Executive Summary

Located in Auckland, Ascot Radiology has a varied patient mix, including a large number of orthopaedic and musculoskeletal patients, as well as some spinal and neuro-imaging work. The facility also sees a large number of oncology patients. Cancer is a leading cause of death (approximately 30%) in New Zealand and a major cause of hospitalisation with more than 20,300 people diagnosed with cancer in 2008. (2)  

PET scanning is a recent development in New Zealand. Prior to early 2011 there was no reliable, local supply of FDG isotopes and patients were required to fly to Australia to have this test at significant economic cost and inconvenience. Isotopes were flown across from Australia but many decayed in transit.  

The Facility
Ascot Radiology was established in 1999 at Ascot Integrated Hospital in Green Lane, Auckland, New Zealand. As a specialised radiology clinic offering all diagnostic imaging modalities, it is a leader in the provision of cutting-edge imaging techniques.  

• With ASiR™ (Adaptive Statistical Iterative Reconstruction), CT dose can be reduced up to 40%. (1)
• Time of Flight with VUE Point FX reconstruction – improves signal-to-noise ratio.
• Respiratory Gating – Improves the contrast to noise ratio of moving lesions up to 60% over a static acquisition.


Ascot Radiology had always planned to acquire a PET/CT scanner to assist with more accurate diagnosis of cancer staging and extent of disease spread. As a result, the practice had the necessary space and design to maximise a smooth flow of patients through the centre and reduce their staff’s daily exposure to radiation dose.  

According to principal radiologist, Dr David Rogers, critical factors in the choice of PET/CT scanner were outstanding image quality using reduced dose, Time of Flight imaging capability and breakthrough technologies such as respiratory gating.


The Discovery PET/CT 690™ provides a high image quality. With one of the highest-rated sensitivities in the industry, the scanner is designed to potentially improve cancer detection, enable faster scans and reduce dose requirements. The Discovery PET/ CT 690 aids workflow and patient comfort with unique features like the 70cm wide bore with a full PET and CT field of view, a large patient table and a 2m horizontal scan range for full head-to-toe imaging. Combined, these efficiencies allow patients to finish exams in a timely manner and provide images quickly for physicians to review.  

Lower Dose, High Image Quality
In recent years, there has been a growing proportion of people attending Ascot Radiology, who have expressed concern about radiation dose. The dose reduction solutions offered by the Discovery PET/CT 690 have enabled Ascot Radiology to significantly reduce the amount of radiation their patients are exposed to without compromising image quality or their diagnostic confidence. Further, due to the high sensitivity of the PET component, the radiation dose is further reduced to lower radio isotope dose injection 18F-FDG.  

With ASiR (Adaptive Statistical Iterative Reconstruction), the CT dose can be reduced up to 40% (1) and improve low contrast detectability (LCD) by 30%.  

“We think it is a very useful benefit to be able to offer our patients a PET/CT with the same radiation dose as just a CT scan on a standard scanner. We do all of our imaging on the Discovery PET/CT 690 using ASiR as we have found that the dose levels are much less than what they are when we use a different scanner. When we add in the PET scanner component, the dose is about what we would have normally used in a CT scan before ASiR,” Dr Rogers said.  

“The ASiR feature has also enabled us to see exceptional reductions in metal artefacts. For example, we can now even see the joint between the metal prosthesis and the image is not distorted by the metal. This is a very positive feature.”


Seeing Lesions Without the Movement
The Discovery PET/CT 690 features respiratory gating, which aligns PET and CT gated images to compensate for movement in all regions of the body, particularly those regions subject to respiratory motion. This technology has the potential to improve small lesion detection, image quality and better therapy response monitoring. Respiratory gating helps increase diagnostic confidence and accuracy by addressing motion challenges including artifacts, blurring and quantification.  

“The respiratory gating is a fantastic technology and when you think definitively about it, respiratory gating is necessary for any imaging near the diaphragm because there’s lots of movement,” Dr Rogers said.  

“We recently had a particular patient whose only sign of metastatic disease was a nodule at the base of one lung. It appeared to be a cold nodule that would potentially have been non-malignant. Under normal PET scanning, we couldn’t see this nodule at all however when we performed respiratory gating, the nodule was clearly showing to be hot. The patient subsequently had surgery to remove the nodule and he is now disease free. We got a great outcome for this patient.”  

Time of Flight Increases Diagnostic Confidence
The Discovery PET/CT 690 which features very stable and unique timing resolution, enables High Definition Time of Flight (TOF) image reconstruction (VUE Point FX). TOF is designed to enhance image quality by reducing image artifacts, providing high sensitivity and up to 30 percent improved contrast when compared to non-TOF systems (particularly in large patients). The resulting images help clinicians better detect and locate lesions to increase diagnostic confidence and preserve healthy tissue during treatment.


The Future – Connecting & Saving Lives
According to Dr Rogers, Ascot Radiology is now doing more interventional work as a result of their increased oncology imaging workload. For example, the practice is installing more portacaths for intravenous access for oncology patients who require the administration of chemotherapy.  

The Ascot Radiology team is very interested in supporting research efforts, specifically around the development of pharmaceuticals that offer more specificity for certain tumours and enhance the physician’s view. The Discovery PET/CT 690 has the capability to assist researchers and clinicians who wish to explore the future of molecular imaging, without compromising patient care or image quality.


1. The actual dose reduction level achieved will depend on the application and physician preference with specific protocols.
2. New Zealand Ministry of Health website: http://www.health.govt.nz/
3. Data on file at Ascot Radiology. 


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