Navigation Links
Halving the radiation dose in cardiac perfusion imaging is now 'feasible'
Date:5/17/2011

17 May 2011 -- A reduction by half in the radiation dose to which cardiac patients are exposed during diagnostic perfusion imaging is now "feasible", according to an Israeli study.

Results from the study will be presented as a late-breaking trial at the International Conference of Non-Invasive Cardiovascular Imaging (ICNC) in Amsterdam (15-18 May). ICNC is now one of the world's major scientific events in nuclear cardiology and cardiac CT imaging.

The various modalities of modern perfusion imaging - such as single photon emission computed tomography (SPECT) - allow the non-invasive assessment of myocardial blood flow and thus the detection of coronary artery disease. The cardiac imaging test is usually performed twice to provide a comparison between at rest and at exercise ("rest-stress", and vice-vera). Blood flow can be scanned and visualised because of an injection of radioisotope tracer (technetium sestamibi) which enters through the coronary blood vessels and is distributed into the myocardium ("perfusion"); the images are based on gamma rays given off by the tracer substance. Healthy functional myocardial tissue will absorb the radioactive material. However, in cases of reduced blood flow (because of coronary artery narrowing) perfusion defects will be seen. This denotes "myocardial ischaemia", which occurs following exercise. When there is damaged tissue (infarct), fixed defects will also be seen at rest imaging.

According to Professor Nili Zafrir, Director of Nuclear Cardiology at the Rabin Medical Center in Petah Tikva, Israel, and first author of this late-breaking study, the current application of standard myocardial perfusion diagnosis is "limited" because of "high radiation dose" in the tracer substance with which each patient is injected. She agrees that the radiation dose is within acceptable limits, but insists that the level of radiation exposure (and its consequent cancer risk) is still a matter of great debate. The present study was designed to test whether radiation dose could be reduced without loss of resolution in the diagnostic images.

Radiation effective dose is measured in millisieverts, and, with conventional protocols, each investigation exposes the patient to a radiation dose of between 8 and 25 mSv. This study compared outcome from two protocols, a conventional full dose injection of tracer substance and a half-dose injection. Each group comprised 109 patients, who were investigated with stress-only, rest-and-stress and stress-and rest imaging. The full dose protocol was applied with dosages ranging between 12 and 32 milicurries (mCi) (depending on patient weight); in the half dose protocol dosages ranged between 5 and 17 mSCi. These were converted to radiation effective dose (in mSv).

Professor Zafrir explains that the study only became possible because of the introduction of new image processing software, which was originally designed to reduce the time it takes to acquire a full diagnostic image. " The aim of our study," she says, "was to use the same software but to assess the feasibility of reducing the tracer dose instead of reducing the acquisition time."

Results showed that 94% of the images from the half-dose protocol were assessed as "excellent to good", suggesting no loss of image quality or diagnostic accuracy when the radiation dose of the perfusion was halved.

Professor Zafrir also reports that 35% of the patients in the half-dose group had only a single stress-only investigation, and they were exposed to a mean of just 1.9 mSv. The total effective dose for stress-rest investigation was 7.19 mSv in the half dose protocol compared to 14.4 mSv in the conventional dose protocol.

"So it's our view that myocardial perfusion imaging is feasible with significant radiation dose reduction," says Professor Zafrir. "We found that image quality using the new processing software was similar to that in conventional protocols. Indeed, the clinical results identified with the half-does protocol were equivalent to those determined by full dose imaging. But significantly, the half dose protocol reduced radiation exposure to a minimum of 1.9 mSv in one-third of our patients, far below the dose range we see in conventional perfusion scanning.

"Clearly, we cannot be certain what the long-term benefit of reducing radiation exposure might be, but theoretically it would seem important."


'/>"/>

Contact: Jacqueline Partarrieu
press@escardio.org
33-492-947-756
European Society of Cardiology
Source:Eurekalert

Related medicine news :

1. Thomas Jefferson University and hospitals tasked to find new radiation drugs
2. Low-dose chest CT effective in reducing radiation for evaluation of cardiothoracic surgery patients
3. Study says eliminate pelvic imaging to reduce radiation for the detection of venous thromboembolism
4. Breast Cancer Recurrence Rates Appear Different When Radiation Used
5. Proton imaging provides more accuracy, less radiation to pediatric cancer patients
6. Managing Chemoradiation Side Effects May Prolong Survival
7. Society of Interventional Radiology addresses radiation safety, advances best practices
8. Minimizing side effects from chemoradiation could help brain cancer patients live longer
9. Japanese Radiation Called No Threat to North American Fish Fans
10. Radiation at time of lumpectomy may offer faster, more precise treatment for breast cancer patients
11. New radiation treatment practice recommendations for thyroid disease
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:10/13/2017)... ... October 13, 2017 , ... ... alumni Hannah Randall, PharmD ‘17, and Jennifer Huggins, PharmD ’17, along with ... for the primary prevention of cardiovascular diseases during the 15th Annual Women’s ...
(Date:10/13/2017)... NY (PRWEB) , ... October 13, 2017 , ... Ellevate ... people in business to advocate for action towards gender equality at their inaugural Summit ... from around the globe, and reached a social audience of over 3 million. To ...
(Date:10/13/2017)... ... , ... “The Journey: From the Mountains to the Mission Field”: the story ... the Philippines. “The Journey: From the Mountains to the Mission Field” is the creation ... has taught all ages and currently teaches a class of ladies at her church, ...
(Date:10/12/2017)... ... October 12, 2017 , ... ... meet the demand of today’s consumer and regulatory authorities worldwide. From Children’s to ... and tested to meet the highest standard. , These products are also: ...
(Date:10/12/2017)... ... 12, 2017 , ... Dr. Parsa Mohebi, the Los Angeles ... to the newly revamped Cosmetic Town journal section, featuring articles written ... known as Follicular Unit Extraction (FUE). , Dr. Mohebi says “I ...
Breaking Medicine News(10 mins):
(Date:10/4/2017)... , Oct. 4, 2017 ... single-use, self-contained, illuminating medical devices, today announced regulatory ... Health Surveillance Agency (or Agência Nacional de Vigilância ... first single-use, cordless surgical retractor with integrated LED ... optimal access, illumination and exposure of a tissue ...
(Date:10/2/2017)... , Oct. 2, 2017  AllianceRx Walgreens Prime, the ... by Walgreens and pharmacy benefit manager Prime Therapeutics LLC ... brand, which included the unveiling of new signage at ... as well as at a few other company-owned facilities ... brand to patients, some of whom will begin to ...
(Date:9/28/2017)... , Sept. 28, 2017 Hill-Rom Holdings, Inc. ... earnings conference call and webcast on Friday, November 3, ... (EDT) and ending at approximately 8:30 a.m. (CDT) / ... the company,s 2017 financial performance and guidance for 2018, ... initiatives to enhance operational performance, and long-range financial outlook ...
Breaking Medicine Technology: