The lith Symflosium on Accelerator Science and Technology, Harima Science Garden City, 1997.

Present Status of NmS - HIMACEiichi TAKADA, Satoru YAMADA, Masami TORIKOSHI, Katsuto TASHIRO, Tomohiro TAKAYASU,Mitsuru SUDA, Yukio SATO, Shinji SATO, Koji NODA, Masayuki MURAMATSU, Takeshi MURAKAMI,Masayuki KUMADA, Shigeru KOUDA, Atsushi KITAGAWA, Mitsutaka KANAZAWA, Toshihiro HONMA,Kazuhiro UEDA*, Hideo TSUBUKU*, Tomohito TOGASHI*, Yoshinobu SANO*, Katsumi OKUMURA*,Hirotsugu OGAWA*, Susumu NAMAI*, Chihiro KOBAYASHI*, Yukio ISHIKAWA*, Toshitaka FUKUSHIMA*,
and Takashi AOKI*
4-9-1, Anagawa, Inage-ku, Chiba 263, JAPAN
National Institute of Radiological Sciences
Konakadai, Inage-ku, Chiba 263, JAPAN
2-13-1,
Corporation
Engineering*Accelerator

Abstract
NIRS-HIMAC has been used for clinical trial ofcancer particle therapy since it was commissioned 3 years
More than 300 patients were treated andago.
preliminary evaluation is good enough to extend moretreatment in advanced phase. Beam was also providedfor physics and biology experiments from He to Ar.
Recent developments include RFKO extraction
system for gating beam with patient's breathing,preparation of secondary beam lines for positron emittersuch as nc, modification oflinac system for Time Sharing
Acceleration, and installation of 18 GHz ECR for
providing heavier ion such as Fe.
1. Introduction

In the last symposium of the series (Symp. Ace. Sci.
& Tech. in October 95), we reported the HIMAC
commissioning and initial results of therapeutic irradiationof carbon ion for cancer treatment, which was carried outfor about 50 patients at the time. [1] Since then, we haveadvanced the ion-therapy programme both in quality andquantity. The number of patients who were treated atHIMAC now totals more than 300. Table I shows thebreakdown of tumor targets (patients) that were irradiatedat HIMAC. It is readily seen that both number ofpatients and tumor site are increasing. Since medicalresult (of tumor control) needs to follow the cases at leastin 5 years range, present evaluation is preliminary.
Nevertheless, 1)Damage to normal tissue and skin is
usually minimal except for intestine with prostatetreatment. 2)Local control of tumor depends on site, but
as for Head & Neck cases, in more than 90 % of tumors
responded to irradiation and reduced its volume to lessthan half in 18 months period. For more clinical details,
see Ref.[2].
We report here progress in the last two years, which
would characterizes HIMAC as an excellent medicalaccelerator.
2. Machine Operation

Presently, HIMAC provides beams for treatments
and experiments for 39 weeks per year, from Monday
evening to Saturday (or Sunday morning once a month).
It amounts to about 2200 hours operation in case of lower
ring and its following courses from April to August 2(including the first week of operation, 18 weeks). Of
2200 hours, more than 580 hours were allocated toclinical use. Physics experiments usage are nearly 700
hours. The rest was shared by beam tuning and waiting
for user. Daily operation of HIMAC is carried out byoperators from AEC, a company contracted for operation,maintenance, and relevant support of HIMAC with more
Clinical treatment practice has
than 30 operators.
extended to use beam of different energy, and daily
operation now includes energy change and reconfirmation
process of the beam. Details of the operations aredescribed in another contribution to this symposium. (3]3. Recent Developments
3.1 Respiration-Gated Beam Control
A motion of body by breathing, or respiration,
causes unwanted change in position (and in shape) of theSince the motion deteriorates thetarget volume.
localization of beam, we had developed a system of beam
control and irradiation to avoid superfluous dose tonormal organ. [4] The system was installed to HIMAC
in March '96, and began operation in June '96, including
a beam deceleration operation in the ring for nonextracted beam.[5] Since then most of lung and livercancer treatments, which amounts to more than 50
patients, have been carried out using the system. In
actual operation, efforts are paid to elongate flat top
period to the maximum possible duration, and in somecases, more than 90 % of spill was used for a treatment
due to the improvement.
3.2 Construction ofSecondary Beam Course
The verification of the distribution of beam within
the target volume is one. of the key issue to establish
advanced method of particle therapy. So far, the rangecalculation was limited by several factors. A beam of ·positron emitter nucleus can be used as a verification tool-347-

