20N THE JOURNAL OF NUCLEAR MEDICINE Vol. 49 No. 12 December 2008
Molecular Imaging in China:
Looking Back and Forward
Twenty-nine y ago, during my first visit to China as part of a small group sent by the American College of Physicians, I met Xiu Jie Liu, MD, who has been a friend and collaborator over the intervening 3 decades. I took with me on the plane to Beijing a 99Mo/99mTc generator-an act that was relatively easy then but unimaginable today. I had previously sent ahead a ‘‘nuclear stethoscope,''a radioisotope detection system that could measure the left ventricular function of the human heart on a beatby-beat basis after injection of 99mTc-albumin. With this device and the hand-carried genera tor, I carried out the first studies in nuclear cardiology in China at the Beijing Cardiovascular Institute and Fu Wai Hospital, with Dr. Liu assisting (Fig. 1). The nuclear stethoscope was left with Dr.Liu, who subsequently used the device in more than 20 research projects (1-24), including the study of the effect of drugs such as ephedra on left ventricular function.
While in the country in 1979, I gave lectures on advances in nuclear cardiology in several Chinese cities. At that time, all the physician and scientist attendees routinely wore blue Mao suits and caps. Despite their great interest in the topic, even as late as 2005, few centers other than Dr.Liu's had published research papers in the field of nuclear cardiology.
Nuclear medicine began in China in 1956, when the first course on Biomedical Application of Isotopes was held at the Peking Union Medical College. In the mid-1950s, the Chinese Society of Nuclear Medicine was founded, and the first National Radioisotope Training Course was held in 1956 in Xian. A course in clinical nuclear medicine training was held in 1958 in Beijing. The first departments of nuclear medicine were in Beijing, Tianjin, Xian, Shanghai, and Guangzhou. By the end of the decade, these and other courses in clinical nuclear medicine paved the way for the country's first generation of nuclear medicine physicians, and nuclear medicine began to be taught as part of the curriculum in several medical schools. As elsewhere, the first studies focused on the thyroid and included radioimmunoassay analysis. Scanners made in China in the 1950s and 1960s were also used in clinical imaging of the liver, lung, and kidneys. Anger scintillation cameras were produced in China in the 1970s.
Today, 500 hospitals and institutions have nuclear medicine departments or laboratories, most of which are independent (that is, separate) from radiology. These practices include more than 500 g cameras and SPECT scanners, 40 PET instruments, and 54 PET/CT devices. According to a survey by the Chinese Society of Nuclear Medicine, 140,000 bone scans were performed in 2002, accounting for 32% of a ll studies. Heart imaging was carried out in 86,000 patients, accounting for 19% of all nuclear studies, with renal (42,000 cases) and brain (10,500) imaging accounting for 10% and 3%, respectively. More than 10,000 PET/CT studies were performed (3% of total studies), with 85% of these using 18F-FDG for tumor imaging. More than 8 million in vitro nuclear medicine studies were performed.
The radiopharmaceuticals used today in China include: 99mTc-ethylene dicysteine (99mTc-ED) , 99mTc-mercaptoacetyltriglycine, and 99mTc-diethylenetriaminepentaacetic acid
(99mTc-DTPA) for the kidneys; 99mTc-macroaggregated albumin and 99mTc-DTPA for lung imaging; 99mTc, 131I, and 99mTc-sestamibi for thyroid studies; 99mTc-methylene diphosphonate and 99mTc-diethyl iminodiacetic acid for bone studies; 99mTc-sestamibi, 99mTc-tetrofosmin, and 201Tl for myocardial perfusion imaging; and 18F-FDG for myocardial metabolism imaging. 18 F-FDG is also used with
PET/CT for tumor imaging, and 99mTc-sestamibi and 67Ga are used for this purpose with SPECT. Radionuclides used in therapy include 89Sr/90Y, 131I, 32P, and 153Sm-ethylenediaminetetramethylenephosphonate, as well as 99mTc-ethylcysteinate
dimer and 99mTc-hexamethylpropyleneamine oxime in the brain.
Nuclear cardiology in China has grown rapidly in the last few years, with about 200 hospitals carrying out nuclear medicine studies in heart diseases, including myocardial perfusion imaging in the diagnosis and management of coronary artery disease, myocardial metabolism imaging in the assessment of myocardial viability, ventilation/perfusion imaging for assessment of pulmonary embolism, and evaluation of renal function in renovascular hypertension. As in other countries, nuclear cardiology in China is facing challenges from MR and CT imaging and echocardiography. Despite these challenges, the num ber of nuclear studies at Fu Wai Hospital continues to increase (Fig. 2).
Shortly before the opening of the 2008 Olympic Games in Beijing, I had the opportunity to deliver lectures on molecular imaging in 5 Chinese cities. My talks were translated into Chinese by nuclear medicine physicians, who reviewed my PowerPoint slides with me before each talk. Hundreds of young men and women in the audience asked many questions and made comments after the talks. One said that, ‘‘You in the United States have studies approved readily, while it takes a long time to introduce new studies in China.'' I pointed out that we have the same problems in the United States. Dr. Liu said he had never heard so many questions asked after a lecture.
If the advances in nuclear medicine in China are anything like the changes that one can see in communication, transportation, and architecture all over the large cities, China will soon be in the forefront of molecular imaging.