A cancer patient lies in the radiation therapy room at the National Oncology Centre in Sanaa, Yemen, August 8, 2018. REUTERS/Khaled Abdullah SEARCH "YEMEN CANCER" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES. 

A cyclotrone is pictured inside a radiation bunker at the headquarters of Belgian group IBA, which makes proton therapy machines for the treatment of cancer, in Louvain-la-Neuve, Belgium, July 22, 2016. Picture taken July 22, 2016. REUTERS/Francois Lenoir

A worker inspects a cyclotrone inside a radiation bunker at the headquarters of Belgian group IBA, which makes proton therapy machines for the treatment of cancer, in Louvain-la-Neuve, Belgium, July 22, 2016. Picture taken July 22, 2016. REUTERS/Francois Lenoir

A worker inspects a cyclotrone inside a radiation bunker at the headquarters of Belgian group IBA, which makes proton therapy machines for the treatment of cancer, in Louvain-la-Neuve, Belgium, July 22, 2016. Picture taken July 22, 2016. REUTERS/Francois Lenoir

Biologists work in a laboratory at Pluristem Theraputics in Haifa, Israel March 6, 2016. Israeli biotech firm Pluristem Therapeutics said they have developed a placenta-based cell therapy injection that can fully cure patients with multiple organ failure caused by high radiation exposure. Picture taken March 6, 2016. REUTERS/Baz Ratner 

Yaky Yanay, president and chief operating officer at Pluristem Therapeutics, smiles during an interview with Reuters in Haifa, Israel March 6, 2016. Israeli biotech firm Pluristem Therapeutics said they have developed a placenta-based cell therapy injection that can fully cure patients with multiple organ failure caused by high radiation exposure. Picture taken March 6, 2016. REUTERS/Baz Ratner 

Zami Aberman, chairman and chief executive officer at Pluristem Theraputics, smiles during an interview with Reuters in Haifa, Israel March 6, 2016. Israeli biotech firm Pluristem Therapeutics said they have developed a placenta-based cell therapy injection that can fully cure patients with multiple organ failure caused by high radiation exposure. Picture taken March 6, 2016. REUTERS/Baz Ratner 

Esther Lukasiewicz Hagai, Vice President of Medical and Clinical Affairs at Pluristem Therapeutics, holds a bottle of radiation therapy injection during an interview with Reuters in Haifa, Israel March 6, 2016. Israeli biotech firm Pluristem Therapeutics said they have developed a placenta-based cell therapy injection that can fully cure patients with multiple organ failure caused by high radiation exposure. Picture taken March 6, 2016. REUTERS/Baz Ratner 

Bottles containing radiation therapy injection are seen at Pluristem Theraputics in Haifa, Israel March 6, 2016. Israeli biotech firm Pluristem Therapeutics said they have developed a placenta-based cell therapy injection that can fully cure patients with multiple organ failure caused by high radiation exposure. Picture taken March 6, 2016. REUTERS/Baz Ratner 

A laboratory worker removes cells from a storage unit at Pluristem Theraputics in Haifa, Israel March 6, 2016. Israeli biotech firm Pluristem Therapeutics said they have developed a placenta-based cell therapy injection that can fully cure patients with multiple organ failure caused by high radiation exposure. Picture taken March 6, 2016. REUTERS/Baz Ratner 

Esther Lukasiewicz Hagai, Vice President of Medical and Clinical Affairs at Pluristem Therapeutics, holds a bottle of radiation therapy during an interview with Reuters in Haifa, Israel March 6, 2016. Israeli biotech firm Pluristem Therapeutics said they have developed a placenta-based cell therapy injection that can fully cure patients with multiple organ failure caused by high radiation exposure. Picture taken March 6, 2016. REUTERS/Baz Ratner 

Venezuela's President Hugo Chavez salutes upon arriving from Cuba at Simon Bolivar airport in Caracas March 16, 2012. Smiling and embracing supporters, Chavez flew home on Friday after surgery in Cuba for cancer that will require him to have radiation therapy ahead of October's re-election bid. REUTERS/Carlos Garcia Rawlins (VENEZUELA - Tags: POLITICS PROFILE HEALTH) 

Venezuela's President Hugo Chavez arrives from Cuba at Simon Bolivar airport in Caracas March 16, 2012. Smiling and embracing supporters, Chavez flew home on Friday after surgery in Cuba for cancer that will require him to have radiation therapy ahead of October's re-election bid. REUTERS/Carlos Garcia Rawlins (VENEZUELA - Tags: POLITICS HEALTH) 

Venezuela's President Hugo Chavez wipes his perspiration after arriving from Cuba at Simon Bolivar airport in Caracas March 16, 2012. Smiling and embracing supporters, Chavez flew home on Friday after surgery in Cuba for cancer that will require him to have radiation therapy ahead of October's re-election bid. REUTERS/Jorge Silva (VENEZUELA - Tags: POLITICS HEALTH) 

Venezuela's President Hugo Chavez arrives from Cuba at Simon Bolivar airport in Caracas March 16, 2012. Smiling and embracing supporters, Chavez flew home on Friday after surgery in Cuba for cancer that will require him to have radiation therapy ahead of October's re-election bid. REUTERS/Jorge Silva (VENEZUELA - Tags: POLITICS PROFILE HEALTH) 

Venezuela's President Hugo Chavez speaks after arriving from Cuba at Simon Bolivar airport in Caracas March 16, 2012. Smiling and embracing supporters, Chavez flew home on Friday after surgery in Cuba for cancer that will require him to have radiation therapy ahead of October's re-election bid. REUTERS/Jorge Silva (VENEZUELA - Tags: POLITICS PROFILE HEALTH) 