The 11th Symposium on Accelerator Science and Technology, Harima Science Garden City, 1997of the range with PET or positron camera technique.
Fundamental physics research will also be an importantarea of the secondary beam facility. We began toconstruct a secondary beam course that should be used for
diagnostic and clinical purpose with 11 C beam in mind.[6]Preliminary tuning for upstream section has been underway since April '97, and the tuning system is performing
well.[7]operation of irradiation port and/or energy switching fortreatment is an important element of medical accelerator
development. Automatic tuning procedure has been
proposed and tested for daily operation.[16] Further
analysis and improvement for quicker beam delivering isunder way. It was also tried successfully to deliver joined
beams from both rings for apparent duty of about 80 %.

3. 3 Studies on Synchrotron Beam
Synchrotron studies to understand beam condition
better have been performed. Tune shift at the injection
was measured and the space charge effect was found toplay non-negligible role.[8] The COD measurement andcorrection was also investigated for horizontal direction
and it was confirmed that correction scheme works fme toreduce the COD from about 10 mm (max.) to about 2
mm.[9] Further, study was done on effect of digitizing
step size on acceleration efficiency in RF system thatutilizes Direct Digital Synthesizer, and HIMAC's 0.2
Gauss step clock is estimated adequate in terms ofacceleration efficiency.[lO] Both of the ordinary andRFKO slow extraction were investigated for improvementon spill structure, emittance, and efficiency.[ll]3. 7 Investigations ofrelevant technology
The Power supply technology for synchrotron
accelerator is another focus of activity. Reducing ripple
components in power supply has been pursued and results
are reported elsewhere.[l7] In connection with thiseffort, measurement of ripple at the magnets are tried withnovel scheme.[l8] Eddy current effect in solid magnet
has been studied for phenomena of minutes to hours timescale.[l9]A beam spill ripple monitor has been developed toreplace the present scintillation monitor. [20] Control
system development has been carried out in order torealize spill control in feed forward scheme.[21] NewVME board was designed and is being tested for fastermulti-pattern synchrotron operation than now. [22]Safety control system[23] has been reinforced to stabilize
its operation in peak-demand.

3.4 Ion Sources
Improvement and development works on ion
sources were actively pursued. New 18 GHz ECR
source was installed and has been tested for Fe and otherheavier ions.[l2] Study on compact ion source has been
carried out to fmd suitable design of simple ion source for
medical application.[l3] In working sources ofECR andPIG, efforts for higher output and stability beam wereextended. Also seeked was for variety of beam species,e.g., 13 C beam, Hz+ molecular ion from CH4 operated
ECR, and copious beam of C+z from PIG source.
3.5 Time Sharing Acceleration
In order to exploit the two rings and the experimentbeam courses as well as treatment, Scheme foraccelerating beams of different Q/A in linacs have beendeveloped [14] and necessary hardware modification has
been completed except for transport into the synchrotron.
This feature will enable to accelerate, e.g., C for upperring , Ar for lower ring, and He for 6 MeV/u experimentcourse. In this scheme, beam monitoring must be nondestructive when tuning one beam while the others areused. Development to meet this need of non-destructive
monitor has been done and is reported in the presentsymposium.[l5]3.6 Improvements in High Energy Beam Transport
Lessening the manual adjustment work in routine

3.8 Overview ofdevelopment in irradiation system
Several works are reported to advance precisionand power of patient irradiation system in the last
symposium. 3D irradiation system has been tested andcorresponding treatment planning software is now underdevelopment.
For more efficient use of the beam,
dynamic wobbling scheme has been prepared andexperimented.
In the area of dosimetry, efforts toaccurate measurement of dose distribution in individual
patient fteld, have been made especially in transverse
directions. It is also planned to compare chamber andother measuring device output with each other world-wide.
In doing this, we are going to provide proton beam fromHz+ acceleration at synchrotron. Measurement of beam
fragmentation and refmement of dose calculation to takethe fragmentation into account is under way. Also therespiration gate system is to be sophisticated in order totreat the gate signal discriminator level more
systematically. A comprehensive simulation system is
now under design for extensive use of existing treatment
room and for development of precise patient positioning
system and advanced treatment planning.

