IL74612A - Apparatus for slit radiography - Google Patents

Apparatus for slit radiography

Info

Publication number
IL74612A
IL74612A IL74612A IL7461285A IL74612A IL 74612 A IL74612 A IL 74612A IL 74612 A IL74612 A IL 74612A IL 7461285 A IL7461285 A IL 7461285A IL 74612 A IL74612 A IL 74612A
Authority
IL
Israel
Prior art keywords
slit radiography
radiography
slit
Prior art date
Application number
IL74612A
Other languages
English (en)
Other versions
IL74612A0 (en
Original Assignee
Optische Ind De Oude Delft Nv
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Optische Ind De Oude Delft Nv filed Critical Optische Ind De Oude Delft Nv
Publication of IL74612A0 publication Critical patent/IL74612A0/xx
Publication of IL74612A publication Critical patent/IL74612A/xx

Links

Classifications

    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/02—Devices for diagnosis sequentially in different planes; Stereoscopic radiation diagnosis
    • A61B6/03—Computerised tomographs
    • A61B6/032—Transmission computed tomography [CT]
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/06—Diaphragms
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B6/00—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment
    • A61B6/40—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for generating radiation specially adapted for radiation diagnosis
    • A61B6/4035—Apparatus for radiation diagnosis, e.g. combined with radiation therapy equipment with arrangements for generating radiation specially adapted for radiation diagnosis the source being combined with a filter or grating
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
    • G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
    • G21K1/04—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers
    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
    • G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
    • G21K1/04—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers
    • G21K1/043—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers changing time structure of beams by mechanical means, e.g. choppers, spinning filter wheels
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/26—Measuring, controlling or protecting
    • H05G1/30—Controlling
    • H05G1/36—Temperature of anode; Brightness of image power
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/60—Circuit arrangements for obtaining a series of X-ray photographs or for X-ray cinematography
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05G—X-RAY TECHNIQUE
    • H05G1/00—X-ray apparatus involving X-ray tubes; Circuits therefor
    • H05G1/08—Electrical details
    • H05G1/64—Circuit arrangements for X-ray apparatus incorporating image intensifiers
IL74612A 1984-03-16 1985-03-15 Apparatus for slit radiography IL74612A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL8400845A NL8400845A (nl) 1984-03-16 1984-03-16 Inrichting voor spleetradiografie.

Publications (2)

Publication Number Publication Date
IL74612A0 IL74612A0 (en) 1985-06-30
IL74612A true IL74612A (en) 1989-09-10

Family

ID=19843657

Family Applications (3)

Application Number Title Priority Date Filing Date
IL74613A IL74613A (en) 1984-03-16 1985-03-15 Apparatus for slit radiography
IL74614A IL74614A (en) 1984-03-16 1985-03-15 Apparatus for slit radiography comprising discrete controllable attenuation elements coacting with a slit diaphragm
IL74612A IL74612A (en) 1984-03-16 1985-03-15 Apparatus for slit radiography

Family Applications Before (2)

Application Number Title Priority Date Filing Date
IL74613A IL74613A (en) 1984-03-16 1985-03-15 Apparatus for slit radiography
IL74614A IL74614A (en) 1984-03-16 1985-03-15 Apparatus for slit radiography comprising discrete controllable attenuation elements coacting with a slit diaphragm

Country Status (6)

Country Link
US (3) US4675893A (xx)
EP (3) EP0155065B1 (xx)
JP (3) JPS60253198A (xx)
DE (3) DE3586134T2 (xx)
IL (3) IL74613A (xx)
NL (1) NL8400845A (xx)

Families Citing this family (71)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
NL8303156A (nl) * 1983-09-13 1985-04-01 Optische Ind De Oude Delft Nv Roentgenopnameinrichting met spleetaftasting.
US5164977A (en) * 1983-09-13 1992-11-17 B.V. Optische Industrie, "De Oude Delft" Process and apparatus for effecting slit radiography
NL8401411A (nl) * 1984-05-03 1985-12-02 Optische Ind De Oude Delft Nv Inrichting voor spleetradiografie.
NL8401946A (nl) * 1984-06-19 1986-01-16 Optische Ind De Oude Delft Nv Stelsel voor het detecteren van twee roentgenstralingsenergieen.
DE3500812A1 (de) * 1985-01-11 1986-07-17 Siemens AG, 1000 Berlin und 8000 München Roentgendiagnostikeinrichtung mit halbtransparenter blende
FR2577131A1 (fr) * 1985-02-12 1986-08-14 Thomson Cgr Installation de radiologie a compensation dans un trajet optique de l'image
NL8501795A (nl) 1985-06-21 1987-01-16 Optische Ind De Oude Delft Nv Inrichting en werkwijze voor spleetradiografie met verschillende roentgenstralingsenergieen.
NL8502910A (nl) * 1985-10-24 1987-05-18 Sipko Luu Boersma Roentgen doorlichtings beeldvormer.
US4953189A (en) * 1985-11-14 1990-08-28 Hologic, Inc. X-ray radiography method and system
CA1244971A (en) * 1985-11-14 1988-11-15 Shih-Ping Wang X-ray radiography method and system
US5054048A (en) * 1985-11-14 1991-10-01 Hologic, Inc. X-ray radiography method and system
NL8503151A (nl) * 1985-11-15 1987-06-01 Optische Ind De Oude Delft Nv Piezo-elektrisch verzwakkingstongenstelsel voor een inrichting voor spleetradiografie.
NL8503153A (nl) * 1985-11-15 1987-06-01 Optische Ind De Oude Delft Nv Dosismeter voor ioniserende straling.
NL8503152A (nl) * 1985-11-15 1987-06-01 Optische Ind De Oude Delft Nv Dosismeter voor ioniserende straling.
US4953192A (en) * 1986-04-14 1990-08-28 The University Of Rochester Scanning equalization radiography
US4972458A (en) * 1986-04-14 1990-11-20 The University Of Rochester Scanning equalization radiography
FR2600204A1 (fr) * 1986-06-13 1987-12-18 Thomson Csf Dispositif modulateur de faisceau de rayons x et son utilisation en imagerie medicale pour la realisation de filtres spatiaux
NL8601678A (nl) * 1986-06-26 1988-01-18 Optische Ind De Oude Delft Nv Werkwijze en inrichting voor spleetradiografie.
DE3621868A1 (de) * 1986-06-30 1988-01-14 Siemens Ag Roentgendiagnostikeinrichtung mit einer blende
NL8700781A (nl) * 1987-04-02 1988-11-01 Optische Ind De Oude Delft Nv Werkwijze en inrichting voor contrastharmonisatie van een roentgenbeeld.
NL8701122A (nl) * 1987-05-12 1988-12-01 Optische Ind De Oude Delft Nv Inrichting voor spleetradiografie met beeldharmonisatie.
NL8701820A (nl) * 1987-08-03 1989-03-01 Optische Ind De Oude Delft Nv Inrichting voor spleetradiografie.
NL8702113A (nl) * 1987-09-07 1989-04-03 Optische Ind De Oude Delft Nv Inrichting voor spleetradiografie.
JPS6481193A (en) * 1987-09-22 1989-03-27 Hitachi Ltd Electric bulb type fluorescent lamp
US4872191A (en) * 1987-11-19 1989-10-03 Bio-Imaging Research, Inc. Cam-controlled automatic dynamic focusing for computed tomography
US4845371A (en) * 1988-03-29 1989-07-04 Siemens Medical Laboratories, Inc. Apparatus for generating and transporting a charged particle beam
US4910759A (en) * 1988-05-03 1990-03-20 University Of Delaware Xray lens and collimator
NL8801589A (nl) * 1988-06-22 1990-01-16 Optische Ind De Oude Delft Nv Inrichting voor spleetradiografie voorzien van absorptie-elementen, alsmede werkwijze voor het vervaardigen van absorptie-elementen.
US4947416A (en) * 1988-10-21 1990-08-07 General Electric Company Scanning equalization radiography with stationary equalization detector
JPH02204738A (ja) * 1989-02-02 1990-08-14 Konica Corp Ｘ線ラジオグラフィシステム
NL8902117A (nl) * 1989-08-22 1991-03-18 Optische Ind De Oude Delft Nv Inrichting voor spleetradiografie.
DE3928282A1 (de) * 1989-08-26 1991-02-28 Philips Patentverwaltung Roentgenaufnahmevorrichtung
FR2654917A1 (fr) * 1989-11-24 1991-05-31 Gen Electric Cgr Appareil de radiologie avec filtre d'homogeneisation.
NL9000250A (nl) * 1990-02-01 1991-09-02 Optische Ind De Oude Delft Nv Inrichting voor spleetradiografie.
US5067144A (en) * 1990-05-18 1991-11-19 Hologic, Inc. Equalized radiography using special modulator pins
US5107529A (en) * 1990-10-03 1992-04-21 Thomas Jefferson University Radiographic equalization apparatus and method
JP3188491B2 (ja) * 1990-10-24 2001-07-16 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ Ｘ線記録のダイナミック圧縮方法及びその装置
JPH0657210B2 (ja) * 1991-09-12 1994-08-03 エヌ・ベー・オプテイツシエ・インダストリエ・“デ・オーデ・デルフト” Ｘ線写真装置
DE4228082C1 (en) * 1992-08-24 1993-09-09 Siemens Ag, 80333 Muenchen, De Aperture esp. for X=ray beam - has aperture plate elastically conformable to test object shape
DE4403930A1 (de) * 1994-02-08 1995-08-24 Siemens Ag Röntgenaufnahmevorrichtung
DE4436687C2 (de) * 1994-10-13 1996-12-05 Siemens Ag Röntgenaufnahmevorrichtung
JP2000262515A (ja) * 1999-03-19 2000-09-26 Fuji Photo Film Co Ltd 放射線画像撮影方法及び装置
JP3964271B2 (ja) * 2001-06-22 2007-08-22 株式会社モリタ製作所 医療用走査型デジタルｘ線撮影装置
KR100477930B1 (ko) * 2002-03-29 2005-03-18 김후식 형광증폭상 촬영기
GB0216891D0 (en) * 2002-07-20 2002-08-28 Univ Surrey Radiation collimation
FR2850789B1 (fr) * 2003-01-30 2008-07-11 Ge Med Sys Global Tech Co Llc Tube a rayon x avec filtrage ameliore
US6898269B2 (en) * 2003-02-10 2005-05-24 Ge Medical Systems Global Technology Company, Llc Methods and apparatus for x-ray images
SE527139C2 (sv) * 2003-04-16 2005-12-27 Xcounter Ab Anordning och förfarande för dubbelenergi- och skanningbaserad detektering av joniserade strålning med stackade linjedetektorer och filter
DE10348796B4 (de) * 2003-10-21 2007-09-27 Siemens Ag Vorrichtung zur räumlichen Modulation eines Röntgenstrahlbündels und Röntgenbildsystem
CN1822239B (zh) * 2005-02-17 2010-06-23 Ge医疗系统环球技术有限公司 滤波器和x射线成像设备
US7957507B2 (en) * 2005-02-28 2011-06-07 Cadman Patrick F Method and apparatus for modulating a radiation beam
JP4817859B2 (ja) * 2005-03-04 2011-11-16 株式会社東芝 放射線絞り装置及び当該絞り装置を有する放射線治療装置
US8232535B2 (en) * 2005-05-10 2012-07-31 Tomotherapy Incorporated System and method of treating a patient with radiation therapy
CN101500648B (zh) 2005-07-22 2012-07-04 断层放疗公司 利用剂量体积直方图生成轮廓结构的系统和方法
CA2616292A1 (en) 2005-07-22 2007-02-01 Tomotherapy Incorporated Method and system for evaluating quality assurance criteria in delivery of a treament plan
JP2009507524A (ja) 2005-07-22 2009-02-26 トモセラピー・インコーポレーテッド 変形マップに制約を課す方法およびそれを実装するためのシステム
KR20080039925A (ko) 2005-07-22 2008-05-07 토모테라피 인코포레이티드 생물학적 모델에 기초하여 방사선 요법 치료 계획을적합화시키는 방법 및 시스템
AU2006272730A1 (en) 2005-07-22 2007-02-01 Tomotherapy Incorporated Method of and system for predicting dose delivery
US7639854B2 (en) 2005-07-22 2009-12-29 Tomotherapy Incorporated Method and system for processing data relating to a radiation therapy treatment plan
EP1907981A4 (en) 2005-07-22 2009-10-21 Tomotherapy Inc METHOD AND SYSTEM FOR DOSE EVALUATION ADMINISTERED
ATE507879T1 (de) 2005-07-22 2011-05-15 Tomotherapy Inc System zur verabreichung einer strahlentherapie auf ein sich bewegendes zielgebiet
JP2009502253A (ja) 2005-07-22 2009-01-29 トモセラピー・インコーポレーテッド 関心の移動領域に対して放射線療法を施すシステムおよび方法
JP2009502251A (ja) 2005-07-22 2009-01-29 トモセラピー・インコーポレーテッド 放射線治療システムによって送達された線量を評価するシステム及び方法
US8442287B2 (en) * 2005-07-22 2013-05-14 Tomotherapy Incorporated Method and system for evaluating quality assurance criteria in delivery of a treatment plan
KR20080044250A (ko) 2005-07-23 2008-05-20 토모테라피 인코포레이티드 갠트리 및 진료대의 조합된 움직임을 이용하는 방사선치료의 영상화 및 시행
US20090041200A1 (en) * 2005-07-23 2009-02-12 Tomotherapy Incorporated Radiation therapy imaging and delivery utilizing coordinated motion of jaws, gantry, and couch
US20080043910A1 (en) * 2006-08-15 2008-02-21 Tomotherapy Incorporated Method and apparatus for stabilizing an energy source in a radiation delivery device
CN107469240B (zh) 2013-02-26 2020-04-21 安科锐公司 多叶准直器和用于准直治疗放射束的系统
DE102016204870B4 (de) 2016-03-23 2023-11-23 Siemens Healthcare Gmbh Blendenvorrichtung zur Kollimation eines Röntgenstrahlenbündels einer Röntgeneinrichtung
CN107490805A (zh) * 2017-09-19 2017-12-19 北京君和信达科技有限公司 辐射装置及辐射检查系统
CN107479102A (zh) * 2017-09-19 2017-12-15 北京君和信达科技有限公司 辐射检查系统及方法

