen, exists.

Nili Zafrir said, the application of myocardial perfusion imaging is bounded, as due to high radiation dosage in the isotope tracer that the patients are instilled in. Though the radiation dosage is in the satisfactory range, but the level of radiation exposure and cancer risks associated with it is still a prime concern.

With conventional diagnostic imaging techniques, the patient is exposed every time to radiation dosage in the range of 8 and 25 mSv.

The study equated results from two different protocols – half dose injection and conventional full dose injection of isotope tracer. About 109 patients were picked for the study in varied groups that was examined with rest-and-stress, stress-and-rest, and stress-only imaging.

Based on weight of patients, full dose protocol was enforced in with radiation dosage in the range of 12 and 32 mCi. For half dosage protocols, the range was within 5 and 17 mSCi, where these were changed over to effective dose in mSv.

The image processing software that was constructed to trim down the time to acquire diagnostic images made the study easy for Nili Zafrir. The objective of the study was to utilize image processing software, to evaluate the feasibleness of cutting down radioisotope tracer in lieu of abridging accomplishment time.

Consequences of the study demonstrated that about 94% of the medical images from half-dose protocol had highest level of diagnostic precision and image quality when radiation dose of the perfusion fractioned.

Study author even accounts that about 35% of the patients in the half-dose protocol had only stress imaging, where they were exposed to an average of about 1.9 mSv. The overall effective dosage for stress imaging probe was 7.19 mSv in the half dose protocol, in comparison to conventional dose protocol that had 14.4 mSv.

Conclusion: Myocardial perfusion imaging is practicable with vital radiation dosage reduction. Half dose protocol trimmed down radiation exposure to 1.9 mSv in majority of patients, below than that of range in conventional perfusion imaging. Imaging quality of new processing software showed same image quality, as that of conventional protocol – the clinical results were equivalent to that identified by full dose imaging.

Recent study reveals that, the use of physiological and structural images taken from SPECT/CT hybrid imaging can help better diagnose and treat renal-transplant related issues.

Kidney transplant could mean a blessing with no dialysis for more than 15,000 Americans every year. However,complications post surgery are also a common issue. The traditional physican use of two-dimensional planar imaging to evaluate post-renal transplant complications included urinary leak, infection and transplant non-viability or kidney failure.

The study presented at SNM’s 57th Annual Meeting by the Cleveland Clinic. SPECT and CT imaging techniques were compiled to produce a detailed picture of the process of renal functions. The research results showed that three-dimensional SPECT/CT hybrid imaging is best-suited for similar and other disease states. Engaging SPECT/CT imaging may even prevent further imaging studies or invasive biopsies. Thus, avoiding delayed patient care.

About 12 renal transplant cases were involved in the study. Out of those, 10 patients were suspected of urinary leak, one with kidney failure and the other was suspected of experiencing a transplant-associated infections. All patients underwent scan post conventional planar imaging, with non-circular SPECT imaging and low dose non-contrast CT imaging using a hybrid SPECT/CT system. The SPECT/CT usage with Tc99m-MAG3, which is an imaging agent taken up by the kidneys and utilized for detection of renal function, assisted physicians positively diagnose urinary leaks for 70% of the patients when fused imaging exposed fluid outside The anatomical confines of the patients’ urinary system. Similar agent molecular imaging technique also succeeded in recognising kidney failures. The patient injected with In-111 labeled WBC, an agent that helps image leukocyte activity associated with the body’s immune response helped detect infection.

According to Shashi Khandekar, administrator of the nuclear medicine department, Cleveland Clinic, Cleveland, Ohio. “SPECT and CT fused images provide both functional and anatomical information about the kidney, which provides better diagnostic capability and greater confidence to our physicians.”