4. Future Extension
Electron cooling device is to be installed in asynchrotron ring. This addition will enable emittance-348-

The 11th Symposium on Accelerator Science and Technology, Harima Science Garden City, 1997

reduction of injected beam and thus lead not only toincrease the intensity of accelerated/extracted beam, butalso to shorten the pulse length to fit fast handling of thebeam. It will also improve control of beam in size andstability for more precise irradiation and measurement.
A new activity is being organized for a hospital based
synchrotron light source. [24] In this line, R&D work
has started for a 7 T superconducting wiggler magnet.
Acknowledgment
The authors are grateful to AEC members who
worked together in HIMAC accelerator facility. Theirgratitude also goes to Dr. K. Kawachi, Dr. T. Kanai, andcolleagues of Accelerator Physics and Engineering.
Division. They appreciate continuous encouragement byDr. Y. Hirao.
References[1] S. Yamada et al., in Proc. 1Oth SAST (JAERI-Conf.
95-021), pp.5-7. S. Yamada, Proc. PAC95, p.9.
[2] H. Tsujii et al., Proc. Denton Conf. '96 (AIP-CP392),
p.l269. K. Morita et al., Proc. EPAC96, p.237.
[3] Y. Sano et al., "Progress in HIMAC AcceleratorOperation", in these proceedings.
[4] K. Noda et al., Proc. lOth SAST, p.439.
K. Noda et al., Nucl. Instr. & Meth. A374(1996)269.
K. Noda et al., Proc. EPAC96, p.2656.
[5] M. Kanazawa et al., ibid., p.2653.
[6] S. Kouda et al., "New Secondary Beam Course for
Medical Use in HIMAC", Proc. PAC97.
[7] M. Suda et al., "Secondary-Beam Tuning System atHIMAC", in these proceedings.
[8] K. Noda et al., "Measurements on Injection Property
in HIMAC Synchrotron", Proc PAC97.

[9] M. Kanazawa et al., Proc. EPAC96, p.1710.
[lO]M. Kanazawaet al., "Beam test of the acceleration
system with the DDS in HIMAC Synchrotron", Proc.
PAC97.
[ll]K. Noda et al., Proc. 16th RCNP Int. Symp. (Osaka,March '97), to be published.
[12]M. Yamamoto et al., "Study of the Extraction Configuration ofNIRS-HEC Ion Source", in theseproceedings. T. Okada et al., Proc. BEAMS1996(Tokyo), P.135. (text in Japanese)[13]M. Muramatsu et al., Proc. 21st LINAC Meeting,
1996, p.337. (text in Japanese)[14]T. Fujimoto et al., "Time-Sharing-Acceleration inthe HIMAC Injector", in these proceedings.
[15]T. Katoh et al., "Non-Destructive Velocity Monitor
for the HIMAC injector", in these proceedings.
[16]M. Torikoshi et al., Proc. EPAC96, p.2462[17] M. Kumada; Proc. 16th RCNP Int. Symp. (Osaka,March '97), to be published. M. Kumada et al.,Proc. EPAC96, p.2352, p.2355, p.2358.
M. Kumada and K. Sato, Proc. 2nd Symp. Power
Supply Tech. for Ace., 1996, p.8. (in Japanese)[18]T. Aoki et al., in these proceedings.
[19]M. Kumada et al., "Eddy current effect of very longtime constant of Block Magnets", Proc. PAC97.
[20]S. Sato et al., "Beam Ripple Monitor with secondaryelectron", in these proceedings.
[21]N. Araki et al., Proc. BEAMS1995(Tokyo), p.123.
(text in Japanese)[22]E. Takada et al., in Proc. ICALEPCS95(Chicago).
[23]T. Kohno et al., Proc. BEAMS1995(Tokyo), p.ll9.
"Safety Management System for HIMAC" (text inJapanese)[24]M. Torikoshi et al., "A Plan of Synchrotron Light
Source for Medical Application at NIRS", Proc.
PAC97.

. countmg. ). M arch97 and on prerllDJllary
N urnber of tumors treated at HIMAC (b ased on·the press re ease mSemester
3152647Total'94.6-8 10-95.2 95.4-8 9-96.2 96.4-8 9-97.2 97.4-8 94.6-97.8 Protocol#
Site
Head& Neck
53861120
558 93 0 114,9 504,960 112
Brain
644
19428 9302
Lung
6741216449 9303
Liver
5768733 9401,9603
Prostate
8102
7532 9402
Uterine Cervix
36310279403
5Bone & Soft27615 9501
Esophagus
156 9502/3
Miscellaneous
8710161556 9404
Total
34718823449304
71
Number of patient ts 2~3less than total number of tumor.
Table I-349-