Cyclotron Downtime Reduction

Cyclotron Downtime Reduction

Sritrang Panpitpat, Thanita Saonum, Ananya Ruangma*

Oncology Imaging and Nuclear Medicine unit, Wattanosoth Hospital,

Bangkok Hospital Medical Center, Bangkok, 10310

E-mail: *

ABSTRACT

Cyclotron is one of the crucial equipment to produce F-18 FDG or F-18 fluorodeoxyglucose, the most commonly used in medical imaging modality Positron Emission Tomography (PET). Bangkok Hospital Medical Center bought a TR-19 PET cyclotron and had it installed in Wattanosoth Hospital, the cancer center, in April 2005. The production of FDG started in October 2005. During the first year of production, there were 66 times of production problems related to cyclotron. Thirty-five of the problems were detected before production and were solved in-time. Nineteen of them resulted in late production which caused the patients to wait for a long time. Twelve of them resulted in fail production which caused us to cancel the patients. To make a better service for patients, our production unit realized that it is necessary to find solutions to minimize the downtime of cyclotron and minimize the failure of FDG production. After analyzing the problems, we could categorize the problems into three groups (59% from environment of the cyclotron site, 30% from equipment problems, and 11% from human errors). The twelve fail productions caused by facility’s environment 6 times and the equipment itself 6 times. We set a regular meeting with engineering service department to find the solution for those problems. The problems related to equipment were solved by improvement of maintenance services. The human errors were eliminated by a check-list sheet. This check-list sheet is very helpful. It is not only used for cyclotron operating process but also it is for monitoring important parameter. The downtime of cyclotron was reduced significantly from 14% in 2006 to 3% in 2007.

Keywords: Cyclotron, downtime, radiopharmaceutical production

INTRODUCTION

Wattanosoth Hospital is Thailand’s first private hospital devoted entirely to the diagnosis and treatment of cancer. We are committed to provide cancer patients with the most effective range of traditional and innovative cancer treatment available. Early detection of cancer is critical to the success of treatment. For this reason, Thailand’s first PET/CT scanner and cyclotron were installed and used as a cancer diagnostic technology at Wattanosoth.

A cyclotron is a particle accelerator that can produce short-lived PET radioisotopes for medical and research uses. Wattanosoth

hospital installed a cyclotron (TR-19 PET) in May 2005 and started the production of PET radiopharmaceutical in November 2005. The TR-19 PET cyclotron at Wattanosoth Hospital was shown in Figure 1. Fluorine-18 (F-18) was the first radioisotope made from the cyclotron to produce F-18 fluorodeoxyglucose (FDG).

Since it was the first cyclotron installed in Thailand and it was complicate equipment, there was no cyclotron specialist who would be

able to take care of the system. The cyclotron distributor proposed itself to provide service maintenance for the cyclotron and to produce the PET radiopharmaceutical. Therefore, the hospital decided to outsource the distributor for maintenance and production of PET radiopharmaceutical. After about six months, the hospital evaluated the performance of the distributor for the maintenance and the production of PET radiopharmaceutical. The distributor could not perform the service to meet the requirement of the hospital, especially the maintenance. The cyclotron’s downtime was very high due to inadequate preventive maintenance. It affected the quality of care of the hospital. The patients had to delay the treatment plan since they had to wait for diagnosis result from PET/CT. It also affected the image of the hospital. Therefore, the hospital decided to terminate the outsourcing and start to do maintenance and produce radiopharmaceutical by hospital staff.

Figure 1: TR-19 PET Cyclotron at Wattanosoth Hospital

After reviewing the data, the hospital found that since operation of cyclotron and production of radiopharmaceutical from November

2005 to December 2006, there were 13 incidences on production of F-18 that caused cancellation of PET examination. The downtime was about 59 days. There were 19 incidences that cause the delay of F-18 production and there were 35 incidences of F-18 production problems which were solved in time. The causes of these problems could be categorized into three major groups. About 30% of the problems were due to the equipment itself which might be the defect of the cyclotron, untrained engineer from the distributor, and inadequate preventive maintenance. The facility’s environment also affected the equipment. It caused about 59% of the problems. The twelve fail productions caused by facility’s environment 6 times and the equipment itself 6 times. Examples of facility’s environment problem are water temperature problem, uncontrollable temperature and humidity in the cyclotron vault due to the inapt air conditioner system and water leakage problem. The facility’s environment problems also include unstable electricity. There were incidences of electrical surge during production causing delay F-18 and radiopharmaceutical production. The last causes of problem (about 12%) were due to human error. The cyclotron operators did not check whether the cyclotron system was ready for operation and did not follow standard operating procedure, etc. All of the problems mentioned above were shown in the Figure 2.