Venezuela's President Hugo Chavez speaks after arriving from Cuba at Simon Bolivar airport in Caracas March 16, 2012. Smiling and embracing supporters, Chavez flew home on Friday after surgery in Cuba for cancer that will require him to have radiation therapy ahead of October's re-election bid. REUTERS/Jorge Silva (VENEZUELA - Tags: POLITICS PROFILE HEALTH) 

Venezuela's President Hugo Chavez speaks after arriving from Cuba at Simon Bolivar airport in Caracas March 16, 2012. Smiling and embracing supporters, Chavez flew home on Friday after surgery in Cuba for cancer that will require him to have radiation therapy ahead of October's re-election bid. REUTERS/Jorge Silva (VENEZUELA - Tags: POLITICS PROFILE HEALTH) 

Nuclear physician Klaus Tatsch opeates with a radiation liquid on a cancer patient by the new radiation treatment for liver tumours called Selective Internal Radiation Therapy (SIRT) in Munich's university hospital, October 17, 2006. SIRT targets a very high radiation dose to tumours within the liver, regardless of their cell of origin, number, size or location. The spheres are implanted using a catheter placed in the artery feeding the liver and travel via the blood stream, where the spheres are targeted to the tumours within the liver. REUTERS/Alexandra Beier (GERMANY) 

Nuclear physician Klaus Tatsch looks at a radiation liquid during an operation on a cancer patient by the new radiation treatment for liver tumours called Selective Internal Radiation Therapy (SIRT) in Munich's university hospital, October 17, 2006. SIRT targets a very high radiation dose to tumours within the liver, regardless of their cell of origin, number, size or location. The spheres are implanted using a catheter placed in the artery feeding the liver and travel via the blood stream, where the spheres are targeted to the tumours within the liver. REUTERS/Alexandra Beier (GERMANY) 

Radiologist Maximilian Reiser (R) and nuclear physician Klaus Tatsch operate on a cancer patient by the new radiation treatment for liver tumours called Selective Internal Radiation Therapy (SIRT) in Munich's university hospital, October 17, 2006. SIRT targets a very high radiation dose to tumours within the liver, regardless of their cell of origin, number, size or location. The spheres are implanted using a catheter placed in the artery feeding the liver and travel via the blood stream, where the spheres are targeted to the tumours within the liver. REUTERS/Alexandra Beier (GERMANY) 

Radiologist Maximilian Reiser (R) and nuclear physician Klaus Tatsch operate on a cancer patient by the new radiation treatment for liver tumours called Selective Internal Radiation Therapy (SIRT) in Munich's university hospital, October 17, 2006. SIRT targets a very high radiation dose to tumours within the liver, regardless of their cell of origin, number, size or location. The spheres are implanted using a catheter placed in the artery feeding the liver and travel via the blood stream, where the spheres are targeted to the tumours within the liver. REUTERS/Alexandra Beier (GERMANY) 

Radiologists Christoph Timm (L) and Maximilian Reiser operate on a cancer patient with the new radiation treatment for liver tumours, called Selective Internal Radiation Therapy (SIRT) in Munich's university hospital, October 17, 2006. SIRT targets a very high radiation dose to tumours within the liver, regardless of their cell of origin, number, size or location. The spheres are implanted using a catheter placed in the artery feeding the liver and travel via the blood stream, where the spheres are targeted to the tumours within the liver. REUTERS/Alexandra Beier (GERMANY) 

Ukrainian girl Natalia, 10, victim of Chernobyl explosion, receives treatment for alopecia in Tarara, outside of Havana. Ukrainian girl Natalia, 10, a victim of radiation fallout from the 1986 power plant explosion in Chernobyl, receives treatment for alopecia at the Pediatric Hospital in Tarara, outside of Havana, April 26, 2005. Since 1990, Cuba has treated 18,000 Ukrainian children free of charge for loss of hair, skin disorders, cancer, leukemia and other illnesses attributed to the radioactivity unleashed by the reactor meltdown years before they were born. Picture taken April 26, 2005. REUTERS/Claudia Daut 

Ukrainian girl Anna, a victim of Chernobyl explosion, receives treatment for alopecia, the total loss of hair, in Tarara, outside Havana. Ukrainian girl Anna, 13, a victim of radiation fallout from the 1986 power plant explosion in Chernobyl, receives treatment for alopecia, the total loss of hair, at the Paediatric Hospital in Tarara, outside Havana, April 26, 2005. Since 1990, Cuba has treated 18,000 Ukrainian children free of charge for loss of hair, skin disorders, cancer, leukaemia and other illnesses attributed to the radioactivity unleashed by the reactor meltdown years before they were born. Picture taken April 26, 2005. REUTERS/Claudia Daut Pictures of the Month July 2005 

Roger Ebert, noted film critic for the Chicago Sun-Times, will start
radiation therapy in August 2003 as a follow-up to surgery he had in
February 2003 for cancer of the salivary gland. Ebert's doctors say his
prognosis is good and the treatments will not affect his work schedule.
Ebert is shown in this January 23, 2003 file photograph at the Sundance
Film Festival in Utah. REUTERS/Fred Prouser/Files

FSP/HB 

Nation of Islam leader Louis Farrakhan was recovering well in a Washington hospital on November 2, 2000 after surgery to treat rare complications related to radiation therapy he had several years ago for prostate cancer, his doctors said. Farrakhan speaks during a Baghdad news conference in this December 11, 1997 file picture.

JP