Health Policy Advisory Committee on Technology

Health Policy Advisory Committee on Technology Technology Brief PET MRI integrated hybrid scanners February 2012

State of Queensland (Queensland Health) 2012 This work is licensed under a Creative Commons Attribution Non Commercial No Derivatives 2.5 Australia licence. In essence, you are free to copy and communicate the work in its current form for non commercial purposes, as long as you attribute the authors and abide by the licence terms. You may not alter or adapt the work in any way. To view a copy of this licence, visit http://creativecommons.org/licenses/by nc nd/2.5/au/. For further information, contact the HealthPACT Secretariat at: HealthPACT Secretariat c/o Access Improvement Service, Centre for Healthcare Improvement, Queensland Health Lobby 2, Level 2, Citilink Business Centre 153 Campbell Street, Bowen Hills QLD 4006 Postal Address: GPO Box 48, Brisbane Qld 4001 Email: HealthPACT@health.qld.gov.au Telephone: (07). 3131 6969 For permissions beyond the scope of this licence contact: Intellectual Property Officer, Queensland Health, GPO Box 48, Brisbane Qld 4001, email ip_officer@health.qld.gov.au, phone (07) 3234 1479. Electronic copies can be obtained from: www.health.qld.gov.au/healthpact DISCLAIMER: This brief is published with the intention of providing information of interest. It is based on information available at the time of research and cannot be expected to cover any developments arising from subsequent improvements to health technologies. This brief is based on a limited literature search and is not a definitive statement on the safety, effectiveness or costeffectiveness of the health technology covered. The State of Queensland acting through Queensland Health ( Queensland Health ) does not guarantee the accuracy, currency or completeness of the information in this brief. Information may contain or summarise the views of others, and not necessarily reflect the views of Queensland Health. This brief is not intended to be used as medical advice and it is not intended to be used to diagnose, treat, cure or prevent any disease, nor should it be used for therapeutic purposes or as a substitute for a health professional's advice. It must not be relied upon without verification from authoritative sources. Queensland Health does not accept any liability, including for any injury, loss or damage, incurred by use of or reliance on the information. This brief was commissioned by Queensland Health, in its role as the Secretariat of the Health Policy Advisory Committee on Technology (HealthPACT). The production of this brief was overseen by HealthPACT. HealthPACT comprises representatives from health departments in all States and Territories, the Australian and New Zealand governments and MSAC. It is a subcommittee of the Australian Health Ministers Advisory Council (AHMAC), reporting to AHMAC s Hospital Principal Committee (HPC). AHMAC supports HealthPACT through funding. This brief was prepared by Linda Mundy from the HealthPACT Secretariat.

TECHNOLOGY BRIEF REGISTER ID WP026 NAME OF TECHNOLOGY PET MRI FULLY INTEGRATED HYBRID SCANNER PURPOSE AND TARGET GROUP FOR THE FUNCTIONAL ASSESSMENT OF CANCER STAGE OF DEVELOPMENT IN AUSTRALIA Yet to emerge Established Experimental Established but changed indication or modification of technique Investigational Should be taken out of use Nearly established AUSTRALIAN THERAPEUTIC GOODS ADMINISTRATION APPROVAL Yes ARTG number Siemens Ltd PET/MRI system ARTG number: 188470 Registered: 24/08/2011 Philips Electronics Australia Ltd PET/MRI system ARTG number: 193622 Registered: 7/01/2012 No Not applicable INTERNATIONAL UTILISATION COUNTRY Germany Switzerland United States Trials underway or completed LEVEL OF USE Limited use Widely diffused IMPACT SUMMARY Two companies manufacture PET MRI 1 systems with the aim of providing the registration and fusion of functional PET images and MR anatomical information that are acquired in the same scanner session. InSight Oceania Pty Ltd distributes the PET MRI integrated hybrid scanners: February 2012 1

Ingenuity TF PET/MRI scanner manufactured by Philips Electronics Australia Ltd. Siemens Ltd manufactures and distributes the Biograph mmr system. Both systems hold the CE mark and are FDA approved. The integrated systems maintain the independent functionality of the MR and PET imaging devices, allowing for single modality MR and / or PET imaging. GE Healthcare also markets a PET MRI system, however, this system is not fully integrated and requires the patient to be transported from one modality (PET CT) to the other (MRI). Although these systems are intended to be used to assist in the detection, localisation and diagnosis of conditions in the oncology, neurology and cardiology fields, it is likely that their main function will be the functional assessment of cancer, in particular cancer of the head and neck, brain and prostate. BACKGROUND Prior to the development of hybrid imaging systems, fusion images were achieved post hoc by overlapping images from separate imaging modalities (eg CT and PET), initially by eye and then by using specialised software. Image overlapping was successful for fixed organs such as the brain but not for internal abdominal organs, which could move independently between scans. Fusion imaging has been described as time consuming and errors may occur due to patient movement or discrepancies in patient position between scans. To overcome these technical difficulties, a scanner that combines both PET and CT technologies was developed to accurately acquire aligned anatomical and functional images in the same scanning session (Beyer et al 2000; Townsend & Beyer 2002). Hybrid imaging systems were first developed in the late 1990s with the introduction of the combined PET CT housed in a single gantry. In combined PET CT systems, the CT data reveals anatomical information about the patient, whereas PET provides predominantly functional and metabolic information. In addition, CT data can be used to calculate the attenuation correction for the PET scan (Schoder et al 2003). Only sequential rather than simultaneous image acquisition is possible with PET CT systems and involuntary patient motion from respiration or cardiac motion may result in the misalignment of images that may translate into artefacts on the PET images. Of importance, however, is consideration of the ionising radiation dose received by patients undergoing combined PET CT imaging, which may limit the ability to perform repeat scans in some patients. It is estimated that patients undergoing a combined PET CT scan will receive an overall dose between 20 25 msieverts per examination, consisting of the radiation dose from the CT and the approximate 370 MBq of 18 FDG 2 (Beyer et al 1 PET = positron emission tomography, MRI = magnetic resonance imaging, CT = computed tomography 2 Sievert = an SI unit for the dosage of ionising radiation, 18 FDG = the radionucleotide 2-[ 18 F] fluoro-2- deoxy-d-glucose, MBq = mega becquerel, 10 6 Bq, which is the SI unit of radioactivity PET MRI integrated hybrid scanners: February 2012 2

2010). It should be noted that clinical opinion has advised that with recent changes in CT reconstruction technology, that the radiation dose associated with a PET CT scan will be reduced and that not all patients will require a full diagnostic CT. The inability to provide anatomical information is a limiting factor in clinical use of PET. Therefore, to maximise the potential of PET, anatomical images are often acquired using CT or MRI, with many patients undergoing a diagnostic work up consisting of a PET CT scan followed by MRI imaging. This trend led to the development of hybrid PET MRI systems. MRI offers superior soft tissue imaging compared to CT with the additional benefit of not exposing the patient to ionising radiation, which may be of particular importance in paediatric oncology. In addition to enhanced morphological and anatomical imaging with or without contrast agents, MRI offers the ability to perform functional studies using diffusion weighted MRI (Beyer et al 2010). In oncology, imaging with PET provides clinicians with functional information in regard to the metabolism or physiology of the tumour, especially in respect to the assessment of lymph nodes. Due to the inherent metabolic and receptor specific uptake of the tracer, PET is not capable of accurately assessing the local extent of the primary tissue in some locations such as head and neck, however, this information may be gained with the use of MRI imaging. The disadvantages of using MRI that also need to be considered include a longer examination time compared to CT, patients with metal implants and pacemakers are contraindicated, MRI is more expensive to perform than CT and the number of patients unable to undergo a scan due to claustrophobia is higher for MRI than CT (Antoch & Bockisch 2009; Ratib & Beyer 2011). Combining two imaging modalities such as PET and MRI presents some unique challenges, foremost being that the traditional photomultiplier tubes used in PET scanners are highly sensitive to magnetic fields and are not functional in an MRI environment. This requirement led to the development of detectors and photodiodes capable of detecting the signals (scintillation light) from the PET whilst being in a strong magnetic field (Quick et al 2011). PET MRI systems require a slightly larger physical environment than clinical 3T MRI systems. The MRI environment is considered sufficient for the radiation protection of the PET patient, however this would need to be certified by the appropriate authority. Unlike a standard MRI facility, the hybrid scanning suite would require appropriate facilities for workflow with a radioactive patient population, entailing a segregated injection room, uptake room and an associated hot lab (personal communication InSight Oceania Pty Ltd). PET MRI integrated hybrid scanners: February 2012 3