Figure 2: Summary of the analysis of the cause of production problems.

From the data, we analyzed the root causes and tried to solve each problem. Therefore, it leaded to “Cyclotron downtime reduction”

project. The objective of the project was to minimize the causes that resulted in F-18 production problems, either delay of F-18 production or no production at all from 2 major causes: the facility’s environment and human errors. The problems were solved by setting up a monitoring and alarm system for condition of the vault (temperature and humidity). If either temperature or humidity was out of the limit, it could be corrected in time. A check list to check critical values and critical condition of the system was also create to assist the cyclotron operators to make sure of the readiness of the system before operation.

MAIN SUBJECT MATTER

The process of radiopharmaceutical production includes 3 parts. All of 3 parts are performed at the same time. The first part is production of F-18 with Cyclotron. A cyclotron operator will check over all parameter and condition of the system. She will calculate the amount of F-18 needed for the production of the day. Then she will warm up the system and bombard the O-18 water target with proton beam to get F-18. All of the above process normally takes about 1:30 hours. The second part involves the FDG synthesis. A chemist will start preparation for FDG synthesis at the same time as the cyclotron operator start her work. The chemist will check overall condition of the automated synthesis module, clean the system and prepare reagents, columns and all necessary equipment for FDG production. Finally, she will test the system before starting synthesis of FDG. The process for preparation of FDG production takes about 1:30 hours (same as the F-18 production from Cyclotron). While the cyclotron finishes producing F-18, the automated FDG production module will be ready to start. The cyclotron operator will send the F-18 to the hot cell and the chemist will start the FDG synthesis. To transfer F-18 to hot cell and to synthesis FDG normally take about 1 hour to 1:30 hours. Finally, the last process for radiopharmaceutical production is to do quality control of the product. While the other 2 part of production (F-18 production and preparation of synthesis) are working, quality control personnel will start and check all equipment for quality control and prepare all necessary apparatus. After she gets a sample of FDG from the chemist, she will do all of the test according to the standard to make sure that the product is qualify for patient injection. The process to do the test will take about 30 minutes after FDG synthesis finished. After that, the FDG is ready to be used for each patient. The overall process from the start of production of F-18 to finish product and ready to be use for patient takes about 3:30 hours. Figure 3 shows the schematic for the timeline for each process. If there are any problems in each process, the overall production of FDG will be delayed and resulted in delay of patients care process. In case of severe problems that can not be resolved in time, the PET examination of that day may have to be canceled.

Figure 3: showing the schematic of timeline for the process of FDG production.

In this project of cyclotron downtime reduction is focused only on the problem of F-18 production (the first part), since it caused the

most of incidences.

As mentioned in the introduction, the causes of the problem on F-18 production with cyclotron can be categorized into 3 groups. The

first group of the problems related to facility’s environment which did not meet site requirement and uncontrollable temperature and humidity in cyclotron vault. The second group of problems was due to lacking of preventive maintenance of the cyclotron system from the outsource company and untrained service engineer. The third group of problems was due to human error such as the cyclotron operator did not follow the correct procedure and did not thoroughly check all the critical values and condition of the system before operating the cyclotron.

Data Analysis for the Facility’s Environment Problems

To minimize the cyclotron’s downtime, the first group of problems need to be correct is facility’s environment problems because there were a lot of incidences due to these problems. We also correct human errors problems because it can be solved immediately. We did root caused analysis and brain stormed to solve the problem.

The problems due to facility’s environment were analyzed and summarized the root caused as follow:

The water leakage from the ceiling of the cyclotron vault. Occasionally, there was a small amount of water leaking from the ceiling of the cyclotron vault as shown in Figure 4. It caused high humidity in the cyclotron vault and it was very difficult to control the humidity.

Figure 4: water leakage from t he ceiling of the cyclotron vault.

The problem due to chilled water. The temperatures of the chilled water were fluctuated. It could not be controlled to be in the decided range. Some time the water temperature did not meet the operation requirement of cyclotron. The General Support Department of the hospital did not have a standard operating procedure when the cyclotron operator notified the engineer for the problem. Therefore, it delayed the F-18 production process.
The problem related to electrical surge. There were some incidences of electrical surge which affect and damage the cyclotron system. It also caused some of the part of cyclotron stop working. If it happened at night while nobody monitor the system, the cyclotron operator had to solve the problems in the morning before starting operation and would have to delay to F-18 production. Moreover, the electrical surge and the harmonic in electricity from each instrument also disturbed other medical instrument in the surrounding area.
The problem about uncontrollable humidity that affected electronic system of the cyclotron. Figure 5 shows condensation of water on Ion Source and Injection System (ISIS) when the humidity of the cyclotron vault is high. Since ISIS has chilled water, when the humidity is high, the temperature different between the chilled water and the cyclotron vault easily causes water condensation around ISIS.

