Line 810:“Recently a system has been proposed and built that covers a full body length of 2 m (Badawi et al., 2019). Since a major part of the price of a system scales with length, systems like that most likely will remain instruments for research and special application, e.g. ”
A 2-meter device has been FDA certified and successfully deployed in clinical practice, not limited to the research field. Practice has shown that its outstanding performance can greatly assist in imaging diagnosis.It may become an important PET/CT device in the future[1].
Line 851:“The value zero represents air, 1000 is pure water, and bone (from spongious to compact) typically will be represented in the range of 50–1500.”
It should be “The value -1000 represents air, 0 is pure water, and bone (from spongious to compact) typically will be represented in the range of 50–1500.”
Line 876:“Traditionally, CT images have been reconstructed using FBP, but more recently iterative reconstruction methods have been applied also to CT. This allows for reduced image noise and/or a reduction in exposure (mAs), leading to reduced patient doses. ”
The iterative algorithm has been widely used in commercial devices as early as the 2000s. Recently, the next generation of deep learning-based reconstruction algorithms has also been put into use.Nowadays, the FBP algorithm is rarely used.[2].
Line 1782:“Design of a PET facility. ”
Although patients undergoing PET/CT scans generally have a good overall condition, there are occasional situations that require emergency intervention. Therefore, when designing a PET facility, it is important to consider the establishment of an emergency room for critical patients or those who may have an allergic reaction to the iodine contrast medium .
Line 3790:“The wearing of protective aprons is not useful due to the high energy of the
annihilation radiation as they will only reduce the dose by a few percent (Seierstad et al., 2007; Leide-Svegborn, 2010); ”
Neither Seierstad nor Leide-Svegborn's articles mentioned specific data on the protective effect of shielding aprons in positron emission tomography (PET) drugs. Therefore, more literature support, such as He et al.,2017's research[3], should be provided for the conclusion that shielding aprons have no protective effect in PET/CT.
Line 3917:“When a cradle is used to hold the PET syringe injection pig on a flat surface, to allow easier administration of the radiopharmaceutical, the technologists can be further away from the radiation source and reduce exposure of their body and hands.”
In addition to staying away from the radiation source, using injection tables with protective functions is also very helpful in reducing the dose during injections(Fig.1).
Fig.1 A injection tables with protective functions
Line 4872:“Training and education on radiological protection for all staff should be a standard of practice during new staff orientation and induction procedures and as part of the overall education that staff receives as employees during their employment.”
In addition to employed staff, users of PET unit (especially preclinical PET unit) also include non-employees (graduate students, trainees), who may not actually operate the unit, but will come into contact with patients or experimental animals injected with radioactive drugs. This report should address their radiation protection.
Line 5012:“Medical physicist”
Not all institutions have dedicated medical physicists responsible for overseeing the radiation protection programs. This work is generally carried out by nuclear medicine technologists/radiographer. The report should emphasize the importance of medical physicists and recommend that nuclear medicine departments employ dedicated medical physicists.
Line 5041:“Publication 113, defines a Nurse and other health care professionals as a Category 13, 'individuals assisting in diagnostic and interventional x-ray fluoroscopy procedures, radiopharmaceutical administration, or the care of nuclear medicine patients'.”
In radiological protection in PET or PET/CT, nurses are one of the main staff members who come into contact with radiopharmaceuticals, and it is suggested that they be specifically listed.
Additionally, regarding PET/MRI unit, this report only briefly touches on it. However, in practice, due to the complexity of operation (such as the placement of MRI coils, respiratory gating, etc.), nuclear medicine technologists need to spend more time and be in closer proximity to the patients during the operation, making it easier to reach the dose limits. The report should emphasize this point.
Finally, in many countries, doctors and nurses are recognized as distinct professions with relevant certifications. However, nuclear medicine technologists and medical physicists often lack recognition and respect. ICRP should encourage countries and government agencies to recognize the professional of nuclear medicine technologists and medical physicists, so that they are granted the same status as doctors and nurses in the healthcare sector.
References:
[1].Alberts I, Sari H, Mingels C, et al. Long-axial field-of-view PET/CT: perspectives and review of a revolutionary development in nuclear medicine based on clinical experience in over 7000 patients.Cancer Imaging. 2023;23(1):28. Published 2023 Mar 18. doi:10.1186/s40644-023-00540-3
[2].Mileto, A, Guimaraes, LS, McCollough, CH, et al. State of the Art in Abdominal CT: The Limits of Iterative Reconstruction Algorithms. RADIOLOGY. 2019; 293 (3): 491-503. doi: 10.1148/radiol.2019191422
[3].He, X, Zhao, R, Rong, L, et al. Answers to if the Lead Aprons are Really Helpful in Nuclear Medicine from the Perspective of Spectroscopy. RADIAT PROT DOSIM. 2017; 174 (4): 558-564. doi: 10.1093/rpd/ncw255