It has been estimated that a diagnostic PET MRI study could be completed within an hour 3, which is longer than the time required for a PET CT study but considerably less time than the time required for a PET CT scan followed by an MRI study performed on two different systems (Ratib & Beyer 2011). The Siemens Biograph mmr is the only truly integrated PET MRI system capable of taking simultaneous images currently available. The Biograph mmr consists of a dedicated whole body PET scanner built into a dedicated 3T MRI scanner (Figure 1). The fusion image software, syngo.via, can be used for the hybrid PET MRI or for images acquired via stand alone imaging modalities. Due to its integrated nature, the Biograph does not require any more room than a conventional MRI. The Biograph mmr may be used as a standalone MRI scanner (Siemens AG 2010). Figure 1 a) Schematic drawing showing the integration of the PET detectors in the MR hardware structure of the Biograph mmr and b) a photograph of the Biograph mmr (Quick et al 2011) The Philips Ingenuity TF PET MRI combines two separate gantries in a tandem configuration, where the two examinations are performed. A 3T multi transmit MRI and a high resolution Time of Flight PET are connected by a patient turntable that conveys the patient from one examination to the next without requiring them to move from the table (Figure 2). All PET and MR applications that are available on standalone systems are available on the hybrid PET MR. The data from the two scanners are inherently fused at hardware level (personal communication InSight Oceania Pty Ltd). 3 A whole-body PET/MR scan can be completed in 20min, the extra overhead is related to the localised MR sequences that the radiologist will prescribe (personal communication Philips) PET MRI integrated hybrid scanners: February 2012 4

PET component MRI component Patient turntable Figure 2 The Philips Ingenuity TF PET/MRI scanner (printed with permission) Hybrid scanners such as PET CT systems are able to obtain Medicare Benefits Schedule rebates under the current Medicare system and there would be no impediment to hybrid PET MRI systems claiming a MBS rebate. However, under current arrangements, in order for an MRI scan to attract a Medicare rebate, it must be: an item listed on the Medical Benefits Schedule (MBS); requested by a specialist medical practitioner or consultant physician; and performed on a Medicare eligible MRI unit located within a comprehensive medical imaging facility, offering x ray, computed tomography and ultrasound services (personal communication InSight Oceania Pty Ltd). In the 2011 12 Budget, the Australian Government announced that $104.4 million will be provided over four years to implement the Diagnostic Imaging Review Reform Package. The aim of this package is to ensure ongoing, affordable, and convenient diagnostic imaging services for patients, with a focus on the staged expansion of patient access to Medicare eligible MRI services for existing Medicare ineligible MRIs. This staged expansion is due to commence from May 2012 (DoHA 2011). For new MRI or PET/MRI machines, there is currently no process for obtaining Medicare eligibility. Operators of PET MRI systems will be nuclear medicine technologists who are qualified in the use of clinical MRI, or radiographers who are qualified to operate a PET scanner. It is likely that these systems will be used by a combination of operators with the diagnostic interpretation of images conducted by either dual qualified PET MRI integrated hybrid scanners: February 2012 5

radiologists or by an MR specialist radiologist in conjunction with a qualified PET physician (personal communication InSight Oceania Pty Ltd). CLINICAL NEED AND BURDEN OF DISEASE Although integrated PET MRI systems may potentially be used for a number of indications (oncology, neurology and cardiology), it is expected that its primary function will be the functional assessment of cancer, in particular those cancers that are difficult to assess using CT, such as head and neck, brain and prostate cancer. Data for the clinical burden of disease for these cancers are summarised in Table 1. Table 1 Burden of disease for prostate, brain, head and neck cancer in Australia and New Zealand Cancer Incidence: number of cases ASR per 100,000 Mortality: number of cases ASR per 100,000 Australia 2007 data Prostate 19,403 182.9 2,938 31.0 Brain 1,472 6.7 1,123 5.1 Head and neck* 2,672 12.5 889 4.2 New Zealand 2008 data Prostate 2,939 103.3 670 9.3 Brain 244 4.7 207 3.6 Head and neck n/a n/a n/a n/a * 2005 data, n/a = not available, ASR = age-standardised incidence rate (AIHW & AACR 2010, AIHW 2008, NZ MoH 2011) As stated above, PET MRI may be of particular use in paediatric oncology due to the reduced radiation dose delivered to the patient compared to PET CT. Data from the AIHW s cancer incidence data cube 4 indicates that the number of paediatric patients with cancer has remained relatively steady in recent years. In 2007 there a total of 299 cases of cancer in patients aged 0 4 years, 137 and 164 cases in those aged 5 9 and 10 14 years, respectively. For the same age groups in the year 2008 there were 289, 123 and 178 cases, respectively. In 2008, a large proportion of cases in all age brackets were for the principle diagnosis of lymphoid (C91) or myeloid (C92) leukaemia, diagnosis of which would not be assisted by PET MRI imaging: 0 14 years = 38.1 per cent, 5.9 years = 36.6 per cent and 10 14 years = 28.1 per cent. Those cancers with the highest case numbers that may benefit from the use of PET MRI are summarised in Table 2. 4 http://www.aihw.gov.au/cancer-data-cube PET MRI integrated hybrid scanners: February 2012 6

Table 2 Cancers with high case numbers in Australian paediatric patients, 2008 Cancer Total number of cases Cases Percentage of total 0-14 years 289 C22 Liver 10 3.4 C64 Kidney 21 7.3 C69 Eye 22 7.6 C71 Brain 32 11.1 C74 Adrenal Gland 26 9.0 5-9 years 123 C71 Brain 24 19.5 10-14 years 178 C40 Bone 13 7.3 C71 Brain 26 14.6 DIFFUSION OF TECHNOLOGY IN AUSTRALIA To date, Philips Medical Systems have sold 17 Ingenuity TF PET/MRI scanner systems worldwide. As of September 2011, five of these systems have been installed and it is expected that at least 7 8 of the systems will have been installed and functional at the beginning of 2012. The demand for PET/MRI systems is increasing and Philips envisages filling approximately 80 orders worldwide in the coming year. In Australia, InSight Oceania Pty Ltd is currently in discussions with over eight centres in regard to purchasing the PET/MRI technology, and it is estimated that at least 50 per cent of these centres are funded for the purchase of a system within the next 18 months (personal communication InSight Oceania Pty Ltd). Due to the newness of the technology, there are currently no Biograph systems installed to date in Australia, however 20 orders have been placed to purchase this technology worldwide (personal communication Siemens Ltd. Australia & New Zealand). COMPARATORS The comparators for a hybrid PET MRI system would be a combination of stand alone imaging modalities, such as PET, CT and MRI, or as described above, a hybrid PET CT scanner. Images would be obtained from these stand alone systems that are likely to be in physically different locations. These images would be taken at different time points then co registered and fused together using specialised software. The resulting images are prone to error due to patient movement or discrepancies in patient position between scans. PET MRI integrated hybrid scanners: February 2012 7

SAFETY AND EFFECTIVENESS One of the first clinical experiences using a prototype of the Philips hybrid PET MRI was described by Ratib et al in an abstract presented at the 2011 conference of the International Society for Magnetic Resonance in Medicine. The prototype consisted of a tandem arrangement of a GEMINI TF PET scanner and an Achieva 3T X series MRI which were separated by approximately three metres at either end of a patient bed that allowed a 180 rotation. Oncology patients scheduled for a routine PET CT scan were randomly selected to undergo an additional PET MRI. A number of diagnoses were present in the 64 patients included in the study: breast cancer (n=11), lung cancer (n=4), lymphoma (n=6), head and neck cancer (n=8), prostate cancer (n=13), sarcoma (n=5), melanoma (n=2), gastrointestinal tumours (n=5) with the remaining seven patients scanned as a follow up to treatment (level III 2 diagnostic evidence). All patients underwent a PET CT scan 60 minutes following the injection of 361 ± 32 MBq of 18 F FDG. Patients were then immediately transferred to the PET MRI scanner without the need for an additional tracer injection. The average time between the PET CT and PET MRI scans was 85 ± 22 minutes (range 49 120 minutes). Patients first underwent an MRI attenuation correction scan, which took three minutes, before being moved into position for the PET scan, which had a total acquisition time of 18 20 minutes. Patients were then moved back to the MRI for diagnostic imaging relevant to their clinical indication. Images were then reviewed and reconstructed by tandems of radiologists and nuclear physicians and compared to those obtained in the PET CT study. PET MRI images were as accurate as PET CT images for the detection and localisation of focal lesions and tumours. MRI scans obtained for attenuation correction did not provide sufficient resolution compared to the CT images taken for the same reason. Additional MR sequences were required for the adequate anatomical localisation and characterisation of focal PET lesions. The PET images obtained with the PET MRI were comparable to those obtained with the PET CT (Ratib et al 2011). Ten patients with intracranial masses took part in a pilot study that compared clinically indicated images obtained with a brain PET CT scan to those obtained with a prototype hybrid PET MRI scanner (level III 2 diagnostic evidence). The hybrid consisted of an MRI compatible PET system (BrainPET, Siemens) inserted into a modified 3T MRI (Magnetom Tim Trio, Siemens). Seven patients were diagnosed with glial tumours and three with meningioma (median age of patient group 51 years, range 34 73). PET MRI integrated hybrid scanners: February 2012 8

Patients with glial tumours underwent PET CT 30 minutes after injection with 11Cmethionine (585 764 MBq) and data acquisition lasted for eight minutes. The three meningioma patients were injected with 126 153 MBq of 68Ga DOTATOC 5 with data acquisition commencing 20 minutes after and lasting for four minutes. Attenuation correction was achieved via a non contrast CT scan in the glioma patients and a contrast CT scan in the meningioma patients. Attenuation corrected transaxial slices were reconstructed using the standard scanner software. Simultaneous PET MRI data acquisition began 30 60 minutes after the PET CT scan. Tumour to grey matter (T:G) and tumour to white matter (T:W) ratios were calculated using a region of interest analysis for both hybrid screening modalities for the glioma patients using (Table 3). For the meningioma patients the uptake in tumour tissue to uptake in nasal mucosa (T:NM) was calculated (Table 4). Comparable ratios were achieved with both modalities. The mean paired differences were 0.14 ± 0.30 for T:G and T:NM ratios (relative difference (RD) 7.9 ± 12.2%), 0.25 ± 0.19 for T:G ratios alone (RD 12.7 ± 7.0%), 0.07 ± 0.23 for T:W ratios (RD 3.4 ± 7.5%) and 0.15 ± 0.16 for G:W ratios (RD 9.4 ± 9.7%). The mean G:W ratio was 1.51 ± 0.08 for PET MRI and 1.67 ± 0.12 for PET CT. The correlation of T:G and T:NM ratios of PET CT and PET MRI was excellent with a Pearson correlation coefficient of 0.98 (R2 = 0.96). The correlation coefficient of PET CT and PET MRI was 0.99 for both T:G and T:W ratios alone. In addition, no significant artefacts were detected in the MR images acquired via the hybrid scanner (Boss et al 2010). Table 3 Tumour uptake ratios in comparison to reference regions in glioma patients (Boss et al 2010) Patient number T:G ratio T:W ratio G:W ratio PET-CT PET-MRI PET-CT PET-MRI PET-CT PET-MRI 1 1.76 ± 0.69 2.04 ± 0.99 3.08 ± 1.38 2.88 ± 0.50 1.74 ± 0.76 1.41 ± 0.74 2 2.93 ± 0.71 3.34 ± 1.09 5.51 ± 1.33 5.28 ± 1.73 1.88 ± 0.49 1.58 ± 0.59 3 0.88 ± 0.26 1.0 ± 0.26 1.42 ± 0.44 1.40 ± 0.41 1.61 ± 0.49 1.40 ± 0.42 4 2.25 ± 0.47 2.70 ± 0.67 3.83 ± 0.22 4.10 ± 1.03 1.70 ± 0.42 1.52 ± 0.45 5 1.88 ± 0.42 2.30 ± 0.64 3.13 ± 0.71 3.55 ± 1.22 1.67 ± 0.38 1.54 ± 0.41 6 1.29 ± 1.89 1.26 ± 0.40 1.89 ± 0.43 2.01 ± 0.59 1.47 ± 2.09 1.59 ± 0.46 7 0.70 ± 0.18 0.80 ± 0.41 1.14 ± 0.31 1.27 ± 0.66 1.62 ± 0.39 1.59 ± 0.69 T:G = Tumour-to-grey matter ratio, T:W = Tumour-to-white matter ratio, G:W = grey matter to white matter ratio 5 68 Ga-DOTATOC = DOTA-d-Phe(1)-Tyr(3)-octreotide: binds specifically to somatostatin receptors which are over-expressed in meningiomas PET MRI integrated hybrid scanners: February 2012 9

Table 4 Tumour uptake ratios in comparison to reference regions in meningioma patients (Boss et al 2010) Patient number T:NM ratio Volume (cm 3 ) PET-CT PET-MRI PET-CT PET-MRI 8 1.55 ± 0.46 1.32 ± 0.21 0.2 0.2 9 5.62 ± 1.55 5.20 ± 2.83 20.5 22.6 10 2.12 ± 0.80 2.43 ± 0.94 5.1 5.0 T:NM = uptake in tumour tissue to uptake in nasal mucosa Another small pilot study by the same author, used the same hybrid PET MRI system described above to image eight patients (median age 65.5 years, range 42 82) with head and neck cancer, compared to PET CT imaging (level III 2 diagnostic evidence). All patients underwent a whole body and head and neck PET CT scan 60 minutes after injection with 18 FDG. The initial attenuation correction CT scan was conducted after injection of a contrast agent and was followed by PET data acquisition (3 minutes per bed for body imaging and 4 minutes for the head and neck imaging). PET MRI imaging began 30 to 60 minutes after completion of the PET CT scan. PET data were acquired for 25 minutes, which was longer than during PET CT imaging. This longer acquisition time was due to the simultaneous MRI/PET data acquisition and is therefore governed by time required for MRI imaging. Image analysis was performed using the VINCI software. Regions of interest were drawn on the PET CT images over regular anatomical structures with known FDG uptake and were then copied to the co registered PET MRI images. The radionuclide uptake of the defined anatomical regions was quantified in relation to mean cerebellum uptake and expressed as mean and maximum metabolic ratios (Table 5). There were no visible artefacts on the MRI images caused by the insertion of the PET system. In addition, the PET images acquired during PET MRI imaging were of better quality than those obtained during PET CT imaging, with increased resolution and greater image contrast. There was excellent correlation between the averaged PET MRI and PET CT values (R = 0.99). For the mean and maximum metabolic ratios the correlation coefficients were R = 0.92 and R = 0.96, respectively, for the maximum metabolic ratios (Boss et al 2011). PET MRI integrated hybrid scanners: February 2012 10