Family Cites Families (35)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1164987A (en) * 1914-02-03 1915-12-21 Siemens Ag Method of and apparatus for projecting röntgen images.
US2996267A (en) * 1954-12-06 1961-08-15 James R Warren Vibration damping mechanism
US2943205A (en) * 1957-10-31 1960-06-28 Rca Corp Radiant energy control apparatus
US3101407A (en) * 1959-04-09 1963-08-20 Jr John Daniel Shipman Fluoroscope system utilizing an image storage tube
US3275831A (en) * 1963-05-16 1966-09-27 Industrial Nucleonics Corp Radiation beam shutter collimator
US3402292A (en) * 1963-06-07 1968-09-17 Baecklund Johannes Apparatus for x-ray analysis of a material having a specific filter in the primary x-ray beam path
US3346737A (en) * 1964-09-22 1967-10-10 Applied Res Lab Inc Hydraulically controllable spectroscopic slit apparatus for making precision adjustments of the slit width
US3806062A (en) * 1970-04-29 1974-04-23 Hughes Aircraft Co Passive eddy current nutation damper
US3660664A (en) * 1970-05-11 1972-05-02 Robert P Pasmeg Wedge for varying cross-sectional intensity of beam of penetrating radiation
SE347859B (xx) * 1970-11-30 1972-08-14 Medinova Ab
US3912936A (en) * 1972-09-15 1975-10-14 Machlett Lab Inc X-ray image intensifier system
GB1475492A (en) * 1973-06-01 1977-06-01 Emi Ltd Apparatus for examining objects by means of penetrating radiation
US3868082A (en) * 1973-07-16 1975-02-25 Lkb Produkter Ab Device in a microtome for damping of vibrations
DE2351473A1 (de) * 1973-10-13 1975-04-17 Philips Patentverwaltung Anordnung zur belichtungssteuerung fuer ein roentgenuntersuchungsgeraet
US4018716A (en) * 1975-06-16 1977-04-19 The Machlett Laboratories, Incorporated Radiographic system
JPS5738855Y2 (xx) * 1975-12-10 1982-08-26
US4071771A (en) * 1976-06-28 1978-01-31 Ohio-Nuclear, Inc. Shutters for X-ray scanners
US4200799A (en) * 1976-07-15 1980-04-29 Tokyo Shibaura Electric Co., Ltd. Tomographing device
DE2633059C3 (de) * 1976-07-22 1979-10-18 Siemens Ag, 1000 Berlin Und 8000 Muenchen Röntgen-Primärstrahlenblende
US4132895A (en) * 1976-08-28 1979-01-02 Emi Limited Radiography
US4099063A (en) * 1976-11-10 1978-07-04 General Electric Company X-ray field defining masks for a spot film device
JPS5368994A (en) * 1976-12-02 1978-06-19 Toshiba Corp X-ray apparatus
US4086494A (en) * 1976-12-17 1978-04-25 Malak Stephen P Radiation collimator for use with high energy radiation beams
JPS53110495A (en) * 1977-03-09 1978-09-27 Toshiba Corp Radiation tomograph ic device
JPS53114380A (en) * 1977-03-16 1978-10-05 Toshiba Corp Tomographic pickup unit by radiation
DE2814242C3 (de) * 1978-04-03 1981-07-09 Siemens AG, 1000 Berlin und 8000 München Schichtgerät zur Herstellung von Transversalschichtbildern
JPS6239548Y2 (xx) * 1978-08-08 1987-10-08
JPS5540531A (en) * 1978-09-14 1980-03-22 Tokyo Shibaura Electric Co Wedge filter of computerrtomography device
JPS5686797U (xx) * 1979-12-10 1981-07-11
US4426721A (en) * 1980-10-07 1984-01-17 Diagnostic Information, Inc. X-ray intensifier detector system for x-ray electronic radiography
US4547893A (en) * 1981-06-12 1985-10-15 Analogic Corporation Continuous wave fan beam tomography system having a best-estimating filter
DE3138939A1 (de) * 1981-09-30 1983-04-14 Siemens AG, 1000 Berlin und 8000 München Roentgenuntersuchungsgeraet
DE3141987A1 (de) * 1981-10-22 1983-05-05 Siemens AG, 1000 Berlin und 8000 München Roentgendiagnostikeinrichtung
US4404591A (en) * 1982-01-04 1983-09-13 North American Philips Corporation Slit radiography
SU1052756A1 (ru) * 1982-07-07 1983-11-07 Предприятие П/Я Г-4461 Гаситель механических колебаний

