Hamilton Radiology’s new CT scanner is so quick it’s all over in a heartbeat. Literally.
The machine, installed at the end of last year, can take a full cardiac (heart) scan in the time it takes for the heart to beat once. That opens up a lot of possibilities.
It is the biggest privately owned CT in New Zealand, and represents a massive step up from Hamilton Radiology’s existing scanner.
The new $3 million machine means scanning can be done more quickly and with greater detail, allowing for quicker, more accurate diagnosis and minimising, or in some cases eliminating, the need for invasive procedures.
Since the start of the year, it has been used to scan hundreds of patients at Hamilton Radiology’s Thackeray St premises.
In this case, size matters. The GE Revolution CT can cover a 16 cm area in a single rotation in less than a second. Most other scanners typically have a maximum of 4-8 cm. The new GE Revolution CT scans 512 “slices” per rotation compared with the earlier machine’s 64 slices, and that puts it in company with the very best in the world.
The CT scanner, bought from global company GE, is capable of performing single-beat, motion-free coronary images at any heart rate, says Hamilton Radiology board chairperson Dr Diane Sommerville, who is one of the 18 Hamilton and Rotorua-based specialist radiologists in the practice.
“For patients, it means they will be able to get an accurate diagnosis regardless of their heart rate,” she says.
“For referrers, this gives more patients access to this important test for the diagnosis of coronary artery heart disease.”
“But cardiac is only one of its many uses, and any part of the body can be scanned. Among the range are orthopaedic work, body scans (including CT ‘virtual colonoscopy’ of the bowel) and cancer imaging,” says Dr Sommerville.
The term “CT” stands for computerised tomography. The machines take x-rays from multiple angles at once. The information is fed into a computer which can produce multiple 2D and 3D images of the area being investigated – and if multiple scans are taken over time, then things such as blood flow can also be measured.
One of the gains for patients from the improving technology, including its increased speed, is that more information is available for an equal or lesser radiation dose than was possible in the past.
The greater level of detail also allows for a reduction in invasive or complex and more expensive techniques. If the CT scan shows that the patient’s problem can be dealt with by an adjustment of medication, that can remove the need for surgery altogether.
“We’re hoping that a lot of patients who traditionally didn’t meet the criteria of being able to have a CT scan, and would probably go straight for a more invasive test, like an angiogram or surgery – we’re hoping that we can minimise them having to have the more invasive procedures,” says PET-CT charge Nic Ross.
“And also the enhanced accuracy can reduce the need for return visits for follow-up scans,” Dr Sommerville says.
Apart from the increased width of the scanning detectors and faster scan times, the other major improvement is the ability to use GSI Spectral Imaging.
This allows the scanner to deal with metal, such as hip replacements, which is difficult, if not impossible, for smaller machines. The images they produced could be hard to interpret because the metal would produce distortion – “artefact” is the word used by radiologists. An algorithm in the new software (Spectral Metal Artefact Reduction) accounts for that.
“Before, if somebody had a lot of metal, like a hip or shoulder replacement, a metal plate for a fracture or spinal fixation rods, there was a lot of artefact from that. This meant we couldn’t really interpret the image very well, but now using the spectral programme it’s so much better,” Sommerville says.
“Spectral CT images also allow us to classify things like kidney stones. Now we can say whether the stones are the type that will dissolve with medical treatment (drugs) or if they require surgical treatment, because we can use spectral imaging to tell what the stone is made of.
“Spectral imaging also allows us to provide a world class CT oncology imaging service that is complemented by our other advanced imaging such as PET and MRI.”
Hamilton Radiology prides itself on having stayed at the cutting edge of technology ever since it opened in the 1930s with its first x-ray machine. In more recent years Hamilton Radiology introduced the country’s first 3D ultrasound machine, and in 2011 it installed a PET-CT scanner. Hamilton Radiology is one of just four private centres throughout New Zealand offering a PET-CT service.
PET (Positron Emission Tomography) uses nuclear medicine – injecting the patient with minute doses of radioisotopes – for diagnosis.
A cyclotron, which produces the radioactive material, was established in Wellington in 2010, and more isotopes continue to be developed. The most recent is the PSMA diagnosis for prostate cancer, introduced in the last 12 months, which allows far greater pinpointing of a cancer’s possible spread.
If the prostate gland has developed cancer cells which have moved around, the radiologists can see them since the PET-CT scanner will track the isotope into those areas.
“This has been a bit of a game changer,” says chief executive Philip Hassall, “because quite often it will be the difference between a surgical intervention or another treatment plan”.
Buying the PET-CT machine was a risk that paid off. “Everyone at the time would have thought people will just have to go to Auckland or Wellington,” says Hassall. “We thought Hamilton needed to have its own. We have contracts with the hospitals – when we built it we didn’t have anything.”
As the uses of the scanner increased, Hamilton Radiology needed more capacity – hence the second new, high-specification dedicated CT machine.
All up, the new CT scanner project has cost $3.5 million, with purpose-built rooms added at the Thackeray Street premises. Patients come from as far afield as Hawke’s Bay and Taranaki as well as Waikato, Lakes and Bay of Plenty. Radiologists are always on site to analyse the results, and the team offers same-day reporting to the referring doctor.
Patients will notice benefits beyond just improved diagnostic capability. For instance, the machine’s instructions can be given in one of up to 20 pre-set languages. Completing the futuristic feel, a monitor immediately outside the room allows multiple views for the operating technologist.
“The new CT scanner is a better patient experience. It’s quicker so you’re not there as long, and is more inviting,” says Sommerville.
“The scanner provides the people of the Waikato region with access to one of the most sophisticated CT scanners available in private practice anywhere in New Zealand.”
• Hamilton Radiology has five branches in Hamilton and four other regional offices, offering a range of imaging procedures including general radiography, mammography, and pregnancy and other ultrasounds and ECG.