Figure 5: High humidity causes water condensation on ISIS.

The problem about uncontrollable temperature in cyclotron vault and electronic area. When the room temperature was much higher than the temperature of chilled water, there was condensation of pipe of chilled water. It caused high humidity. And if the condensation occurred near the high voltage area, it can caused electric short circuit and it can damage some equipment.

Summary of the facility’s environment problems which caused about 59% of incidences in F-18 production was shown in the

diagram on Figure 6.

Figure 6: summary of the facility’s environment problems.

Correction Methods

To correct the problems related to facility’s environment, it needed cooperation from many involved departments such as the General Support Department which is an outsource company of the hospital, the building designer and the system designer, and the Medical Technology Department who had a role to control the standard of medical equipment in the hospital, etc. Therefore, to solve these problems, a regular meeting of all involved parties to brain storm was necessary. The hospital director helped to arrange the meeting and cooperation from all parties. The process of solving the facility’s environment (Plan-Do-Check-Act) is shown in Figure 7.

Figure 7:Process of solving facility’s environment problems.

The summaries from meetings are as follow:

Solving water leakage from the cyclotron vault shielding:

The building and system designers and the civil engineers who monitored the construction of the building had analyzed the problems and presumed that the problems might due to the construction system/method, the designed location of the facility, and the high level of underground water level. Cyclotron had to locate on basement floor of the hospital and it was a big machine. In order to install the cyclotron on the basement, the designer had design to leave some area of the ceiling of the cyclotron vault open and close the ceiling after installation. Therefore, there was a small joint on the ceiling after closing. There was also a space about one meter between the ceiling and the ground floor. Moreover, there were restrooms on the ground floor above the cyclotron vault. When there were incidences of water leakage from a water pipeline, the space between the ceiling and the ground floor act as a water container. And, the water will drip from the ceiling of the cyclotron vault as shown in Figure 8.

Figure 8: water leakage from ceiling of cyclotron vault.

Solving chilled water problem:

From the meeting, the General Support department would assign a staff to monitor chilled water. And the General Support department will have a standard operating procedure when there are any problems with chilled water. The cyclotron engineer will also monitor chilled water temperature before operation. And, if the chilled water temperature is out of range, she will notify the General Support department.

Solving electrical system:

Even though the cyclotron system used a UPS, there were some parts that were not connected to the UPS. Therefore, when there was out of electric, that part of the system would not work. Engineers from the General Support department had investigated all the electrical line of the cyclotron system and moved all the electrical line to use electric from a UPS. The problems about short circuit that affect the cyclotron and many other medical equipments in the surrounding area were solved by using separate UPS for each individual equipment and ensured that each equipment use the right size of UPS.

Solving humidity problem:

There were many sources of humidity problem. For example, the air conditioner system was not able to control the high humidity in the cyclotron vault in Thailand. The cyclotron vault was not air tight. There are some small areas that air can flow in and out of the vault. The vault was underground and very humid. There was a de-ionized water container which was not adequately seal.

For this humidity problem, there are two time-frame for correction plan. The short-term correction method for humidity problem was to install three dehumidifiers and install monitoring and alarm system. The long-term correction action was to install new air conditioner system and renovate the cyclotron vault. Since the long-term correction plan needs to use a high amount of money, it will be implemented in the next budgeting year.

Solving temperature problem:

The temperature in the cyclotron was occasionally out of range. The air conditioning system was off when there was out of electric or electrical surge. When the air conditioning system stopped working, an engineer from the General Support department could not go inside the cyclotron vault to fix the problem because it was the restricted area. The correction action was to install an auto start system to the air conditioning system. Therefore, the air conditioning system will automatically start after it was off. Furthermore, a monitoring and alarm system was installed to monitor the temperature in the vault.

Data Analysis for Human Error Problems

After root caused analysis of human error problems, we found that there were many causes. First, the cyclotron system was a complicated system. There are many part of the system to make the cyclotron to operate properly. Before operating the cyclotron, the cyclotron operator needs to check the system thoroughly to ensure that the system is ready. If there is any point that she overlook, it may affect the production. Furthermore, operating a cyclotron is complicate and needs skilled operator. In addition, the production starts very early in the morning. She might be sleepy if she did not get enough sleep.

Normally, there is a skillful cyclotron engineer. On her day off, another trained cyclotron operator will operate the cyclotron. If she