Table 5 Mean metabolic ratios of soft tissue structures of the head and neck (Boss et al 2011) Tissue PET-CT PET-MRI Literature values Base of tongue, lingual tonsil 0.411 ± 0.16 0.411 ± 0.179 0.400 Gingiva 0.362 ± 0.186 0.347 ± 0.136 0.30 0.35 Nasopharynx, adenoids 0.416 ± 0.151 0.322 ± 0.100 0.40 0.49 Palatine tonsil 0.737 ± 0.350 0.626 ±0.301 0.55 0.72 Parotid gland 0.239 ± 0.079 0.268 ± 0.080 0.30 0.32 Sublingual gland 0.547 ± 0.187 0.544 ± 0.226 0.39 -.056 Turbinates 0.233 ± 0.128 0.241 ± 0.089 0.34 COST IMPACT The estimated cost of the Siemens Biograph is 4.7m, however this figure will depend on infrastructure requirements and will likely decrease in time with increased adoption of the technology (personal communication Siemens Ltd. Australia & New Zealand). The cost of the Philips Ingenuity TF is unknown at date of publication but would be dependent on the site configuration and the actual clinical requirements of the site. These requirements may include advanced high level MR applications with dedicated coils for clinical and research purposes and/or PET components such as the next generation of time of flight (TOF) with a high speed reconstruction computer. Any cost effectiveness analysis would need to consider the cost offsets gained from faster imaging with PET MRI compared to imaging with stand alone scanners or hybrid PET CT, in addition to considering the estimated lifespan of the PET MRI device. A cost analysis would also need to consider that the use of MRI requires a longer examination time, which may impact on patient flow, and is more expensive to perform compared to CT (Antoch & Bockisch 2009; Ratib & Beyer 2011). PET MRI systems require both nuclear medicine technologists and radiographers, both operationally and for the reading and interpretation of images. Therefore it is likely that the implementation of this technology will increase costs due to its impact on the workforce in terms of training and increasing the number of skilled operators in the existing workforce. ETHICAL, CULTURAL OR RELIGIOUS CONSIDERATIONS No issues were identified. OTHER ISSUES Clinician feedback has indicated that the image quality of the PET component of the mmr is not as good as a standalone, current state of the art Siemens PET scanners, PET MRI integrated hybrid scanners: February 2012 11

as the photodiodes do not have sufficient timing resolution to allow time of flight reconstructions, which improve image quality, especially in larger patients. Clinically, the diagnostic performance of the two modalities in combination is currently not as effective as the standalone modalities. It is likely that PET MRI will only be offered in large tertiary hospitals situated in major population centres which would require patients from rural and remote areas to travel to access this technology. The International Society for Magnetic Resonance in Medicine conference is to be held in Melbourne 5 11 May 2012. There is likely to be a strong focus on PET MRI at this conference. SUMMARY OF FINDINGS There are few clinical studies in the literature reporting on the use of hybrid PET MRI systems, and none to date that report on the use of the two systems described in this brief. Initial, small scale studies indicate that PET MRI hybrid scanning systems are as effective at imaging regions of interest in certain brain cancers and head and neck cancer as PET CT hybrid scanners, however these imaging studies do not indicate the effect on clinical outcomes for these patients or a change in patient management. PET MRI scanners represent a large infrastructure investment, and as such would require evidence of clinical effectiveness gathered from studies conducted on larger patient groups. HEALTHPACT ASSESSMENT Based on the small number of published studies it appears that hybrid PET MRI may be a promising imaging modality, especially for paediatric patients, with the added benefit of reduced exposure to radiation compared to a PET CT scan. It should be noted, however, that recent developments in CT design have resulted in scanners that deliver a reduced radiation dose. In addition, combined PET MRI systems are not capable of producing as high quality images as standalone imaging systems. It would appear that the combined PET MRI systems are currently of benefit in the research, rather than clinical setting. Larger studies with clinical outcomes are required to demonstrate the effectiveness of the modality. HealthPACT note the concerns of clinicians and jurisdictions regarding the paucity of evidence in respect to the clinical effectiveness of hybrid PET MRI scanners and the potential for increased costs due to workforce issues including training requirements, time taken for interpretation of images, increasing IT capacity for image storage and the impact on patient flow. Since the completion of this brief PET MRI systems have been purchased for use within Australian public hospitals. HealthPACT recommend that PET MRI integrated hybrid scanners: February 2012 12