Also Published As

Publication number Publication date
US4984258A (en) 1991-01-08
JPH0415692B2 (xx) 1992-03-18
EP0155064B1 (en) 1992-04-29
JPS60253198A (ja) 1985-12-13
EP0155064A2 (en) 1985-09-18
IL74613A0 (en) 1985-06-30
JPS60253200A (ja) 1985-12-13
NL8400845A (nl) 1985-10-16
EP0155065A2 (en) 1985-09-18
DE3586134T2 (de) 1992-12-03
DE3563280D1 (en) 1988-07-14
JPH0415693B2 (xx) 1992-03-18
EP0158382B1 (en) 1988-06-08
IL74614A0 (en) 1985-06-30
EP0155065B1 (en) 1992-06-03
IL74613A (en) 1990-03-19
EP0155065A3 (en) 1989-03-22
JPS60253199A (ja) 1985-12-13
IL74614A (en) 1991-06-30
EP0158382A1 (en) 1985-10-16
IL74612A0 (en) 1985-06-30
DE3586134D1 (de) 1992-07-09
US4675893A (en) 1987-06-23
US4715056A (en) 1987-12-22
DE3585925D1 (de) 1992-06-04
EP0155064A3 (en) 1989-03-22
JPH0415691B2 (xx) 1992-03-18

Similar Documents

Publication Publication Date Title
DE3563280D1 (en) An apparatus for slit radiography
GB2155648B (en) An exposure apparatus
EP0153786A3 (en) X-ray apparatus
DE3561038D1 (en) Apparatus for slit radiography
GB2155201B (en) An x-ray exposure apparatus
DE3265470D1 (en) Improved slit radiography
EP0178660A3 (en) X-ray exposure apparatus
GB8501151D0 (en) Radiological apparatus
DE3664243D1 (en) Apparatus for slit radiography
GB8531604D0 (en) Ct apparatus
GB2157930B (en) Radiography apparatus
GB8503115D0 (en) Apparatus for exposure
DE3573479D1 (en) Radiographic apparatus
IL87603A0 (en) Equipment for slit radiography
EP0306081A3 (en) Apparatus for slit radiography
EP0136732A3 (en) X-ray apparatus
DE3573064D1 (en) Tomographic apparatus
GB2154449B (en) Apparatus for central electroanalgesia
GB8329240D0 (en) X-ray apparatus
GB8404085D0 (en) X-ray apparatus
GB8333435D0 (en) Radiographic apparatus
EP0161093A3 (en) Radiographic apparatus
GB8405550D0 (en) Detector apparatus
IL87253A (en) Device for slit radiography
DE3565608D1 (en) Radiographic apparatus

Legal Events

Date Code Title Description
KB Patent renewed
RH1 Patent not in force