sensitivity and specificity data on systems about to be installed in Australia be collected to inform an analysis of clinical efficacy and cost effectiveness. NUMBER OF STUDIES INCLUDED All evidence included for assessment in this Technology Brief has been assessed according to the revised NHMRC levels of evidence. A document summarising these levels may be accessed via the following link on the HealthPACT web site. Total number of studies 3 Total number of Level III 2 diagnostic evidence studies 3 REFERENCES AIHW (2008). Cancer in Australia: an overview, 2008 [Internet]. Australian Institute of Health and Welfare. Available from: http://www.aihw.gov.au/publications/index.cfm/title/10607 [Accessed 30 September 2010]. AIHW & AACR (2010). Cancer in Australia: an overview, 2010, Australian Institute of Health and Welfare & Australasian Association of Cancer Registries Canberra. Antoch, G. & Bockisch, A. (2009). 'Combined PET/MRI: a new dimension in wholebody oncology imaging?', Eur J Nucl Med Mol Imaging, 36 Suppl 1, S113 120. Beyer, T., Schwenzer, N. et al (2010) In MAGNETOM Flash, Vol. 3 Siemens. Beyer, T., Townsend, D. W. et al (2000). 'A combined PET/CT scanner for clinical oncology', J Nucl Med, 41 (8), 1369 1379. Boss, A., Bisdas, S. et al (2010). 'Hybrid PET/MRI of intracranial masses: initial experiences and comparison to PET/CT', J Nucl Med, 51 (8), 1198 1205. Boss, A., Stegger, L. et al (2011). 'Feasibility of simultaneous PET/MR imaging in the head and upper neck area', Eur Radiol, 21 (7), 1439 1446. DoHA (2011). Diagnostic Imaging Review Reform Package: Magnetic Resonance Imaging (MRI) [Internet]. Australian Government Department of Health and Ageing. Available from: http://www.health.gov.au/internet/main/publishing.nsf/content/20def6b7956a92 70CA25757D001015FF/$File/MRI%20Info%20 %20May%2011.pdf [Accessed 11th January]. NZ MoH (2011). Cancer: New registrations and deaths 2008, New Zealand Ministry of Health, Wellington. Quick, H. H., Ladebeck, R. & Georgi, J. C. (2011) In MAGNETOM Flash, Vol. 1 Siemens, pp. 88 100. Ratib, O. & Beyer, T. (2011). 'Whole body hybrid PET/MRI: ready for clinical use?', Eur J Nucl Med Mol Imaging, 38 (6), 992 995. Ratib, O., Viallon, M. et al (2011) In International Society for Magnetic Resonance in Medicine, Vol. 19 Proc. Intl. Soc. Mag. Reson. Med, Montreal, Canada, pp. 761. Schoder, H., Erdi, Y. E. et al (2003). 'PET/CT: A new imaging technology in nuclear medicine', European Journal of Nuclear Medicine and Molecular Imaging, 30 (10), 1419 1437. PET MRI integrated hybrid scanners: February 2012 13

Siemens AG (2010). For the first time, MR and PET are one [Internet]. Available from: http://www.medical.siemens.com/siemens/en_gb/gg_mr_fbas/files/brochures/bio graph_mmr brochures/101026_ws_biograph_mmr_int.pdf [Accessed 9th January]. Townsend, D. W. & Beyer, T. (2002). 'A combined PET/CT scanner: The path to true image fusion', British Journal of Radiology, 75 (SPEC. ISS.), S24 S30. SEARCH CRITERIA TO BE USED Humans Magnetic Resonance Imaging/*methods Positron Emission Tomography/*methods Whole Body Imaging/*methods Image Processing, Computer Assisted Neoplasms/*diagnosis/pathology/radiography/radionuclide imaging PET MRI integrated hybrid scanners: February 2012 14